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Question 1
Correct
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A 45-year-old man is brought into the Emergency Department by his wife after taking an overdose of paracetamol. The patient states that he “wants to end it all” and refuses to stay in hospital and receive treatment. His wife insists that he must be treated because “he is not thinking clearly”.
Which blood test is the earliest and most sensitive indicator of liver damage in paracetamol overdose?Your Answer: INR
Explanation:Paracetamol overdose is the most common overdose in the U.K. and is also the leading cause of acute liver failure. The liver damage occurs due to a metabolite of paracetamol called N-acetyl-p-benzoquinoneimine (NAPQI), which depletes the liver’s glutathione stores and directly harms liver cells. Severe liver damage and even death can result from an overdose of more than 12 g or > 150 mg/kg body weight.
The clinical manifestations of paracetamol overdose can be divided into four stages:
Stage 1 (0-24 hours): Patients may not show any symptoms, but common signs include nausea, vomiting, and abdominal discomfort.
Stage 2 (24-48 hours): Right upper quadrant pain and tenderness develop, along with the possibility of hypoglycemia and reduced consciousness.
Stage 3 (48-96 hours): Hepatic failure begins, characterized by jaundice, coagulopathy, and encephalopathy. Loin pain, haematuria, and proteinuria may indicate early renal failure.
Stage 4 (> 96 hours): Hepatic failure worsens progressively, leading to cerebral edema, disseminated intravascular coagulation (DIC), and ultimately death.
The earliest and most sensitive indicator of liver damage is a prolonged INR, which starts to rise approximately 24 hours after the overdose. Liver function tests (LFTs) typically remain normal until 18 hours after the overdose. However, AST and ALT levels then sharply increase and can exceed 10,000 units/L by 72-96 hours. Bilirubin levels rise more slowly and peak around 5 days.
The primary treatment for paracetamol overdose is acetylcysteine. Acetylcysteine is a highly effective antidote, but its efficacy diminishes rapidly if administered more than 8 hours after a significant ingestion. Ingestions exceeding 75 mg/kg are considered significant.
Acetylcysteine should be given based on a 4-hour level or administered empirically if the presentation occurs more than 8 hours after a significant overdose. If the overdose is staggered or the timing is uncertain, empirical treatment is also recommended. The treatment regimen is as follows:
– First dose: 150 mg/kg in 200 mL 5% glucose over 1 hour
– Second dose 50 mg/kg in 500 mL 5% glucose over 4 hours
– Third dose 100 mg/kg in 1000 mL 5% glucose over 16 hours -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 2
Incorrect
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A 42 year old male is brought into the emergency department by ambulance after confessing to taking a significant overdose of amitriptyline following a recent breakup. The patient later experiences a seizure. Which of the following anticonvulsant medications should not be used in TCA overdose?
Your Answer: Sodium valproate
Correct Answer: Phenytoin
Explanation:Patients who have taken an overdose of tricyclic antidepressants (TCAs) should not be given phenytoin.
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 3
Incorrect
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A 57-year-old man comes in with bothersome swelling in both ankles. This has developed since he began taking a new medication for high blood pressure a couple of weeks ago.
Which medication is the MOST likely culprit for this side effect?Your Answer: Bendroflumethiazide
Correct Answer: Amlodipine
Explanation:Amlodipine is a medication that belongs to the class of calcium-channel blockers and is often prescribed for the management of high blood pressure. One of the most frequently observed side effects of calcium-channel blockers is the swelling of the ankles. Additionally, individuals taking these medications may also experience other common side effects such as nausea, flushing, dizziness, sleep disturbances, headaches, fatigue, abdominal pain, and palpitations.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 4
Incorrect
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You evaluate a 35-year-old woman who has recently been diagnosed with epilepsy. She has been initiated on an anti-epileptic drug but has subsequently developed a tremor when assuming a certain posture.
