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Question 1
Correct
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A 25-year-old student is brought to the clinic by his companions as he appears confused. They mention that he has been experiencing headaches for the past few weeks. During the examination, he has a low-grade fever and his mucosa is unusually pink. What is the probable diagnosis?
Your Answer: Carbon monoxide poisoning
Explanation:Typical symptoms of carbon monoxide poisoning include confusion and pink mucosae, with a low-grade fever being present in only a small number of cases.
Understanding Carbon Monoxide Poisoning
Carbon monoxide poisoning occurs when carbon monoxide, a toxic gas, is inhaled and binds to haemoglobin and myoglobin in the body, resulting in tissue hypoxia. This leads to a left-shift of the oxygen dissociation curve, causing a decrease in oxygen saturation of haemoglobin. In the UK, there are approximately 50 deaths per year from accidental carbon monoxide poisoning.
Symptoms of carbon monoxide toxicity include headache, nausea and vomiting, vertigo, confusion, and subjective weakness. Severe toxicity can result in pink skin and mucosae, hyperpyrexia, arrhythmias, extrapyramidal features, coma, and even death.
To diagnose carbon monoxide poisoning, pulse oximetry may not be reliable due to similarities between oxyhaemoglobin and carboxyhaemoglobin. Therefore, a venous or arterial blood gas should be taken to measure carboxyhaemoglobin levels. Non-smokers typically have levels below 3%, while smokers have levels below 10%. Symptomatic patients have levels between 10-30%, and severe toxicity is indicated by levels above 30%. An ECG may also be useful to check for cardiac ischaemia.
In the emergency department, patients with suspected carbon monoxide poisoning should receive 100% high-flow oxygen via a non-rebreather mask. This decreases the half-life of carboxyhemoglobin and should be administered as soon as possible, with treatment continuing for a minimum of six hours. Target oxygen saturations are 100%, and treatment is generally continued until all symptoms have resolved. For more severe cases, hyperbaric oxygen therapy may be considered, as it has been shown to have better long-term outcomes than standard oxygen therapy. Indications for hyperbaric oxygen therapy include loss of consciousness, neurological signs other than headache, myocardial ischaemia or arrhythmia, and pregnancy.
Overall, understanding the pathophysiology, symptoms, and management of carbon monoxide poisoning is crucial in preventing and treating this potentially deadly condition.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 2
Correct
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You have diagnosed a 68-year-old woman with chronic kidney disease stage G3b (estimated glomerular filtration rate or eGFR = 32 ml/min per 1.73m2) with a lower urinary tract infection (UTI) confirmed on mid-stream urine culture and sensitivity:
Escherichia coli: heavy growth
resistant to trimethoprim
sensitive to nitrofurantoin, amoxicillin, co-amoxiclav
Which of the following antibiotics is it most appropriate to prescribe?Your Answer: Amoxicillin
Explanation:Choosing the Best Antibiotic for a UTI: A Case Study
A patient presents with symptoms of a lower urinary tract infection (UTI) and a urine culture confirms the presence of bacteria. However, the causative organism is resistant to the first-line agents nitrofurantoin and trimethoprim, and the patient’s renal function contraindicates the use of nitrofurantoin.
The next best option would be to use amoxicillin, as long as the organism is susceptible to it. Other suitable options include pivmecillinam and fosfomycin, if there is a high risk of resistance. Ciprofloxacin and co-amoxiclav are not appropriate for the treatment of a lower UTI.
In summary, choosing the best antibiotic for a UTI requires consideration of the patient’s renal function and the susceptibility of the causative organism. Amoxicillin, pivmecillinam, and fosfomycin are suitable alternatives when first-line agents are not effective.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 3
Correct
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Which one of the following investigations is essential prior to initiating anti-tuberculosis treatment in elderly patients?
Your Answer: Liver functions tests
Explanation:The management of tuberculosis has been outlined in guidelines by the British Thoracic Society. It is recommended that liver function tests are conducted in all cases and monitored during treatment. Prior to starting ethambutol, it is important to check visual acuity and renal function.
