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Question 1
Incorrect
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A 42-year-old woman with a lengthy history of depression arrives at the Emergency Department after intentionally overdosing on the medication she takes for her heart condition. She informs you that she consumed verapamil SR 160 mg tablets approximately 30 minutes ago. However, her spouse discovered her immediately and promptly brought her to the hospital. Currently, she shows no symptoms. Typically, how much time passes before symptoms begin to manifest in cases of this overdose?
Your Answer: 3-6 hours
Correct Answer: 12-16 hours
Explanation:Calcium-channel blocker overdose is a serious condition that should always be taken seriously as it can be potentially life-threatening. The two most dangerous types of calcium channel blockers in overdose are verapamil and diltiazem. These medications work by binding to the alpha-1 subunit of L-type calcium channels, which prevents the entry of calcium into the cells. These channels play a crucial role in the functioning of cardiac myocytes, vascular smooth muscle cells, and islet beta-cells.
Significant toxicity can occur with the ingestion of more than 10 tablets of verapamil (160 mg or 240 mg immediate or sustained-release capsules) or diltiazem (180 mg, 240 mg or 360 mg immediate or sustained-release capsules). In children, even 1-2 tablets of immediate or sustained-release verapamil or diltiazem can be harmful. Symptoms usually appear within 1-2 hours of taking standard preparations, but with slow-release versions, the onset of severe toxicity may be delayed by 12-16 hours, with peak effects occurring after 24 hours.
The main clinical manifestations of calcium-channel blocker overdose include nausea and vomiting, low blood pressure, slow heart rate and first-degree heart block, heart muscle ischemia and stroke, kidney failure, pulmonary edema, and high blood sugar levels.
When managing a patient with calcium-channel blocker overdose, certain bedside investigations are crucial. These include checking blood glucose levels, performing an electrocardiogram (ECG), and obtaining an arterial blood gas sample. Additional investigations that can provide helpful information include assessing urea and electrolyte levels, conducting a chest X-ray to check for pulmonary edema, and performing an echocardiography.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 2
Incorrect
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A 35-year-old woman of Asian descent comes to the Emergency Department with swelling of the face, lips, and tongue. Despite receiving IM adrenaline, her symptoms do not improve. She mentions that her doctor recently prescribed her a new medication.
Which of the following drugs is most likely causing her symptoms?Your Answer: Bendroflumethiazide
Correct Answer: Ramipril
Explanation:Angiotensin-converting enzyme (ACE) inhibitors are the primary cause of drug-induced angioedema in the UK and USA, mainly due to their widespread use. The incidence of angioedema caused by ACE inhibitors ranges from 0.1 to 0.7% among recipients, with evidence suggesting a consistent and persistent risk each year. Interestingly, individuals of African descent are approximately five times more likely to experience this adverse reaction.
The most common symptoms observed in patients with ACE inhibitor-induced angioedema include swelling of the lips, tongue, or face. However, another manifestation of this condition is episodic abdominal pain caused by intestinal angioedema. Notably, urticaria (hives) and itching are absent in these cases.
The underlying mechanism of ACE inhibitor-induced angioedema appears to involve the activation of the complement system or other pro-inflammatory cytokines, such as prostaglandins and histamine. These substances trigger rapid dilation of blood vessels and the accumulation of fluid, leading to edema.
Although less frequently associated with angioedema, other medications that may cause this condition include angiotensin-receptor blockers (ARBs), nonsteroidal anti-inflammatory drugs (NSAIDs), bupropion (e.g., Zyban and Wellbutrin), beta-lactam antibiotics, statins, and proton pump inhibitors.
Fortunately, most cases of drug-induced angioedema are mild and can be effectively managed by discontinuing the medication and prescribing oral antihistamines.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 3
Incorrect
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A 45-year-old male patient comes in with loss of appetite, vomiting, fatigue, and disorientation. His blood tests show low sodium levels, and after further examination, he is diagnosed with drug-induced syndrome of inappropriate antidiuretic hormone secretion (SIADH).
Which of the following medications is most likely causing this presentation?Your Answer: Chloramphenicol
Correct Answer: Amitriptyline
Explanation:The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by the presence of low sodium levels and low osmolality due to the inappropriate and continuous release or action of the hormone, despite normal or increased blood volume. This leads to a decreased ability to excrete water.
There are several factors that can cause SIADH, with carbamazepine being a well-known example. These causes can be grouped into different categories. One category is CNS damage, which includes conditions like meningitis and subarachnoid hemorrhage. Another category is malignancy, with small-cell lung cancer being a common cause. Certain drugs, such as carbamazepine, SSRIs, amitriptyline, and morphine, can also trigger SIADH. Infections, such as pneumonia, lung abscess, and brain abscess, are another potential cause. Lastly, endocrine disorders like hypothyroidism can contribute to the development of SIADH. -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 4
Incorrect
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A 30-year-old woman is given a medication for a medical condition during her pregnancy. As a result, the newborn is born with a neural tube defect and hemorrhagic disease of the newborn.
Which of the listed medications is the most probable cause of these abnormalities?Your Answer: Heparin
Correct Answer: Carbamazepine
Explanation:There is an increased risk of neural tube defects in women with epilepsy who take carbamazepine during pregnancy, ranging from 2 to 10 times higher. Additionally, there is a risk of haemorrhagic disease of the newborn associated with this medication. It is crucial to have discussions about epilepsy treatments with women of childbearing age during the planning stages so that they can start early supplementation of folic acid.
Below is a list outlining the most commonly encountered drugs that have adverse effects during pregnancy:
ACE inhibitors (e.g. ramipril): If given in the second and third trimester, these medications can cause hypoperfusion, renal failure, and the oligohydramnios sequence.
Aminoglycosides (e.g. gentamicin): These drugs can lead to ototoxicity and deafness in the fetus.
Aspirin: High doses of aspirin can cause first-trimester abortions, delayed onset labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus. However, low doses (e.g. 75 mg) do not pose significant risks.
Benzodiazepines (e.g. diazepam): When given late in pregnancy, these medications can result in respiratory depression and a neonatal withdrawal syndrome.
Calcium-channel blockers: If given in the first trimester, these drugs can cause phalangeal abnormalities. If given in the second and third trimesters, they can lead to fetal growth retardation.
Carbamazepine: This medication is associated with haemorrhagic disease of the newborn and neural tube defects.
Chloramphenicol: Use of this drug can cause grey baby syndrome in newborns.
Corticosteroids: If given in the first trimester, corticosteroids may cause orofacial clefts in the fetus.
Danazol: When administered in the first trimester, danazol can cause masculinization of the female fetuses genitals.