Which INDIVIDUAL anti-epileptic medication is most likely to be accountable for this?Your Answer: Carbamazepine
Correct Answer: Sodium valproate
Explanation:Postural tremor is frequently seen as a neurological side effect in individuals taking sodium valproate. Additionally, a resting tremor may also manifest. It has been observed that around 25% of patients who begin sodium valproate therapy develop a tremor within the first year. Other potential side effects of sodium valproate include gastric irritation, nausea and vomiting, involuntary movements, temporary hair loss, weight gain in females, and impaired liver function.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 5
Correct
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A 25-year-old man has had discoloured teeth since taking a medication in his youth. Upon examination, visible greyish-brown horizontal stripes can be observed across all of his teeth.
Which SINGLE medication is most likely responsible for this?Your Answer: Doxycycline
Explanation:Tetracycline antibiotics, such as tetracycline and doxycycline, have the potential to cause staining on permanent teeth while they are still forming beneath the gum line. This staining occurs when the drug becomes calcified within the tooth during its development. It is important to note that children are vulnerable to tetracycline-related tooth staining until approximately the age of 8. Additionally, pregnant women should avoid taking tetracycline as it can affect the development of teeth in the unborn child.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 6
Incorrect
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A 32-year-old woman comes in with a complaint 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 LEAST likely to cause QT interval prolongation?Your Answer: Amitriptyline
Correct Answer: Metronidazole
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 7
Incorrect
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A 45 year old male is brought to the emergency department after developing a rash shortly after receiving a flu vaccination at the local clinic. On arrival it is noted that the patient's lips and throat have started to swell. You diagnose anaphylaxis and decide to administer epinephrine. What is the most suitable dosage?
Your Answer: 1000 micrograms (1 ml 1 in 1,000) adrenaline by intramuscular injection
Correct Answer: 500 micrograms (0.5ml 1 in 1,000) adrenaline by intramuscular injection
Explanation:The most suitable dosage of epinephrine for a patient experiencing anaphylaxis after a flu vaccination is 500 micrograms (0.5ml 1 in 1,000) adrenaline by intramuscular injection.
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 8
Incorrect
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A 15-year-old girl is prescribed prochlorperazine for symptoms of dizziness and nausea. Shortly after taking the medication, she experiences an acute dystonic reaction.
What is the most suitable treatment for this reaction? Choose ONE option only.Your Answer: Baclofen
Correct Answer: Procyclidine
Explanation:Drug-induced acute dystonic reactions are frequently seen in the Emergency Department. These reactions occur in approximately 0.5% to 1% of patients who have been administered metoclopramide or prochlorperazine. Procyclidine, an anticholinergic medication, has proven to be effective in treating drug-induced parkinsonism, akathisia, and acute dystonia. In emergency situations, a dose of 10 mg IV of procyclidine can be administered to promptly treat acute drug-induced dystonic reactions.
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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 62-year-old woman with hypercholesterolemia is prescribed simvastatin. After taking a course of antibiotics for a urinary tract infection, she experiences severe muscle pains. She is admitted to the hospital and diagnosed with acute renal failure, with a CK level of 1260 units/liter.
Which of the following antibiotics is she most likely to have been prescribed?Your Answer: Clarithromycin
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 10
Incorrect
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A 30-year-old woman develops cholestatic jaundice following an adverse drug effect of a new medication she has been prescribed.
Which medication is the LEAST likely to cause this adverse drug effect?Your Answer: Ibuprofen
Correct Answer: Isoniazid
Explanation:Isoniazid has the potential to induce acute hepatitis, but it is not considered a known cause of cholestatic jaundice. On the other hand, there are several drugs that have been identified as culprits for cholestatic jaundice. These include nitrofurantoin, erythromycin, cephalosporins, verapamil, NSAIDs, ACE inhibitors, tricyclic antidepressants, phenytoin, azathioprine, carbamazepine, oral contraceptive pills, diazepam, ketoconazole, and tamoxifen. It is important to be aware of these medications and their potential side effects in order to ensure patient safety.