Side-Effects and Mechanism of Action of Tuberculosis Drugs
Rifampicin is a drug that inhibits bacterial DNA dependent RNA polymerase, which prevents the transcription of DNA into mRNA. However, it is a potent liver enzyme inducer and can cause hepatitis, orange secretions, and flu-like symptoms.
Isoniazid, on the other hand, inhibits mycolic acid synthesis. It can cause peripheral neuropathy, which can be prevented with pyridoxine (Vitamin B6). It can also cause hepatitis and agranulocytosis. Additionally, it is a liver enzyme inhibitor.
Pyrazinamide is converted by pyrazinamidase into pyrazinoic acid, which in turn inhibits fatty acid synthase (FAS) I. However, it can cause hyperuricaemia, leading to gout, as well as arthralgia, myalgia, and hepatitis.
Lastly, Ethambutol inhibits the enzyme arabinosyl transferase, which polymerizes arabinose into arabinan. It can cause optic neuritis, so it is important to check visual acuity before and during treatment. Additionally, the dose needs adjusting in patients with renal impairment.
In summary, these tuberculosis drugs have different mechanisms of action and can cause various side-effects. It is important to monitor patients closely and adjust treatment accordingly to ensure the best possible outcomes.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 4
Correct
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A 21-year-old female inpatient on the surgical ward developed sudden uncontrollable eye movements, with prolonged involuntary upward deviation of the eyes.
Which of the following drugs is most likely to be responsible?Your Answer: Metoclopramide
Explanation:Understanding the Causes of Dystonic Reactions: A Comparison of Common Drugs
Metoclopramide, carbamazepine, cyclopentolate, lidocaine, and procyclidine are all drugs that can cause various side effects, including disturbances in eye movement. However, when it comes to dystonic reactions, metoclopramide and procyclidine are the most likely culprits. Metoclopramide, commonly used for nausea and vomiting, can induce acute dystonic reactions involving facial and skeletal muscle spasms and oculogyric crises. On the other hand, procyclidine, an anti-muscarinic drug, is useful in the immediate treatment of a drug-induced oculogyric crisis. Understanding the differences between these drugs and their potential side effects is crucial in providing appropriate treatment for patients experiencing dystonic reactions.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 5
Correct
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A 61-year-old man with a history of type 2 diabetes mellitus and benign prostatic hypertrophy experiences urinary retention and an acute kidney injury. Which medication should be discontinued?
Your Answer: Metformin
Explanation:Due to the risk of lactic acidosis, metformin should be discontinued as the patient has developed an acute kidney injury. Additionally, in the future, it may be necessary to discontinue paroxetine as SSRIs can exacerbate urinary retention.
Metformin is a medication commonly used to treat type 2 diabetes mellitus. It belongs to a class of drugs called biguanides and works by activating the AMP-activated protein kinase (AMPK), which increases insulin sensitivity and reduces hepatic gluconeogenesis. Additionally, it may decrease the absorption of carbohydrates in the gastrointestinal tract. Unlike other diabetes medications, such as sulphonylureas, metformin does not cause hypoglycemia or weight gain, making it a first-line treatment option, especially for overweight patients. It is also used to treat polycystic ovarian syndrome and non-alcoholic fatty liver disease.
While metformin is generally well-tolerated, gastrointestinal side effects such as nausea, anorexia, and diarrhea are common and can be intolerable for some patients. Reduced absorption of vitamin B12 is also a potential side effect, although it rarely causes clinical problems. In rare cases, metformin can cause lactic acidosis, particularly in patients with severe liver disease or renal failure. However, it is important to note that lactic acidosis is now recognized as a rare side effect of metformin.
There are several contraindications to using metformin, including chronic kidney disease, recent myocardial infarction, sepsis, acute kidney injury, severe dehydration, and alcohol abuse. Additionally, metformin should be discontinued before and after procedures involving iodine-containing x-ray contrast media to reduce the risk of contrast nephropathy.