Finasteride: Pregnant women should avoid handling finasteride tablets. Crushed or broken tablets can be absorbed through the skin and affect male sex organ development in the fetus.
Haloperidol: If given in the first trimester, haloperidol may cause limb malformations. In the third trimester, there is an increased risk of extrapyramidal symptoms in the neonate.
Heparin: Use of heparin during pregnancy is associated with an acceptable bleeding rate and a low rate of thrombotic recurrence in the mother.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 5
Incorrect
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You review a 65-year-old woman who has been diagnosed with atrial fibrillation and is currently taking warfarin. She has developed an infection that needs to be treated with an antibiotic.
Which antibiotic would be the most suitable and safe option for this patient?Your Answer: Metronidazole
Correct Answer: Cefalexin
Explanation:The use of antibiotics can impact the effectiveness of warfarin and other coumarin anticoagulants. This can lead to changes in the International Normalized Ratio (INR) and, in severe cases, increase the risk of bleeding. Some antibiotics, such as chloramphenicol, ciprofloxacin, co-trimoxazole, doxycycline, erythromycin, macrolides (e.g., clarithromycin), metronidazole, ofloxacin, and sulphonamide, are known to enhance the anticoagulant effect of warfarin. However, cefalexin is considered relatively safe and is the most suitable option in this situation.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 6
Correct
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A 25-year-old male is brought to the emergency department after intentionally ingesting 70 amitriptyline tablets. You administer activated charcoal to the patient. Which other medication, listed as an antidote on the RCEM/NPIS, can be used to treat tricyclic overdose?
Your Answer: Sodium bicarbonate
Explanation:In the latest guideline published in 2021 by RCEM and NPIS regarding antidote availability for emergency departments, it is emphasized that immediate access to sodium bicarbonate is essential for treating TCA overdose. It is worth noting that previous versions of the guideline included glucagon as a recommended treatment for TCA overdose, but this reference has been omitted in the latest edition.
Further Reading:
Salicylate poisoning, particularly from aspirin overdose, is a common cause of poisoning in the UK. One important concept to understand is that salicylate overdose leads to a combination of respiratory alkalosis and metabolic acidosis. Initially, the overdose stimulates the respiratory center, leading to hyperventilation and respiratory alkalosis. However, as the effects of salicylate on lactic acid production, breakdown into acidic metabolites, and acute renal injury occur, it can result in high anion gap metabolic acidosis.
The clinical features of salicylate poisoning include hyperventilation, tinnitus, lethargy, sweating, pyrexia (fever), nausea/vomiting, hyperglycemia and hypoglycemia, seizures, and coma.
When investigating salicylate poisoning, it is important to measure salicylate levels in the blood. The sample should be taken at least 2 hours after ingestion for symptomatic patients or 4 hours for asymptomatic patients. The measurement should be repeated every 2-3 hours until the levels start to decrease. Other investigations include arterial blood gas analysis, electrolyte levels (U&Es), complete blood count (FBC), coagulation studies (raised INR/PTR), urinary pH, and blood glucose levels.
To manage salicylate poisoning, an ABC approach should be followed to ensure a patent airway and adequate ventilation. Activated charcoal can be administered if the patient presents within 1 hour of ingestion. Oral or intravenous fluids should be given to optimize intravascular volume. Hypokalemia and hypoglycemia should be corrected. Urinary alkalinization with intravenous sodium bicarbonate can enhance the elimination of aspirin in the urine. In severe cases, hemodialysis may be necessary.
Urinary alkalinization involves targeting a urinary pH of 7.5-8.5 and checking it hourly. It is important to monitor for hypokalemia as alkalinization can cause potassium to shift from plasma into cells. Potassium levels should be checked every 1-2 hours.
In cases where the salicylate concentration is high (above 500 mg/L in adults or 350 mg/L in children), sodium bicarbonate can be administered intravenously. Hemodialysis is the treatment of choice for severe poisoning and may be indicated in cases of high salicylate levels, resistant metabolic acidosis, acute kidney injury, pulmonary edema, seizures and coma.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 7
Correct
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A 45-year-old woman is brought in by ambulance. She has ingested a significant amount of aspirin.
Which acid-base disorder would you anticipate to be present during the advanced stages of an aspirin overdose?Your Answer: Raised anion gap metabolic acidosis
Explanation:An overdose of aspirin often leads to a combination of respiratory alkalosis and metabolic acidosis. Initially, the stimulation of the respiratory center causes hyperventilation and results in respiratory alkalosis. However, as the overdose progresses, the direct acidic effects of aspirin cause an increase in the anion gap and metabolic acidosis.
Here is a summary of common causes for different acid-base disorders:
Respiratory alkalosis can be caused by hyperventilation due to factors such as anxiety, pulmonary embolism, CNS disorders (such as stroke or encephalitis), altitude, pregnancy, and the early stages of aspirin overdose.
Respiratory acidosis can occur in individuals with chronic obstructive pulmonary disease (COPD), life-threatening asthma, pulmonary edema, sedative drug overdose (such as opioids or benzodiazepines), neuromuscular diseases, and obesity.
Metabolic alkalosis can be caused by vomiting, potassium depletion (often due to diuretic usage), Cushing’s syndrome, and Conn’s syndrome.
Metabolic acidosis with a raised anion gap can result from conditions such as lactic acidosis (caused by factors like hypoxemia, shock, sepsis, or tissue infarction), ketoacidosis (associated with diabetes, starvation, or excessive alcohol consumption), renal failure, and poisoning (including the late stages of aspirin overdose, methanol or ethylene glycol ingestion).
Metabolic acidosis with a normal anion gap can be seen in renal tubular acidosis, diarrhea, ammonium chloride ingestion, and adrenal insufficiency.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 8
Incorrect
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A 28-year-old woman is brought in by ambulance after intentionally swallowing 17 tablets of 300 mg aspirin. The overdose occurred three hours ago.
What is true regarding her treatment in the Emergency Department?Your Answer: She should receive gastric lavage immediately
Correct Answer: No specific antidote is available in this case
Explanation:Salicylate poisoning is a fairly common form of poisoning that can lead to organ damage and death if not treated promptly. The symptoms of salicylate poisoning include nausea, vomiting, ringing in the ears, hearing loss, excessive sweating, dehydration, rapid breathing, flushed skin, and high fever in children. In severe cases, convulsions, swelling of the brain, coma, kidney failure, fluid in the lungs, and unstable heart function can occur.
The treatment for salicylate poisoning involves stabilizing the patient’s airway, breathing, and circulation as needed, preventing further absorption of the poison, enhancing its elimination from the body, correcting any metabolic abnormalities, and providing supportive care. Unfortunately, there is no specific antidote available for salicylates. If a large amount of salicylate has been ingested within the past hour (more than 4.5 grams in adults or more than 2 grams in children), gastric lavage (stomach pumping) and administration of activated charcoal (50 grams) are recommended to reduce absorption and increase elimination.