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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 25-year-old woman arrives at the emergency department with swollen lips and a rash all over her body. According to her friend, she had recently consumed a sandwich. Anaphylaxis is suspected. You inquire about her medication use, and she presents a packet of propranolol. In addition to the usual treatment, which drug should be taken into consideration for this patient?
Your Answer: Calcium chloride
Correct Answer: Glucagon
Explanation:Glucagon may be an option for individuals experiencing anaphylaxis while taking beta blockers. However, it should not be chosen over Adrenaline as the primary treatment. Glucagon stimulates the production of cyclic AMP, which helps to increase heart contractility and heart rate, both of which are necessary during anaphylaxis. It is important to note that rapid administration of glucagon may lead to adverse effects such as nausea and vomiting.
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 12
Correct
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A 62-year-old woman comes in with a gout flare-up after starting a new blood pressure medication prescribed by her doctor.
Which of the following blood pressure medications is most likely causing this?Your Answer: Hydrochlorothiazide
Explanation:Thiazide diuretics, like bendroflumethiazide and hydrochlorothiazide, have the potential to raise levels of uric acid in the blood, which can worsen gout symptoms in individuals who are susceptible to the condition.
Other medications, such as diuretics, beta-blockers, ACE inhibitors, and non-losartan ARBs, are also linked to an increased risk of gout.
On the other hand, calcium-channel blockers like amlodipine and verapamil, as well as losartan, have been found to lower uric acid levels and are associated with a reduced risk of gout.
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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 25-year-old man is given a medication for a medical condition during the 2nd-trimester of his partner's pregnancy. As a result, the newborn experienced delayed onset labor and premature closure of the ductus arteriosus.
Which of the following medications is the most probable cause of these abnormalities?Your Answer: Gentamicin
Correct Answer: Diclofenac sodium
Explanation:The use of NSAIDs in the third trimester of pregnancy is linked to several risks. These risks include delayed onset of labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus, which is a condition where bilirubin causes 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 commonly encountered drugs that have adverse effects during pregnancy:
ACE inhibitors (e.g. ramipril): If given in the second and third trimester, these drugs can cause hypoperfusion, renal failure, and the oligohydramnios sequence.
Aminoglycosides (e.g. gentamicin): These drugs can cause ototoxicity and deafness.
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 a significant risk.
Benzodiazepines (e.g. diazepam): When given late in pregnancy, these drugs can cause 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 trimester, they can lead to fetal growth retardation.
Carbamazepine: This drug can cause hemorrhagic disease of the newborn and neural tube defects.
Chloramphenicol: Use of this drug can result in grey baby syndrome.
Corticosteroids: If given in the first trimester, corticosteroids may cause orofacial clefts.
Danazol: If given in the first trimester, this drug can cause masculinization of the female fetuses genitals.
Finasteride: Pregnant women should avoid handling finasteride. Crushed or broken tablets can be absorbed through the skin and affect male sex organ development.
Haloperidol: If given in the first trimester, this drug may cause limb malformations. If given in the third trimester, there is an increased risk of extrapyramidal symptoms in the neonate.
Heparin: Use of heparin during pregnancy can lead to maternal bleeding and thrombocytopenia.
Isoniazid: This drug can cause maternal liver damage
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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 woman becomes pregnant despite being on the oral contraceptive pill. Upon reviewing her medication, you discover that she has epilepsy and her anticonvulsant therapy was recently altered.
Which of the following anticonvulsants is most likely to impact the effectiveness of the oral contraceptive pill?Your Answer: Lamotrigine
Correct Answer: Phenytoin
Explanation:Enzyme-inducing anticonvulsants have been found to enhance the metabolism of ethinyl estradiol and progestogens. This increased breakdown diminishes the effectiveness of the oral contraceptive pill (OCP) in preventing pregnancy. Some examples of enzyme-inducing anticonvulsants include carbamazepine, phenytoin, phenobarbitol, and topiramate.