When starting metformin, it is important to titrate the dose slowly to reduce the incidence of gastrointestinal side effects. If patients experience intolerable side effects, modified-release metformin may be considered as an alternative.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 6
Correct
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To prevent adverse drug effects, which drug from the list below should have their serum levels monitored?
Select the SINGLE most important drug from the list below.Your Answer: Theophylline
Explanation:Monitoring Medications: Guidelines for Serum Level and Function Tests
Theophylline: To avoid toxicity, serum theophylline levels should be monitored due to its narrow therapeutic window. A concentration of 10-20 mg/l is required for bronchodilatation, but adverse effects can occur within this range and increase at concentrations >20 mg/l. Plasma theophylline concentration should be measured 5 days after starting oral treatment and at least 3 days after any dose adjustment.
Carbimazole: The maintenance dose for this anti-thyroid drug is determined by measuring fT4 and TSH levels.
Warfarin: The INR, not serum level monitoring, is used to assess the effect of this anticoagulant.
Rifampicin: Renal and hepatic function should be checked before treatment. Further checks are necessary only if the patient develops fever, malaise, vomiting, jaundice, or unexplained deterioration during treatment. However, liver function and full blood count should be monitored on prolonged therapy.
Cyclophosphamide: Side effects from this medication include bone marrow suppression and haemorrhagic cystitis, related to the cumulative medication dose. A full blood count and urinalysis should be monitored regularly in patients taking this medication.
Guidelines for Monitoring Medications: Serum Levels and Function Tests
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 7
Incorrect
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Prolonged use of which drug can result in tachyphylaxis, which is an acute and sudden decrease in response to a drug after its administration, leading to a rapid and short-term onset of drug tolerance?
Your Answer: Amiodarone
Correct Answer: Xylometazoline (eg Sudafed® nasal spray)
Explanation:Common Drugs and Tachyphylaxis: Understanding the Risk
Nasal decongestants, such as xylometazoline, are often used to relieve nasal congestion. However, prolonged use can lead to rebound congestion, known as rhinitis medicamentosa. Amiodarone, an antiarrhythmic drug, has a long half-life and potential for drug interactions even after treatment has stopped. Metronidazole, an antimicrobial drug, can be absorbed systemically and may interact with other medications. Naproxen, a non-steroidal anti-inflammatory drug, has no evidence of tachyphylaxis. Phenoxymethylpenicillin, an antibiotic, is not associated with tachyphylaxis. Understanding the risk of tachyphylaxis with common drugs is important for safe and effective use.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 8
Correct
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You are requested to assess an 80-year-old man who was admitted to the hospital five days ago due to community-acquired pneumonia. The patient has a medical history of type 2 diabetes mellitus, angina, chronic obstructive pulmonary disease (COPD), and spinal stenosis.
Despite receiving optimal treatment on the ward, including IV co-amoxiclav, the patient's condition has continued to deteriorate. He currently scores 11 on the Glasgow Coma Scale, and his pupils are reactive to light and measure 3 mm bilaterally. He has been unable to take his morning medications, which include morphine sulphate modified release (Zomorph) 30mg twice daily, oramorph 10mg as required, and metoclopramide 10 mg three times a day. In the past 24 hours, he has used 4 doses of PRN oramorph.
During the consultant ward round, it is decided that the patient should receive end-of-life care. He is currently comfortable, with no signs of hallucinations, pruritus, or myoclonus. The nurse requests that you convert his medications to a syringe driver.