Medical investigations for salicylate poisoning should include measuring the level of salicylate in the blood, analyzing arterial blood gases, performing an electrocardiogram (ECG), checking blood glucose levels, assessing kidney function and electrolyte levels, and evaluating blood clotting. ECG abnormalities that may be present include widening of the QRS complex, AV block, and ventricular arrhythmias.
The severity of salicylate poisoning is determined by the level of salicylate in the blood. Mild poisoning is defined as a salicylate level below 450 mg/L, moderate poisoning is between 450-700 mg/L, and severe poisoning is above 700 mg/L. In severe cases, aggressive intravenous fluid therapy is necessary to correct dehydration, and administration of 1.26% sodium bicarbonate can help eliminate the salicylate from the body. It is important to maintain a urine pH of greater than 7.5, ideally between 8.0-8.5. However, forced alkaline diuresis is no longer recommended. Life-threatening cases may require admission to the intensive care unit, intubation and ventilation, and possibly hemodialysis.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 9
Correct
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A 45-year-old woman develops hypothyroidism secondary to the administration of a medication for a thyroid condition.
Which of the following medications is most likely to be responsible?Your Answer: Amiodarone
Explanation:Amiodarone has a chemical structure that is similar to thyroxine and has the ability to bind to the nuclear thyroid receptor. This medication has the potential to cause both hypothyroidism and hyperthyroidism, although hypothyroidism is more commonly observed, affecting around 5-10% of patients.
There are several side effects associated with the use of amiodarone. These include the formation of microdeposits in the cornea, increased sensitivity to sunlight resulting in photosensitivity, feelings of nausea, disturbances in sleep patterns, and the development of either hyperthyroidism or hypothyroidism. In addition, there have been reported cases of acute hepatitis and jaundice, peripheral neuropathy, lung fibrosis, and QT prolongation.
It is important to be aware of these potential side effects when considering the use of amiodarone as a treatment option. Regular monitoring and close medical supervision are necessary to detect and manage any adverse reactions that may occur.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 10
Incorrect
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A 35-year-old woman with a history of epilepsy presents with a complaint of gum swelling. Upon examination, significant gum hypertrophy is noted.
Which SPECIFIC anti-epileptic medication is she most likely to be prescribed?Your Answer: Sodium valproate
Correct Answer: Phenytoin
Explanation:Phenytoin is widely known for its ability to cause gum hypertrophy. This condition is believed to occur as a result of decreased folate levels, but studies have shown that taking folic acid supplements can help prevent it. In addition to gum hypertrophy, other side effects that may occur with phenytoin use include megaloblastic anemia, nystagmus, ataxia, hypertrichosis, pruritic rash, hirsutism, and drug-induced lupus.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 11
Incorrect
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A 35-year-old man is given a medication during the 2nd-trimester of his partner's pregnancy. As a result, the baby is born with a neural tube defect.
Which of the following medications is the most probable cause of these abnormalities?Your Answer: Gentamicin
Correct Answer: Trimethoprim
Explanation:The use of trimethoprim during the first trimester of pregnancy is linked to a higher risk of neural tube defects due to its interference with folate. If it is not possible to use an alternative antibiotic, it is recommended that pregnant women taking trimethoprim also take high-dose folic acid. However, the use of trimethoprim during the second and third trimesters of pregnancy is considered safe.
Here is a list outlining the commonly encountered drugs that have adverse effects during pregnancy:
ACE inhibitors (e.g. ramipril): If given in the second and third trimesters, they can cause hypoperfusion, renal failure, and the oligohydramnios sequence.
Aminoglycosides (e.g. gentamicin): They can cause ototoxicity and deafness.
Aspirin: High doses can lead to first-trimester abortions, delayed onset labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus. However, low doses (e.g. 75 mg) do not pose significant risks.
Benzodiazepines (e.g. diazepam): When given late in pregnancy, they can cause respiratory depression and a neonatal withdrawal syndrome.
Calcium-channel blockers: If given in the first trimester, they can cause phalangeal abnormalities. If given in the second and third trimesters, they can lead to fetal growth retardation.
Carbamazepine: It can cause haemorrhagic disease of the newborn and neural tube defects.
Chloramphenicol: It can cause grey baby syndrome.
Corticosteroids: If given in the first trimester, they may cause orofacial clefts.
Danazol: If given in the first trimester, it can cause masculinization of the female fetuses genitals.
Finasteride: Pregnant women should avoid handling finasteride as crushed or broken tablets can be absorbed through the skin and affect male sex organ development.
Haloperidol: If given in the first trimester, it may cause limb malformations. If given in the third trimester, there is an increased risk of extrapyramidal symptoms in the neonate.
Heparin: It can cause maternal bleeding and thrombocytopenia.
Isoniazid: It can lead to maternal liver damage and neuropathy and seizures in the neonate.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 12
Incorrect
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You are overseeing the care of a patient who has received intravenous lipid emulsion. As the patient recovers over the next hour, it is important to continue monitoring for which side effect of this medication?
Your Answer: Optic neuritis
Correct Answer: Pancreatitis
Explanation:Lipid emulsion is known to cause pancreatitis as a common side effect. According to the AAGBI guidelines, patients who are given lipid emulsion should be closely monitored with regular clinical evaluations. This includes conducting amylase or lipase tests daily for two days after receiving the emulsion.
Further Reading:
Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.
However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.
The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.
If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.
It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 13
Incorrect
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A 40-year-old woman is prescribed haloperidol for a psychiatric condition in the 2nd-trimester of her pregnancy. As a result of this treatment, the newborn develops a malformation.
Which of the following malformations is the most likely to occur as a result of using this medication during pregnancy?Your Answer: Premature closure of the ductus arteriosus
Correct Answer: Extrapyramidal syndrome
Explanation:Haloperidol, when administered during the third trimester of pregnancy, can lead to extrapyramidal symptoms in the newborn. These symptoms may include agitation, poor feeding, excessive sleepiness, and difficulty breathing. The severity of these side effects can vary, with some infants requiring intensive care and extended hospital stays. It is important to closely monitor exposed neonates for signs of extrapyramidal syndrome or withdrawal. Haloperidol should only be used during pregnancy if the benefits clearly outweigh the risks to the fetus.
Below is a list outlining commonly encountered drugs that have adverse effects during pregnancy:
ACE inhibitors (e.g. ramipril): If given during the second and third trimesters, these drugs can cause hypoperfusion, renal failure, and the oligohydramnios sequence.