On the other hand, non-enzyme-inducing anticonvulsants are unlikely to have an impact on contraception. Some examples of these anticonvulsants are sodium valproate, clonazepam, gabapentin, levetiracetam, and piracetam.
It is important to note that lamotrigine, although classified as a non-enzyme-inducing anticonvulsant, requires special consideration. While there is no evidence suggesting that the OCP directly affects epilepsy, there is evidence indicating that it reduces the levels of lamotrigine in the bloodstream. This reduction in lamotrigine levels could potentially compromise seizure control and increase the likelihood of experiencing seizures.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 15
Incorrect
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A 35-year-old man with a history of anxiety and panic disorder has ingested an excessive amount of diazepam.
Which of the following antidotes is appropriate for cases of benzodiazepine poisoning?Your Answer:
Correct Answer: Flumazenil
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 16
Incorrect
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A 35-year-old patient with a history of schizophrenia comes in with side effects from a medication that he recently began taking for this condition. Upon examination, you observe that he is experiencing severe muscular rigidity, a decreased level of consciousness, and a body temperature of 40ºC.
Which of the following medications is most likely causing these symptoms?Your Answer:
Correct Answer: Chlorpromazine
Explanation:First-generation antipsychotics, also known as conventional or typical antipsychotics, are potent blockers of dopamine D2 receptors. However, these drugs also have varying effects on other receptors such as serotonin type 2 (5-HT2), alpha1, histaminic, and muscarinic receptors.
One of the major drawbacks of first-generation antipsychotics is their high incidence of extrapyramidal side effects. These include rigidity, bradykinesia, dystonias, tremor, akathisia, and tardive dyskinesia. Additionally, there is a rare but life-threatening reaction called neuroleptic malignant syndrome (NMS) that can occur with these medications. NMS is characterized by fever, muscle rigidity, altered mental status, and autonomic dysfunction. It typically occurs shortly after starting or increasing the dose of a neuroleptic medication.
In contrast, second-generation antipsychotics, also known as novel or atypical antipsychotics, have a lower risk of extrapyramidal side effects and NMS compared to their first-generation counterparts. However, they are associated with higher rates of metabolic effects and weight gain.
It is important to differentiate serotonin syndrome from NMS as they share similar features. Serotonin syndrome is most commonly caused by serotonin-specific reuptake inhibitors.
Here are some commonly encountered examples of first- and second-generation antipsychotics:
First-generation:
– Chlopromazine
– Haloperidol
– Fluphenazine
– TrifluoperazineSecond-generation:
– Clozapine
– Olanzapine
– Quetiapine
– Risperidone
– Aripiprazole -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 17
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:
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 18
Incorrect
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A 67 year old individual experiences muscle rigidity and fever after being intubated. Your supervisor instructs you to administer dantrolene. What is the mechanism of action of dantrolene?
Your Answer:
Correct Answer: Inhibits calcium efflux from the sarcoplasmic reticulum
Explanation:Dantrolene works by blocking the release of calcium ions from the sarcoplasmic reticulum in skeletal muscle cells. This reduces the amount of calcium available to bind to troponin on actin filaments, which in turn decreases the muscle’s ability to contract and reduces energy usage.
Further Reading:
Malignant hyperthermia is a rare and life-threatening syndrome that can be triggered by certain medications in individuals who are genetically susceptible. The most common triggers are suxamethonium and inhalational anaesthetic agents. The syndrome is caused by the release of stored calcium ions from skeletal muscle cells, leading to uncontrolled muscle contraction and excessive heat production. This results in symptoms such as high fever, sweating, flushed skin, rapid heartbeat, and muscle rigidity. It can also lead to complications such as acute kidney injury, rhabdomyolysis, and metabolic acidosis. Treatment involves discontinuing the trigger medication, administering dantrolene to inhibit calcium release and promote muscle relaxation, and managing any associated complications such as hyperkalemia and acidosis. Referral to a malignant hyperthermia center for further investigation is also recommended.