What medications will you prescribe?Your Answer: Metoclopramide 30mg s/c + morphine 50mg s/c
Explanation:Palliative care prescribing for pain is guided by NICE and SIGN guidelines. NICE recommends starting treatment with regular oral modified-release or immediate-release morphine, with immediate-release morphine for breakthrough pain. Laxatives should be prescribed for all patients initiating strong opioids, and antiemetics should be offered if nausea persists. Drowsiness is usually transient, but if it persists, the dose should be adjusted. SIGN advises that the breakthrough dose of morphine is one-sixth the daily dose, and all patients receiving opioids should be prescribed a laxative. Opioids should be used with caution in patients with chronic kidney disease, and oxycodone is preferred to morphine in patients with mild-moderate renal impairment. Metastatic bone pain may respond to strong opioids, bisphosphonates, or radiotherapy, and all patients should be considered for referral to a clinical oncologist for further treatment. When increasing the dose of opioids, the next dose should be increased by 30-50%. Conversion factors between opioids are also provided. Opioid side-effects are usually transient, such as nausea and drowsiness, but constipation can persist. In addition to strong opioids, bisphosphonates, and radiotherapy, denosumab may be used to treat metastatic bone pain.
Overall, the guidelines recommend starting with regular oral morphine and adjusting the dose as needed. Laxatives should be prescribed to prevent constipation, and antiemetics may be needed for nausea. Opioids should be used with caution in patients with chronic kidney disease, and oxycodone is preferred in patients with mild-moderate renal impairment. Metastatic bone pain may respond to strong opioids, bisphosphonates, or radiotherapy, and referral to a clinical oncologist should be considered. Conversion factors between opioids are provided, and the next dose should be increased by 30-50% when adjusting the dose. Opioid side-effects are usually transient, but constipation can persist. Denosumab may also be used to treat metastatic bone pain.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 9
Correct
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A 28-year-old woman who is 16 weeks' pregnant complains of frequent urination. Urinalysis confirms the presence of nitrites and leukocytes.
What is the most appropriate antibiotic to prescribe?Your Answer: Nitrofurantoin
Explanation:Management of Urinary Tract Infections in Pregnancy: Antibiotic Options and Guidelines
Urinary tract infections (UTIs) are common during pregnancy and require prompt treatment to prevent complications. The current UK antimicrobial guidelines recommend nitrofurantoin as the first-line treatment for UTIs in pregnancy, with amoxicillin as an alternative if the microorganism is susceptible to it. Trimethoprim should be avoided due to its teratogenicity risk, while ciprofloxacin is only used for specific cases. Vancomycin is reserved for severe cases of Clostridium difficile infection. Symptomatic relief with paracetamol can also be offered. Urine cultures should be sent before starting empirical antibiotic treatment and as a test of cure after treatment completion. Follow-up is necessary to check treatment response and culture results. This article provides a comprehensive overview of the antibiotic options and guidelines for managing UTIs in pregnancy.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 10
Incorrect
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An 80-year-old man comes in for a routine check-up with his General Practitioner. He has a medical history of atrial fibrillation, type II diabetes, depression, and chronic alcohol abuse. His current medications include warfarin 3 mg once daily, ramipril 2.5 mg once daily, bisoprolol 2 mg once daily, erythromycin 500 mg four times daily (day five of a 7-day course for cellulitis on the leg), and sertraline 50 mg once daily (started four weeks ago). He is allergic to penicillin. His blood work shows an INR of 6.5 (target 2.0-3.0). What is the most likely reason for his elevated INR?
Your Answer: Erythromycin is a P450 inducer
Correct Answer: Erythromycin is a P450 inhibiter
Explanation:The patient is taking erythromycin for cellulitis, which inhibits the cytochrome P450 enzymes responsible for breaking down drugs like warfarin and statins. As a result, the effects of warfarin are potentiated, leading to a higher than expected INR. Bisoprolol is unlikely to have contributed to the change in INR as it does not affect the P450 system. Chronic alcohol abuse can induce P450 enzymes, but this would cause a lower INR. Erythromycin is an inhibitor, not an inducer, of P450 enzymes. Sertraline, though recently started, is also an enzyme inhibitor and cannot explain the high INR.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 11
Incorrect
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A senior citizen who is taking digoxin asks you about the toxic effects of digoxin therapy, having read about it on the internet.