Aminoglycosides (e.g. gentamicin): These drugs can cause ototoxicity and deafness in the fetus.
Aspirin: High doses of aspirin can lead to first-trimester abortions, delayed onset of labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus. However, low doses (e.g. 75 mg) do not pose significant risks.
Benzodiazepines (e.g. diazepam): When administered late in pregnancy, these drugs can cause respiratory depression and a neonatal withdrawal syndrome.
Calcium-channel blockers: If given during the first trimester, these drugs can cause phalangeal abnormalities. If given during the second and third trimesters, they can result in fetal growth retardation.
Carbamazepine: This drug can lead to hemorrhagic disease of the newborn and neural tube defects.
Chloramphenicol: Administration of chloramphenicol can cause gray baby syndrome in newborns.
Corticosteroids: If given during the first trimester, corticosteroids may cause orofacial clefts in the fetus.
Danazol: When administered during the first trimester, danazol can cause masculinization of the female fetuses genitals.
Finasteride: Pregnant women should avoid handling finasteride as crushed or broken tablets can be absorbed through the skin and affect male sex organ development.
Haloperidol: If given during the first trimester, haloperidol may cause limb malformations. If given during the third trimester, there is an increased risk of extrapyramidal symptoms in the neonate.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 14
Incorrect
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A 32 year old male is brought into the emergency department by coworkers. The patient was having lunch when he started to experience wheezing and noticed swelling in his lips. He is immediately taken to the resuscitation bay. One of the coworkers mentions that they saw the patient take a pill with his meal. Which of the following medications or medication classes is the primary culprit for inducing anaphylaxis?
Your Answer: Angiotensin converting enzyme Inhibitors
Correct Answer: Antibiotics
Explanation:In cases of anaphylaxis, it is important to administer non-sedating antihistamines after adrenaline administration and initial resuscitation. Previous guidelines recommended the use of chlorpheniramine and hydrocortisone as third line treatments, but the 2021 guidelines have removed this recommendation. Corticosteroids are no longer advised. Instead, it is now recommended to use non-sedating antihistamines such as cetirizine, loratadine, and fexofenadine, as alternatives to the sedating antihistamine chlorpheniramine. The top priority treatments for anaphylaxis are adrenaline, oxygen, and fluids. The Resuscitation Council advises that administration of non-sedating antihistamines should occur after the initial resuscitation.
Further Reading:
Anaphylaxis is a severe and life-threatening hypersensitivity reaction that can have sudden onset and progression. It is characterized by skin or mucosal changes and can lead to life-threatening airway, breathing, or circulatory problems. Anaphylaxis can be allergic or non-allergic in nature.
In allergic anaphylaxis, there is an immediate hypersensitivity reaction where an antigen stimulates the production of IgE antibodies. These antibodies bind to mast cells and basophils. Upon re-exposure to the antigen, the IgE-covered cells release histamine and other inflammatory mediators, causing smooth muscle contraction and vasodilation.
Non-allergic anaphylaxis occurs when mast cells degrade due to a non-immune mediator. The clinical outcome is the same as in allergic anaphylaxis.
The management of anaphylaxis is the same regardless of the cause. Adrenaline is the most important drug and should be administered as soon as possible. The recommended doses for adrenaline vary based on age. Other treatments include high flow oxygen and an IV fluid challenge. Corticosteroids and chlorpheniramine are no longer recommended, while non-sedating antihistamines may be considered as third-line treatment after initial stabilization of airway, breathing, and circulation.
Common causes of anaphylaxis include food (such as nuts, which is the most common cause in children), drugs, and venom (such as wasp stings). Sometimes it can be challenging to determine if a patient had a true episode of anaphylaxis. In such cases, serum tryptase levels may be measured, as they remain elevated for up to 12 hours following an acute episode of anaphylaxis.
The Resuscitation Council (UK) provides guidelines for the management of anaphylaxis, including a visual algorithm that outlines the recommended steps for treatment.
https://www.resus.org.uk/sites/default/files/2021-05/Emergency%20Treatment%20of%20Anaphylaxis%20May%202021_0.pdf -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 15
Correct
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A 32-year-old woman with a known history of asthma presents with a headache, nausea, and abdominal pain. Her heart rate is elevated at 117 bpm. She currently takes a salbutamol inhaler and theophylline for her asthma. She had visited the Emergency Department a few days earlier and was prescribed an antibiotic.
Which antibiotic was most likely prescribed to this patient?Your Answer: Ciprofloxacin
Explanation:Theophylline is a medication used to treat severe asthma. It is a bronchodilator that comes in modified-release forms, which can maintain therapeutic levels in the blood for 12 hours. Theophylline works by inhibiting phosphodiesterase and blocking the breakdown of cyclic AMP. It also competes with adenosine on A1 and A2 receptors.
Achieving the right dose of theophylline can be challenging because there is a narrow range between therapeutic and toxic levels. The half-life of theophylline can be influenced by various factors, further complicating dosage adjustments. It is recommended to aim for serum levels of 10-20 mg/l six to eight hours after the last dose.
Unlike many other medications, the specific brand of theophylline can significantly impact its effects. Therefore, it is important to prescribe theophylline by both its brand name and generic name.
Several factors can increase the half-life of theophylline, including heart failure, cirrhosis, viral infections, and certain drugs. Conversely, smoking, heavy drinking, and certain medications can decrease the half-life of theophylline.
There are several drugs that can either increase or decrease the plasma concentration of theophylline. Calcium channel blockers, cimetidine, fluconazole, macrolides, methotrexate, and quinolones can increase the concentration. On the other hand, carbamazepine, phenobarbitol, phenytoin, rifampicin, and St. John’s wort can decrease the concentration.
The clinical symptoms of theophylline toxicity are more closely associated with acute overdose rather than chronic overexposure. Common symptoms include headache, dizziness, nausea, vomiting, abdominal pain, rapid heartbeat, dysrhythmias, seizures, mild metabolic acidosis, low potassium, low magnesium, low phosphates, abnormal calcium levels, and high blood sugar.
Seizures are more prevalent in acute overdose cases, while chronic overdose typically presents with minimal gastrointestinal symptoms. Cardiac dysrhythmias are more common in chronic overdose situations compared to acute overdose.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 16
Incorrect
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A 35-year-old woman is given diclofenac for arthritis during her second trimester of pregnancy. As a result of this medication, the baby develops a birth defect.
What is the most probable birth defect that can occur due to the use of diclofenac during pregnancy?Your Answer: Haemorrhagic disease of the newborn
Correct Answer: Premature closure of the ductus arteriosus
Explanation:The use of NSAIDs during the third trimester of pregnancy is associated with several risks. These risks include delayed onset of labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus, which is a condition characterized by bilirubin-induced brain dysfunction. Additionally, there is a slight increase in the risk of first-trimester abortion if NSAIDs are used early in pregnancy.