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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 35-year-old woman is being evaluated after a benzodiazepine overdose. As part of her treatment, she is given a dose of flumazenil.
Which SINGLE statement about flumazenil is NOT true?Your Answer:
Correct Answer: The maximum dose is 10 mg per hour
Explanation:Flumazenil is a specific antagonist for benzodiazepines that can be beneficial in certain situations. It acts quickly, taking less than 1 minute to take effect, but its effects are short-lived and only last for less than 1 hour. The recommended dosage is 200 μg every 1-2 minutes, with a maximum dose of 3mg per hour.
It is important to avoid using Flumazenil if the patient is dependent on benzodiazepines or is taking tricyclic antidepressants. This is because it can trigger a withdrawal syndrome in these individuals, potentially leading to seizures or cardiac arrest.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 20
Incorrect
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A 42-year-old woman with a long history of anxiety presents having taken a deliberate overdose of the medication she takes for a thyroid condition. She informs you that the medication she takes for this condition is levothyroxine 100 mcg. She consumed the medication approximately 30 minutes ago but was promptly discovered by her husband, who quickly brought her to the Emergency Department.
Which of the following tests will be most beneficial initially?Your Answer:
Correct Answer: Arterial blood gas
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 21
Incorrect
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A 68 year old patient with dementia is brought into the emergency department by a caregiver due to a suspected accidental overdose. The caregiver reports finding several of the patient's medication bottles with multiple tablets missing. An ECG is conducted and reveals a prolonged QT interval. The caregiver presents you with the medication containers. Which of the following medications is the most probable culprit for the prolonged QT interval?
Your Answer:
Correct Answer: Citalopram
Explanation:Antipsychotics and antidepressants are drugs that are known to cause QT prolongation, which is a potentially dangerous heart rhythm abnormality. Similarly, SSRIs and other antidepressants are also associated with QT prolongation. On the other hand, beta-blockers like bisoprolol are used to shorten the QT interval and are considered as a treatment option for long QT syndrome. However, it’s important to note that sotalol, although classified as a beta blocker, acts differently by blocking potassium channels. This unique mechanism of action makes sotalol a class III anti-arrhythmic agent and may result in QT interval prolongation.
Further Reading:
Long QT syndrome (LQTS) is a condition characterized by a prolonged QT interval on an electrocardiogram (ECG), which represents abnormal repolarization of the heart. LQTS can be either acquired or congenital. Congenital LQTS is typically caused by gene abnormalities that affect ion channels responsible for potassium or sodium flow in the heart. There are 15 identified genes associated with congenital LQTS, with three genes accounting for the majority of cases. Acquired LQTS can be caused by various factors such as certain medications, electrolyte imbalances, hypothermia, hypothyroidism, and bradycardia from other causes.
The normal QTc values, which represent the corrected QT interval for heart rate, are typically less than 450 ms for men and less than 460ms for women. Prolonged QTc intervals are considered to be greater than these values. It is important to be aware of drugs that can cause QT prolongation, as this can lead to potentially fatal arrhythmias. Some commonly used drugs that can cause QT prolongation include antimicrobials, antiarrhythmics, antipsychotics, antidepressants, antiemetics, and others.
Management of long QT syndrome involves addressing any underlying causes and using beta blockers. In some cases, an implantable cardiac defibrillator (ICD) may be recommended for patients who have experienced recurrent arrhythmic syncope, documented torsades de pointes, previous ventricular tachyarrhythmias or torsades de pointes, previous cardiac arrest, or persistent syncope. Permanent pacing may be used in patients with bradycardia or atrioventricular nodal block and prolonged QT. Mexiletine is a treatment option for those with LQT3. Cervicothoracic sympathetic denervation may be considered in patients with recurrent syncope despite beta-blockade or in those who are not ideal candidates for an ICD. The specific treatment options for LQTS depend on the type and severity of the condition.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 22
Incorrect
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A 30-year-old man is diagnosed with a psychiatric disorder during the 2nd-trimester of his partner's pregnancy and is started on medication. As a result of this treatment, the newborn experiences a discontinuation syndrome and persistent pulmonary hypertension.