Which of the following is associated with digoxin toxicity?Your Answer: Gum hypertrophy
Correct Answer: Premature ventricular beats
Explanation:Understanding Digoxin Toxicity: Symptoms and Risk Factors
Digoxin toxicity can occur suddenly in cases of overdose or gradually during long-term treatment. It is a common issue among elderly patients and is often associated with risk factors such as hypokalemia, hypomagnesemia, and hypercalcemia. The most common and earliest dysrhythmia in digoxin toxicity is the finding of premature ventricular beats on an ECG, along with sinus bradycardia. Other ECG changes may include depressed conduction, bigeminal and trigeminal rhythms, ventricular bigeminy, and bidirectional ventricular tachycardia. Hair loss is not associated with digoxin toxicity, but gum/gingival hypertrophy can be caused by other drugs. Loss of appetite, vomiting, anorexia, and fatigue are common symptoms reported by patients. It is important to understand the symptoms and risk factors associated with digoxin toxicity to ensure proper treatment and management.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 12
Incorrect
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A 55-year-old man has an HbA1c of 54 mmol/mol after 3 months of lifestyle changes, following a previous reading of HbA1c of 52 mmol/mol. You suggest that he should begin taking metformin standard release in addition to lifestyle interventions. He has normal renal function and no other medical issues. You inform him of the possibility of gastrointestinal discomfort.
What is the typical duration before considering increasing the dosage to alleviate these symptoms for this patient?Your Answer: 14 days
Correct Answer: 7 days
Explanation:It is recommended to increase the dose of metformin gradually, with a minimum of one week between each increase.
Metformin is a medication commonly used to treat type 2 diabetes mellitus. It belongs to a class of drugs called biguanides and works by activating the AMP-activated protein kinase (AMPK), which increases insulin sensitivity and reduces hepatic gluconeogenesis. Additionally, it may decrease the absorption of carbohydrates in the gastrointestinal tract. Unlike other diabetes medications, such as sulphonylureas, metformin does not cause hypoglycemia or weight gain, making it a first-line treatment option, especially for overweight patients. It is also used to treat polycystic ovarian syndrome and non-alcoholic fatty liver disease.
While metformin is generally well-tolerated, gastrointestinal side effects such as nausea, anorexia, and diarrhea are common and can be intolerable for some patients. Reduced absorption of vitamin B12 is also a potential side effect, although it rarely causes clinical problems. In rare cases, metformin can cause lactic acidosis, particularly in patients with severe liver disease or renal failure. However, it is important to note that lactic acidosis is now recognized as a rare side effect of metformin.
There are several contraindications to using metformin, including chronic kidney disease, recent myocardial infarction, sepsis, acute kidney injury, severe dehydration, and alcohol abuse. Additionally, metformin should be discontinued before and after procedures involving iodine-containing x-ray contrast media to reduce the risk of contrast nephropathy.
When starting metformin, it is important to titrate the dose slowly to reduce the incidence of gastrointestinal side effects. If patients experience intolerable side effects, modified-release metformin may be considered as an alternative.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 13
Correct
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A 65-year-old woman with atrial fibrillation and hypertension is prescribed amiodarone.
Which of the following blood tests is crucial for monitoring amiodarone use?Your Answer: LFTs, TFTs (6-monthly)
Explanation:Drug Monitoring in Primary Care
Drug monitoring is an essential aspect of patient care, particularly for medications with potential side effects. In primary care, drug monitoring is becoming increasingly common, especially for patients managed through shared-care with specialty care.
Amiodarone is a medication that requires ongoing monitoring for potential side effects, including pulmonary toxicity, thyroid dysfunction, abnormal liver function, and corneal microdeposits. Monitoring includes checking LFTs and TFTs every six months, a chest radiograph and ECG every 12 months, and an annual ophthalmological examination.
Azathioprine requires monitoring of FBC and LFTs every three months, while lithium requires monitoring of U&Es, TFTs, and lithium plasma levels every six months. Methotrexate requires monitoring of FBC, U&Es, and LFTs every two to three months.