Below is a list outlining the most commonly encountered drugs that have adverse effects during pregnancy:
Drug: ACE inhibitors (e.g. ramipril)
Adverse effects: If given in the second and third trimester, ACE inhibitors can cause hypoperfusion, renal failure, and the oligohydramnios sequence.Drug: Aminoglycosides (e.g. gentamicin)
Adverse effects: Aminoglycosides can cause ototoxicity, leading to deafness in the fetus.Drug: Aspirin
Adverse effects: High doses of aspirin can cause first-trimester abortions, delayed onset of labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus. However, low doses (e.g. 75 mg) have no significant associated risk.Drug: Benzodiazepines (e.g. diazepam)
Adverse effects: When given late in pregnancy, benzodiazepines can cause respiratory depression and a neonatal withdrawal syndrome.Drug: Calcium-channel blockers
Adverse effects: If given in the first trimester, calcium-channel blockers can cause phalangeal abnormalities. If given in the second and third trimester, they can cause fetal growth retardation. -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 17
Incorrect
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You are following up on a 21-year-old patient you saw who was admitted following a paracetamol overdose. Which of the following is a poor prognostic indicator and indication for liver transplant in paracetamol overdose?
Your Answer: Arterial pH < 7.30 on or after day 2 following overdose
Correct Answer:
Explanation:A pH level in the arteries that is below 7.30 on or after the second day following a paracetamol overdose is considered a poor indicator of prognosis. Additionally, a prolonged prothrombin time (PT) of over 100 seconds (indicated by an international normalized ratio (INR) of over 6.5), along with a high plasma creatinine level of over 300 μmol/L and grade 3 or 4 hepatic encephalopathy, are also poor prognostic indicators and may indicate the need for a liver transplant. Furthermore, an increase in PT between the third and fourth day after the overdose is also considered a poor prognostic indicator.
Further Reading:
Paracetamol poisoning occurs when the liver is unable to metabolize paracetamol properly, leading to the production of a toxic metabolite called N-acetyl-p-benzoquinone imine (NAPQI). Normally, NAPQI is conjugated by glutathione into a non-toxic form. However, during an overdose, the liver’s conjugation systems become overwhelmed, resulting in increased production of NAPQI and depletion of glutathione stores. This leads to the formation of covalent bonds between NAPQI and cell proteins, causing cell death in the liver and kidneys.
Symptoms of paracetamol poisoning may not appear for the first 24 hours or may include abdominal symptoms such as nausea and vomiting. After 24 hours, hepatic necrosis may develop, leading to elevated liver enzymes, right upper quadrant pain, and jaundice. Other complications can include encephalopathy, oliguria, hypoglycemia, renal failure, and lactic acidosis.
The management of paracetamol overdose depends on the timing and amount of ingestion. Activated charcoal may be given if the patient presents within 1 hour of ingesting a significant amount of paracetamol. N-acetylcysteine (NAC) is used to increase hepatic glutathione production and is given to patients who meet specific criteria. Blood tests are taken to assess paracetamol levels, liver function, and other parameters. Referral to a medical or liver unit may be necessary, and psychiatric follow-up should be considered for deliberate overdoses.
In cases of staggered ingestion, all patients should be treated with NAC without delay. Blood tests are also taken, and if certain criteria are met, NAC can be discontinued. Adverse reactions to NAC are common and may include anaphylactoid reactions, rash, hypotension, and nausea. Treatment for adverse reactions involves medications such as chlorpheniramine and salbutamol, and the infusion may be stopped if necessary.
The prognosis for paracetamol poisoning can be poor, especially in cases of severe liver injury. Fulminant liver failure may occur, and liver transplant may be necessary. Poor prognostic indicators include low arterial pH, prolonged prothrombin time, high plasma creatinine, and hepatic encephalopathy.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 18
Incorrect
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A 65-year-old patient with a past medical history of chronic congestive cardiac failure complains of feeling fatigued and generally not well. She is currently on high doses of furosemide as prescribed by her heart failure specialist. Upon reviewing her blood test results, you observe that her electrolyte levels are abnormal.
Which of the following electrolyte imbalances is most likely to be present?Your Answer: Low sodium, normal potassium
Correct Answer: Low sodium, low potassium
Explanation:Loop diuretics, like furosemide, commonly result in several electrolyte imbalances. These imbalances include hyponatremia, which is a decrease in sodium levels in the blood. Another common imbalance is hypokalemia, which refers to low levels of potassium. Additionally, loop diuretics can cause hypocalcemia, a condition characterized by low levels of calcium in the blood. Another electrolyte affected by loop diuretics is magnesium, as they can lead to hypomagnesemia, which is a deficiency of magnesium. Lastly, loop diuretics can cause hypochloremic alkalosis, which is a condition characterized by low levels of chloride in the blood and an increase in blood pH.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 19
Incorrect
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A 21 year old male is brought to the emergency department by his parents and admits to ingesting 48 paracetamol tablets. What are the criteria for administering activated charcoal in this case?
Your Answer: Patient presents within 1 hour of ingesting paracetamol and stated dose is in excess of 75 mg/kg
Correct Answer: Patient presents within 1 hour of ingesting paracetamol and stated dose is in excess of 150 mg/kg
Explanation:Activated charcoal should be given to patients who have ingested paracetamol and meet two criteria: they must present within one hour of ingestion, and they must have taken a dose of paracetamol that is equal to or greater than 150 mg/kg. The recommended dose of activated charcoal is 50g, which is typically administered as 300ml. It is important to note that the dose criteria of 150 mg/kg is based on the amount of paracetamol reported by the patient, not on paracetamol levels, which should not be assessed until at least four hours after ingestion.
Further Reading:
Paracetamol poisoning occurs when the liver is unable to metabolize paracetamol properly, leading to the production of a toxic metabolite called N-acetyl-p-benzoquinone imine (NAPQI). Normally, NAPQI is conjugated by glutathione into a non-toxic form. However, during an overdose, the liver’s conjugation systems become overwhelmed, resulting in increased production of NAPQI and depletion of glutathione stores. This leads to the formation of covalent bonds between NAPQI and cell proteins, causing cell death in the liver and kidneys.
Symptoms of paracetamol poisoning may not appear for the first 24 hours or may include abdominal symptoms such as nausea and vomiting. After 24 hours, hepatic necrosis may develop, leading to elevated liver enzymes, right upper quadrant pain, and jaundice. Other complications can include encephalopathy, oliguria, hypoglycemia, renal failure, and lactic acidosis.