Which of the following medications is the most probable cause of these abnormalities?Your Answer:
Correct Answer: Fluoxetine
Explanation:During the third trimester of pregnancy, the use of selective serotonin reuptake inhibitors (SSRIs) has been associated with a discontinuation syndrome and persistent pulmonary hypertension of the newborn. It is important to be aware of the adverse effects of various drugs during pregnancy. For example, ACE inhibitors like ramipril, if given in the second and third trimester, can cause hypoperfusion, renal failure, and the oligohydramnios sequence. Aminoglycosides such as gentamicin can lead to ototoxicity and deafness. High doses of aspirin can result in 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. Late administration of benzodiazepines like diazepam during pregnancy can cause respiratory depression and a neonatal withdrawal syndrome. Calcium-channel blockers, if given in the first trimester, may cause phalangeal abnormalities, while their use in the second and third trimester can lead to fetal growth retardation. Carbamazepine has been associated with hemorrhagic disease of the newborn and neural tube defects. Chloramphenicol can cause grey baby syndrome. Corticosteroids, if given in the first trimester, may cause orofacial clefts. Danazol, if administered in the first trimester, can result in masculinization of the female fetuses genitals. Pregnant women should avoid handling crushed or broken tablets of finasteride as it can be absorbed through the skin and affect male sex organ development. Haloperidol, if given in the first trimester, may cause limb malformations, while its use in the third trimester increases the risk of extrapyramidal symptoms in the neonate. Heparin can lead to maternal bleeding and thrombocytopenia. Isoniazid can cause maternal liver damage and neuropathy and seizures in the neonate. Isotretinoin carries a high risk of teratogenicity, including multiple congenital malformations, spontaneous abortion, and intellectual disability. The use of lithium in the first trimester increases the risk of fetal cardiac malformations, while its use in the second and third trimesters can result in hypotonia, lethargy, feeding problems, hypothyroidism, goiter, and nephrogenic diabetes insipidus.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 23
Incorrect
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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:
Correct 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 24
Incorrect
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A 65-year-old patient comes in after a chronic overdose of digoxin. She complains of nausea, extreme fatigue, and overall feeling unwell.
What is the indication for using DigiFab in this patient?Your Answer:
Correct Answer: Significant gastrointestinal symptoms
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 25
Incorrect
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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:
Correct 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 26
Incorrect
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A 62-year-old woman comes in with a gout flare-up after starting a new antihypertensive medication prescribed by her doctor. Which of the following antihypertensives is the LEAST likely to be the cause?
Your Answer:
Correct Answer: Losartan
Explanation:Thiazide diuretics, like bendroflumethiazide and hydrochlorothiazide, have the potential to raise levels of uric acid in the blood, which can worsen gout symptoms in individuals who are susceptible to the condition.
Other medications, such as diuretics, beta-blockers, ACE inhibitors, and non-losartan ARBs, are also linked to an increased risk of gout.
On the other hand, calcium-channel blockers like amlodipine and verapamil, as well as losartan, have been found to lower uric acid levels and are associated with a reduced risk of gout.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 27
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:
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 28
Incorrect
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A patient with a known history of asthma presents with symptoms of theophylline toxicity after starting a new medication.
Which of the following drugs is most likely causing this interaction?Your Answer:
Correct Answer: Fluconazole
Explanation:Theophylline, a medication commonly used to treat respiratory conditions, can be affected by certain drugs, either increasing or decreasing its plasma concentration and half-life. Drugs that can increase the plasma concentration of theophylline include calcium channel blockers like verapamil, cimetidine, fluconazole, macrolides such as erythromycin, methotrexate, and quinolones like ciprofloxacin. On the other hand, drugs like carbamazepine, phenobarbitol, phenytoin (and fosphenytoin), rifampicin, and St. John’s wort can decrease the plasma concentration of theophylline. It is important to be aware of these interactions when prescribing or taking theophylline to ensure its effectiveness and avoid potential side effects.