In conclusion, drug monitoring is crucial in primary care to ensure patient safety and prevent potential adverse effects. Regular monitoring of blood tests can help detect any changes in a patient’s health and allow for timely intervention.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 14
Correct
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A 30-year-old male is brought to the emergency department after being found unconscious on the street with a syringe and used pack of oxycodone and alprazolam nearby. Upon examination, he is lethargic with pinpoint pupils, reduced bowel sounds, and fresh needle marks on his right arm. His vital signs are: blood pressure 110/70 mmHg, heart rate 55/min, oxygen saturation of 95% on room air, temperature 36ºC, and respiratory rate of 5 breaths per minute. His blood glucose level is 8 mmol/L. What is the most appropriate management for this patient?
Your Answer: Naloxone
Explanation:The individual displays classic symptoms of acute opioid overdose, including slow breathing, constricted pupils, and changes in consciousness.
The management of overdoses and poisonings involves specific treatments for each toxin. For paracetamol overdose, activated charcoal is recommended if ingested within an hour, followed by N-acetylcysteine or liver transplantation if necessary. Salicylate overdose can be managed with urinary alkalinization using IV bicarbonate or haemodialysis. Opioid/opiate overdose can be treated with naloxone, while benzodiazepine overdose can be treated with flumazenil in severe cases. Tricyclic antidepressant overdose may require IV bicarbonate to reduce the risk of seizures and arrhythmias, but class 1a and class Ic antiarrhythmics should be avoided. Lithium toxicity may respond to volume resuscitation with normal saline or haemodialysis in severe cases. Warfarin overdose can be treated with vitamin K or prothrombin complex, while heparin overdose can be treated with protamine sulphate. Beta-blocker overdose may require atropine or glucagon. Ethylene glycol poisoning can be managed with fomepizole or ethanol, while methanol poisoning can be treated with the same. Organophosphate insecticide poisoning can be treated with atropine, and digoxin overdose can be treated with digoxin-specific antibody fragments. Iron overdose can be managed with desferrioxamine, and lead poisoning can be treated with dimercaprol or calcium edetate. Carbon monoxide poisoning can be managed with 100% oxygen or hyperbaric oxygen, while cyanide poisoning can be treated with hydroxocobalamin or a combination of amyl nitrite, sodium nitrite, and sodium thiosulfate.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 15
Incorrect
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An 80-year-old man is admitted to the orthogeriatric ward following a femoral fracture from a fall. He has a medical history of diabetes mellitus type 2, benign prostate hyperplasia, and severe hay fever. After a few days, the patient reports experiencing suprapubic discomfort and difficulty urinating. Which medication is the most probable cause of his symptoms?
Your Answer: Loratadine
Correct Answer: Codeine
Explanation:Urinary retention is a common side effect of opioid analgesia, including the use of codeine. Other medications that can cause this issue include tricyclic antidepressants, anticholinergics, and NSAIDs. Doxazosin, an alpha-blocker, is often prescribed to improve symptoms of benign prostatic hyperplasia and reduce resistance to bladder outflow. Duloxetine, an SSRI used to treat diabetic neuropathy, does not typically cause urinary retention. Finasteride, a 5-alpha reductase inhibitor, is a second-line treatment for benign prostatic hyperplasia when alpha-blockers are not effective, as it reduces prostatic bulk.
Drugs that can cause urinary retention
Urinary retention is a condition where a person is unable to empty their bladder completely. This can be caused by various factors, including certain medications. Some drugs that may lead to urinary retention include tricyclic antidepressants like amitriptyline, anticholinergics such as antipsychotics and antihistamines, opioids, NSAIDs, and disopyramide. These drugs can affect the muscles that control the bladder, making it difficult to urinate.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 16
Incorrect
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A 59-year-old man visits his doctor with a complaint of hearing difficulties. He reports that he can no longer hear the television from his couch and struggles to hear his wife when she speaks from another room. Upon examination, his ears appear normal and otoscopy reveals no abnormalities. He denies experiencing any other symptoms. The patient has a complicated medical history, including chronic obstructive pulmonary disease, hypertension, heart failure, and diabetes mellitus. Which medication is the most probable cause of his hearing impairment?