The management of paracetamol overdose depends on the timing and amount of ingestion. Activated charcoal may be given if the patient presents within 1 hour of ingesting a significant amount of paracetamol. N-acetylcysteine (NAC) is used to increase hepatic glutathione production and is given to patients who meet specific criteria. Blood tests are taken to assess paracetamol levels, liver function, and other parameters. Referral to a medical or liver unit may be necessary, and psychiatric follow-up should be considered for deliberate overdoses.
In cases of staggered ingestion, all patients should be treated with NAC without delay. Blood tests are also taken, and if certain criteria are met, NAC can be discontinued. Adverse reactions to NAC are common and may include anaphylactoid reactions, rash, hypotension, and nausea. Treatment for adverse reactions involves medications such as chlorpheniramine and salbutamol, and the infusion may be stopped if necessary.
The prognosis for paracetamol poisoning can be poor, especially in cases of severe liver injury. Fulminant liver failure may occur, and liver transplant may be necessary. Poor prognostic indicators include low arterial pH, prolonged prothrombin time, high plasma creatinine, and hepatic encephalopathy.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 20
Correct
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A 35-year-old man with a history of bipolar affective disorder presents with symptoms suggestive of lithium toxicity.
Which of the following symptoms is LEAST likely to be observed?Your Answer: SIADH
Explanation:SIADH is a medical condition that is not brought on by lithium toxicity. However, lithium toxicity does have its own distinct set of symptoms. These symptoms include nausea and vomiting, diarrhea, tremors, ataxia, confusion, increased muscle tone, clonus, nephrogenic diabetes insipidus, convulsions, coma, and renal failure. It is important to note that SIADH and lithium toxicity are separate conditions with their own unique characteristics.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 21
Incorrect
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A 30-year-old man has ingested an excessive amount of paracetamol. He consumed the overdose 12 hours ago and is unsure of the number of tablets he has taken.
Which of the following substances can be utilized as an antidote for paracetamol overdose?Your Answer: Octreotide
Correct Answer: Methionine
Explanation:The primary treatment for paracetamol overdose is acetylcysteine. Acetylcysteine is an extremely effective antidote, but its effectiveness decreases quickly if administered more than a few hours after a significant ingestion. Ingestions that exceed 75 mg/kg are considered to be significant.
For patients who decline treatment, methionine is a helpful alternative. It is taken orally in a dosage of 2.5 g every 4 hours, with a total dose of 10 g.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 22
Correct
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A 35-year-old woman with a history of heavy menstrual bleeding has ingested an excessive amount of ferrous sulfate.
What are the possible antidotes that can be administered in cases of iron salt poisoning?Your Answer: Desferrioxamine
Explanation:There are various specific remedies available for different types of poisons and overdoses. The following list provides an outline of some of these antidotes:
Poison: Benzodiazepines
Antidote: FlumazenilPoison: Beta-blockers
Antidotes: Atropine, Glucagon, InsulinPoison: Carbon monoxide
Antidote: OxygenPoison: Cyanide
Antidotes: Hydroxocobalamin, Sodium nitrite, Sodium thiosulphatePoison: Ethylene glycol
Antidotes: Ethanol, FomepizolePoison: Heparin
Antidote: Protamine sulphatePoison: Iron salts
Antidote: DesferrioxaminePoison: Isoniazid
Antidote: PyridoxinePoison: Methanol
Antidotes: Ethanol, FomepizolePoison: Opioids
Antidote: NaloxonePoison: Organophosphates
Antidotes: Atropine, PralidoximePoison: Paracetamol
Antidotes: Acetylcysteine, MethioninePoison: Sulphonylureas
Antidotes: Glucose, OctreotidePoison: Thallium
Antidote: Prussian bluePoison: Warfarin
Antidote: Vitamin K, Fresh frozen plasma (FFP)By utilizing these specific antidotes, medical professionals can effectively counteract the harmful effects of various poisons and overdoses.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 23
Correct
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A 25-year-old woman with a previous diagnosis of depression is admitted to the emergency department following an unintentional ingestion of amitriptyline tablets. Which toxidrome is commonly associated with an overdose of amitriptyline?
Your Answer: Anticholinergic
Explanation:An overdose of Amitriptyline, a tricyclic antidepressant, leads to a toxic effect known as anticholinergic toxidrome. This occurs when the muscarinic acetylcholine receptors are blocked, causing the characteristic signs and symptoms associated with this condition.
Further Reading:
Tricyclic antidepressant (TCA) overdose is a common occurrence in emergency departments, with drugs like amitriptyline and dosulepin being particularly dangerous. TCAs work by inhibiting the reuptake of norepinephrine and serotonin in the central nervous system. In cases of toxicity, TCAs block various receptors, including alpha-adrenergic, histaminic, muscarinic, and serotonin receptors. This can lead to symptoms such as hypotension, altered mental state, signs of anticholinergic toxicity, and serotonin receptor effects.
TCAs primarily cause cardiac toxicity by blocking sodium and potassium channels. This can result in a slowing of the action potential, prolongation of the QRS complex, and bradycardia. However, the blockade of muscarinic receptors also leads to tachycardia in TCA overdose. QT prolongation and Torsades de Pointes can occur due to potassium channel blockade. TCAs can also have a toxic effect on the myocardium, causing decreased cardiac contractility and hypotension.
Early symptoms of TCA overdose are related to their anticholinergic properties and may include dry mouth, pyrexia, dilated pupils, agitation, sinus tachycardia, blurred vision, flushed skin, tremor, and confusion. Severe poisoning can lead to arrhythmias, seizures, metabolic acidosis, and coma. ECG changes commonly seen in TCA overdose include sinus tachycardia, widening of the QRS complex, prolongation of the QT interval, and an R/S ratio >0.7 in lead aVR.
Management of TCA overdose involves ensuring a patent airway, administering activated charcoal if ingestion occurred within 1 hour and the airway is intact, and considering gastric lavage for life-threatening cases within 1 hour of ingestion. Serial ECGs and blood gas analysis are important for monitoring. Intravenous fluids and correction of hypoxia are the first-line therapies. IV sodium bicarbonate is used to treat haemodynamic instability caused by TCA overdose, and benzodiazepines are the treatment of choice for seizure control. Other treatments that may be considered include glucagon, magnesium sulfate, and intravenous lipid emulsion.
There are certain things to avoid in TCA overdose, such as anti-arrhythmics like quinidine and flecainide, as they can prolonged depolarization.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 24
Incorrect
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A 70-year-old man with atrial fibrillation comes to the Emergency Department with an unrelated medical issue. While reviewing his medications, you find out that he is taking warfarin as part of his treatment.