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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 60-year-old man has accidentally consumed an excessive amount of amitriptyline tablets and is currently experiencing toxic side effects.
Which of the following mechanisms is NOT involved in mediating these toxic effects?Your Answer:
Correct Answer: Opening of potassium channels
Explanation:Tricyclic antidepressant (TCA) overdose is a significant problem in cases of drug overdose and is one of the most common causes of fatal drug poisoning. Any overdose of amitriptyline that exceeds 10 mg/kg has the potential to be life-threatening. If the overdose surpasses 30 mg/kg, it will lead to severe toxicity, cardiotoxicity, and coma.
The toxic effects of TCAs are caused by various pharmacological actions. These include anticholinergic effects, direct blocking of alpha-adrenergic receptors, inhibition of noradrenaline reuptake at the preganglionic synapse, blockade of sodium channels, and blockade of potassium channels.
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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 25-year-old man presents having ingested an overdose of an unknown substance. He is drowsy and slurring his speech. His vital signs are as follows: heart rate 116 beats per minute, blood pressure 91/57 mmHg, oxygen saturation 96% on room air. Glasgow Coma Scale score is 11 out of 15. The results of his arterial blood gas (ABG) on room air are as follows:
pH: 7.24
pO2: 9.4 kPa
PCO2: 3.3 kPa
HCO3-: 22 mmol/l
Na+: 143 mmol/l
Cl–: 99 mmol/l
Lactate: 5 IU/l
Which SINGLE statement regarding this patient is true?Your Answer:
Correct Answer: Her anion gap is elevated
Explanation:Arterial blood gas (ABG) interpretation is essential for evaluating a patient’s respiratory gas exchange and acid-base balance. The normal values on an ABG may slightly vary between analyzers, but generally, they fall within the following ranges:
pH: 7.35 – 7.45
pO2: 10 – 14 kPa
PCO2: 4.5 – 6 kPa
HCO3-: 22 – 26 mmol/l
Base excess: -2 – 2 mmol/lIn this particular case, the patient’s history indicates an overdose. However, there is no immediate need for intubation as her Glasgow Coma Scale (GCS) score is 11/15, and she can speak, albeit with slurred speech, indicating that she can maintain her own airway.
The relevant ABG findings are as follows:
– Mild hypoxia
– Decreased pH (acidaemia)
– Low PCO2
– Normal bicarbonate
– Elevated lactateThe anion gap is a measure of the concentration of unmeasured anions in the plasma. It is calculated by subtracting the primary measured cations from the primary measured anions in the serum. The reference range for anion gap varies depending on the methodology used, but it is typically between 8 to 16 mmol/L.
In this case, the patient’s anion gap can be calculated using the formula:
Anion gap = [Na+] – [Cl-] – [HCO3-]
Using the given values:
Anion gap = [143] – [99] – [22]
Anion gap = 22Therefore, it is evident that she has a raised anion gap metabolic acidosis. It is likely a type A lactic acidosis resulting from tissue hypoxia and hypoperfusion. Some potential causes of type A and type B lactic acidosis include:
Type A lactic acidosis:
– Shock (including septic shock)
– Left ventricular failure
– Severe anemia
– Asphyxia
– Cardiac arrest
– Carbon monoxide poisoning
– Respiratory failure
– Severe asthma and COPD
– Regional hypoperfusionType B lactic acidosis:
– Renal failure
– Liver failure
– Sepsis (non-hypoxic sepsis)
– Thiamine deficiency
– Al -
This question is part of the following fields:
- Pharmacology & Poisoning
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