Your Answer: Ramipril
Correct Answer: Bumetanide
Explanation:Bumetanide is the only medication among the options that may cause ototoxicity, marked by hearing loss. This loop diuretic is used to manage heart failure by inhibiting the Na+-K+-Cl- cotransporter in the thick ascending limb of the loop of Henle, reducing the absorption of NaCl. However, at high levels, it may also inhibit the Na+-K+-Cl- cotransporter in the inner ear, damaging the hair cells and decreasing endolymph. Amlodipine, bisoprolol, and ramipril are not known to cause ototoxicity and are used to manage hypertension and heart failure.
Loop Diuretics: Mechanism of Action and Indications
Loop diuretics, such as furosemide and bumetanide, are medications that inhibit the Na-K-Cl cotransporter (NKCC) in the thick ascending limb of the loop of Henle. This reduces the absorption of NaCl and increases the excretion of water and electrolytes, making them effective in treating conditions such as heart failure and resistant hypertension. Loop diuretics act on NKCC2, which is more prevalent in the kidneys.
As loop diuretics work on the apical membrane, they must first be filtered into the tubules by the glomerulus before they can have an effect. This means that patients with poor renal function may require higher doses to achieve a sufficient concentration within the tubules.
Loop diuretics are commonly used in the treatment of heart failure, both acutely (usually intravenously) and chronically (usually orally). They are also effective in treating resistant hypertension, particularly in patients with renal impairment.
However, loop diuretics can have adverse effects, including hypotension, hyponatremia, hypokalemia, hypomagnesemia, hypochloremic alkalosis, ototoxicity, hypocalcemia, renal impairment (from dehydration and direct toxic effect), hyperglycemia (less common than with thiazides), and gout.
In summary, loop diuretics are effective medications for treating heart failure and resistant hypertension, but their use should be carefully monitored due to potential adverse effects. Patients with poor renal function may require higher doses to achieve therapeutic effects.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 17
Incorrect
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A 25-year-old female is prescribed varenicline to aid in smoking cessation. What is the most probable adverse effect that may occur?
Your Answer: Vivid dreams
Correct Answer: Nausea
Explanation:NICE guidance recommends offering nicotine replacement therapy (NRT), varenicline, or bupropion to patients for smoking cessation, with no preference for one medication over another. NRT should be offered in combination for those with high nicotine dependence or inadequate response to single forms. Varenicline should be started a week before the target stop date and monitored for adverse effects, including nausea and suicidal behavior. Bupropion should also be started before the target stop date and is contraindicated in epilepsy, pregnancy, and breastfeeding. Pregnant women should be tested for smoking and referred to NHS Stop Smoking Services, with first-line interventions being cognitive behavior therapy, motivational interviewing, or structured self-help and support. NRT may be used if other measures fail, but varenicline and bupropion are contraindicated.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 18
Correct
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In a diabetes specialist clinic you are about to review a 62-year-old patient with type 2 diabetes mellitus, who is not responding to dietary advice and weight reduction. He therefore needs to commence taking an oral hypoglycaemic agent.
Which of the following statements is true concerning the oral hypoglycaemic agents used in the management of diabetes mellitus?Your Answer: Acarbose inhibits α-glucosidase
Explanation:Acarbose works by inhibiting the enzymes responsible for breaking down carbohydrates, specifically α-glucosidase enzymes found in the small intestine and pancreatic a-amylase. On the other hand, metformin reduces the production of glucose in the liver and increases insulin sensitivity, resulting in increased glucose uptake in peripheral tissues. Unlike sulfonylureas, metformin does not increase insulin secretion and has a lower risk of hypoglycemia. Sulfonylureas, on the other hand, increase insulin secretion by binding to ATP-sensitive K+ channels in pancreatic b-cells, but have no effect on peripheral insulin sensitivity. While the newer glitazones, rosiglitazone and pioglitazone, are not associated with hepatotoxicity, troglitazone, an older glitazone, was withdrawn due to drug-related hepatitis. Pioglitazone is associated with an increased risk of heart failure, bladder cancer, and bone fracture, and should be used with caution in high-risk individuals. Clinicians should regularly review the safety and efficacy of pioglitazone in patients to ensure that only those who benefit continue to receive treatment.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 19
Correct
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A 52-year-old woman had a anterior myocardial infarction (MI) three weeks ago and has been prescribed various drugs by the cardiology team.