Which ONE of the following beverages should he avoid?Your Answer: Milk
Correct Answer: Cranberry juice
Explanation:Warfarin has been found to heighten the likelihood of bleeding events when consumed alongside specific juices, such as cranberry juice and grapefruit juice. As a result, individuals who are taking warfarin should be cautioned against consuming these beverages. For more information on this topic, please refer to the BNF section on warfarin interactions and the interaction between warfarin and cranberry juice.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 25
Correct
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A 60-year-old woman comes in with a red, hot, swollen great toe. The diagnosis is acute gout. You decide to start her on a non-steroidal anti-inflammatory drug (NSAID). Her husband was recently diagnosed with a peptic ulcer after an endoscopy, and she is worried about the potential side effects of NSAIDs.
Which of the following NSAIDs has the lowest occurrence of side effects?Your Answer: Ibuprofen
Explanation:The differences in anti-inflammatory activity among NSAIDs are minimal, but there is significant variation in how individuals respond to and tolerate these drugs. Approximately 60% of patients will experience a positive response to any NSAID, and those who do not respond to one may find relief with another. Pain relief typically begins shortly after taking the first dose, and a full analgesic effect is usually achieved within a week. However, it may take up to 3 weeks to see an anti-inflammatory effect, which may not be easily assessed. If desired results are not achieved within these timeframes, it is recommended to try a different NSAID.
NSAIDs work by reducing the production of prostaglandins through the inhibition of the enzyme cyclo-oxygenase. Different NSAIDs vary in their selectivity for inhibiting different types of cyclo-oxygenase. Selective inhibition of cyclo-oxygenase-2 is associated with a lower risk of gastrointestinal intolerance. Other factors also play a role in susceptibility to gastrointestinal effects, so the choice of NSAID should consider the incidence of gastrointestinal and other side effects.
Ibuprofen, a propionic acid derivative, possesses anti-inflammatory, analgesic, and antipyretic properties. It generally has fewer side effects compared to other non-selective NSAIDs, but its anti-inflammatory properties are weaker. For rheumatoid arthritis, doses of 1.6 to 2.4 g daily are required, and it may not be suitable for conditions where inflammation is prominent, such as acute gout.
Naproxen is often a preferred choice due to its combination of good efficacy and low incidence of side effects. However, it does have a higher occurrence of side effects compared to ibuprofen.
Ketoprofen and diclofenac have similar anti-inflammatory properties to ibuprofen but are associated with more side effects.
Indometacin has an action that is equal to or superior to naproxen, but it also has a high incidence of side effects, including headache, dizziness, and gastrointestinal disturbances.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 26
Incorrect
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A 70-year-old patient comes in after a chronic overdose of digoxin. She has experienced multiple episodes of vomiting, feels extremely tired, and reports that her vision seems to have a yellow tint.
What is the indication for administering DigiFab in this patient?Your Answer: Heart rate of 40 bpm
Correct Answer: Coexistent renal failure
Explanation:Digoxin-specific antibody (DigiFab) is an antidote used to counteract digoxin overdose. It is a purified and sterile preparation of digoxin-immune ovine Fab immunoglobulin fragments. These fragments are derived from healthy sheep that have been immunized with a digoxin derivative called digoxin-dicarboxymethoxylamine (DDMA). DDMA is a digoxin analogue that contains the essential cyclopentanoperhydrophenanthrene: lactone ring moiety coupled to keyhole limpet hemocyanin (KLH).
DigiFab has a higher affinity for digoxin compared to the affinity of digoxin for its sodium pump receptor, which is believed to be the receptor responsible for its therapeutic and toxic effects. When administered to a patient who has overdosed on digoxin, DigiFab binds to digoxin molecules, reducing the levels of free digoxin in the body. This shift in equilibrium away from binding to the receptors helps to reduce the cardiotoxic effects of digoxin. The Fab-digoxin complexes are then eliminated from the body through the kidney and reticuloendothelial system.
The indications for using DigiFab in cases of acute and chronic digoxin toxicity are summarized below:
Acute digoxin toxicity:
– Cardiac arrest
– Life-threatening arrhythmia
– Potassium level >5 mmol/l
– Ingestion of >10 mg of digoxin (in adults)
– Ingestion of >4 mg of digoxin (in children)
– Digoxin level >12 ng/mlChronic digoxin toxicity:
– Cardiac arrest
– Life-threatening arrhythmia
– Significant gastrointestinal symptoms
– Symptoms of digoxin toxicity in the presence of renal failure -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 27
Correct
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A 32-year-old woman comes to the clinic complaining of palpitations. During an ECG, it is found that she has newly developed QT prolongation. She mentions that her doctor recently prescribed her a new medication and wonders if that could be the reason.
Which of the following medications is most likely to cause QT interval prolongation?Your Answer: Citalopram
Explanation:Prolongation of the QT interval can lead to a dangerous ventricular arrhythmia called torsades de pointes, which can result in sudden cardiac death. There are several commonly used medications that are known to cause QT prolongation.
Low levels of potassium (hypokalaemia) and magnesium (hypomagnesaemia) can increase the risk of QT prolongation. For example, diuretics can interact with QT-prolonging drugs by causing hypokalaemia.
The QT interval varies with heart rate, and formulas are used to correct the QT interval for heart rate. Once corrected, it is referred to as the QTc interval. The QTc interval is typically reported on the ECG printout. A normal QTc interval is less than 440 ms.
If the QTc interval is greater than 440 ms but less than 500 ms, it is considered borderline. Although there may be some variation in the literature, a QTc interval within these values is generally considered borderline prolonged. In such cases, it is important to consider reducing the dose of QT-prolonging drugs or switching to an alternative medication that does not prolong the QT interval.
A prolonged QTc interval exceeding 500 ms is clinically significant and is likely to increase the risk of arrhythmia. Any medications that prolong the QT interval should be reviewed immediately.
Here are some commonly encountered drugs that are known to prolong the QT interval:
Antimicrobials:
– Erythromycin
– Clarithromycin
– Moxifloxacin
– Fluconazole
– KetoconazoleAntiarrhythmics:
– Dronedarone
– Sotalol
– Quinidine
– Amiodarone
– FlecainideAntipsychotics:
– Risperidone
– Fluphenazine
– Haloperidol
– Pimozide
– Chlorpromazine
– Quetiapine
– ClozapineAntidepressants:
– Citalopram/escitalopram
– Amitriptyline
– Clomipramine
– Dosulepin
– Doxepin
– Imipramine
– LofepramineAntiemetics:
– Domperidone
– Droperidol
– Ondansetron/GranisetronOthers:
– Methadone
– Protein kinase inhibitors (e.g. sunitinib) -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 28
Incorrect
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A 15 year old male is brought to the emergency department by his parents and admits to taking 32 paracetamol tablets 6 hours ago. Blood tests are conducted, including paracetamol levels. What is the paracetamol level threshold above which the ingestion is deemed 'significant'?