Which of the following medications is most likely to decrease this patient’s mortality post-MI?
Your Answer: Bisoprolol
Explanation:Common Medications for Cardiovascular Conditions
Bisoprolol is a beta-blocker that specifically targets the heart, reducing strain by decreasing pre-load and after-load. It has been found to be effective in reducing mortality after a heart attack, especially in patients with heart failure.
Amiodarone is an anti-arrhythmic drug that can be used to prevent irregular heartbeats. However, it does not improve mortality rates in post-heart attack patients.
Isosorbide mononitrate is a medication that helps lower blood pressure and can alleviate chest pain in stable angina. It does not improve mortality rates and should be used with caution when taken with sildenafil.
Nicorandil works by dilating the coronary arteries, reducing chest pain in stable angina. While it does not improve prognostic outcomes, it can improve symptoms.
Patients who have experienced a myocardial infarction (MI) should be started on a combination of medications to improve their outcomes. The following medications are recommended for post-MI patients:
1. Statin: This medication helps to lower cholesterol levels and reduce the risk of future cardiovascular events.
2. ACE inhibitor: This medication helps to lower blood pressure and reduce the risk of heart failure.
3. Beta blocker: This medication helps to reduce the workload on the heart and improve its function.
4. Aspirin: This medication helps to prevent blood clots and reduce the risk of future cardiovascular events.
Other medications may be used to relieve symptoms, such as ISMN and nicorandil, but they do not offer any mortality benefit. It is important for post-MI patients to take their medications as prescribed and to follow up with their healthcare provider regularly to monitor their progress.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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Question 20
Incorrect
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An 72-year-old man arrives at the emergency department complaining of palpitations, dizziness, and shortness of breath. He has a medical history of COPD and is currently being treated for pneumonia with antibiotics. Upon examination, his heart rate is 170/min, respiratory rate is 22/min, blood pressure is 140/92 mmHg, and temperature is 36.3 ºC. An electrocardiogram reveals a polymorphic ventricular tachycardia with oscillatory changes in amplitude of the QRS complexes around the isoelectric line. Which medication is most likely responsible for his symptoms?
Your Answer: Doxycycline
Correct Answer: Azithromycin
Explanation:Azithromycin is the macrolide antibiotic that can cause torsades de pointes, which is evident in this patient presenting with dizziness, shortness of breath, palpitations, and polymorphic ventricular tachycardia with oscillatory changes. Macrolides can lead to a long QT interval, which can be fatal if not treated promptly with intravenous magnesium to stabilize the cardiac myocytes. Amoxicillin, doxycycline, and flucloxacillin are other antibiotics used to treat pneumonia but have not been associated with long QT intervals and torsades de pointes. However, they can cause other side effects such as diarrhea, nausea, vomiting, skin reactions, and thrombocytopenia.
Torsades de Pointes: A Life-Threatening Condition
Torsades de pointes is a type of ventricular tachycardia that is associated with a prolonged QT interval. This condition can lead to ventricular fibrillation, which can cause sudden death. There are several causes of a prolonged QT interval, including congenital conditions such as Jervell-Lange-Nielsen syndrome and Romano-Ward syndrome, as well as certain medications like antiarrhythmics, tricyclic antidepressants, and antipsychotics. Other causes include electrolyte imbalances, myocarditis, hypothermia, and subarachnoid hemorrhage.
The management of torsades de pointes involves the administration of intravenous magnesium sulfate. This can help to stabilize the heart rhythm and prevent further complications.
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This question is part of the following fields:
- Pharmacology/Therapeutics
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