Your Answer: 10 mg/kg/24 hours
Correct Answer: 75 mg/kg/24 hours
Explanation:If someone consumes at least 75 mg of paracetamol per kilogram of body weight within a 24-hour period, it is considered to be a significant ingestion. Ingesting more than 150 mg of paracetamol per kilogram of body weight within 24 hours poses a serious risk of harm.
Further Reading:
Paracetamol poisoning occurs when the liver is unable to metabolize paracetamol properly, leading to the production of a toxic metabolite called N-acetyl-p-benzoquinone imine (NAPQI). Normally, NAPQI is conjugated by glutathione into a non-toxic form. However, during an overdose, the liver’s conjugation systems become overwhelmed, resulting in increased production of NAPQI and depletion of glutathione stores. This leads to the formation of covalent bonds between NAPQI and cell proteins, causing cell death in the liver and kidneys.
Symptoms of paracetamol poisoning may not appear for the first 24 hours or may include abdominal symptoms such as nausea and vomiting. After 24 hours, hepatic necrosis may develop, leading to elevated liver enzymes, right upper quadrant pain, and jaundice. Other complications can include encephalopathy, oliguria, hypoglycemia, renal failure, and lactic acidosis.
The management of paracetamol overdose depends on the timing and amount of ingestion. Activated charcoal may be given if the patient presents within 1 hour of ingesting a significant amount of paracetamol. N-acetylcysteine (NAC) is used to increase hepatic glutathione production and is given to patients who meet specific criteria. Blood tests are taken to assess paracetamol levels, liver function, and other parameters. Referral to a medical or liver unit may be necessary, and psychiatric follow-up should be considered for deliberate overdoses.
In cases of staggered ingestion, all patients should be treated with NAC without delay. Blood tests are also taken, and if certain criteria are met, NAC can be discontinued. Adverse reactions to NAC are common and may include anaphylactoid reactions, rash, hypotension, and nausea. Treatment for adverse reactions involves medications such as chlorpheniramine and salbutamol, and the infusion may be stopped if necessary.
The prognosis for paracetamol poisoning can be poor, especially in cases of severe liver injury. Fulminant liver failure may occur, and liver transplant may be necessary. Poor prognostic indicators include low arterial pH, prolonged prothrombin time, high plasma creatinine, and hepatic encephalopathy.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 29
Incorrect
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A 35-year-old woman has recently started taking a new medication. She is experiencing severe muscle pains.
Which ONE of the following drugs is most likely to cause myopathy as a side effect?Your Answer: Digoxin
Correct Answer: Simvastatin
Explanation:Statins, although generally safe and well-tolerated, can cause myopathy and myotoxicity. This range of muscle-related side effects can vary from mild muscle pain to the most severe case of rhabdomyolysis, which can lead to kidney failure, blood clotting issues, and even death.
The different levels of myotoxicity associated with statins are as follows:
– Myalgia: muscle symptoms without an increase in creatine kinase (CK) levels.
– Asymptomatic myopathy: elevated CK levels without muscle symptoms.
– Myositis: muscle symptoms with CK levels elevated less than 10 times the upper limit of normal.
– Rhabdomyolysis: muscle symptoms with CK levels elevated more than 10 times the upper limit of normal, potentially leading to myoglobinuria (presence of myoglobin in urine) and renal failure.Most statins are broken down by the cytochrome P450 enzyme system. When taken with drugs that strongly inhibit this system, the concentration of statins in the blood can significantly increase. This, in turn, raises the risk of myopathy. A well-known example of this is the combination of statins with macrolide antibiotics like erythromycin and clarithromycin. Co-prescribing these drugs with statins has been linked to a higher risk of myopathy, hospitalization due to rhabdomyolysis, acute kidney injury, and increased mortality rates.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 30
Incorrect
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A 42-year-old woman with a long history of anxiety presents having taken a deliberate overdose of the pills she takes for insomnia. She informs you that the pill she takes for this condition is zolpidem 10 mg. She consumed the pills approximately 2 hours ago. She is currently experiencing tachycardia, with her most recent heart rate reading being 120 beats per minute. She weighs 65 kg. You administer a dose of propranolol, but there is no improvement in her condition.
Which of the following treatments could now be given to support her cardiovascular system?Your Answer: Potassium infusion
Correct Answer: High dose insulin – euglycaemic therapy
Explanation:Calcium-channel blocker overdose is a serious condition that can be life-threatening. The most dangerous types of calcium channel blockers in overdose are verapamil and diltiazem. These medications work by binding to the alpha-1 subunit of L-type calcium channels, which prevents the entry of calcium into cells. These channels are important for the functioning of cardiac myocytes, vascular smooth muscle cells, and islet beta-cells.
When managing a patient with calcium-channel blocker overdose, it is crucial to follow the standard ABC approach for resuscitation. If there is a risk of life-threatening toxicity, early intubation and ventilation should be considered. Invasive blood pressure monitoring is also necessary if hypotension and shock are developing.
The specific treatments for calcium-channel blocker overdose primarily focus on supporting the cardiovascular system. These treatments include:
1. Fluid resuscitation: Administer up to 20 mL/kg of crystalloid solution.
2. Calcium administration: This can temporarily increase blood pressure and heart rate. Options include 10% calcium gluconate (60 mL IV) or 10% calcium chloride (20 mL IV) via central venous access. Repeat boluses can be given up to three times, and a calcium infusion may be necessary to maintain serum calcium levels above 2.0 mEq/L.
3. Atropine: Consider administering 0.6 mg every 2 minutes, up to a total of 1.8 mg. However, atropine is often ineffective in these cases.
4. High dose insulin – euglycemic therapy (HIET): The use of HIET in managing cardiovascular toxicity has evolved. It used to be a last-resort measure, but early administration is now increasingly recommended. This involves giving a bolus of short-acting insulin (1 U/kg) and 50 mL of 50% glucose IV (unless there is marked hyperglycemia). Therapy should be continued with a short-acting insulin/dextrose infusion. Glucose levels should be monitored frequently, and potassium should be replaced if levels drop below 2.5 mmol/L.
5. Vasoactive infusions: Catecholamines such as dopamine, adrenaline, and/or noradrenaline can be titrated to achieve the desired inotropic and chronotropic effects.
6. Sodium bicarbonate: Consider using sodium bicarbonate in cases where a severe metabolic acidosis develops.
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This question is part of the following fields:
- Pharmacology & Poisoning
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