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Question 1
Correct
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Regarding bupropion (Zyban), which one of the following statements is true?
Your Answer: It has an antidepressant effect
Explanation:The chief role of bupropion is that it acts as an antidepressant agent, which was used extensively to treat war veterans with post traumatic stress disorders. It is also very effective nicotine replacement therapy. Contraindications include epileptic seizures as it decreases the threshold of epilepsy in these patients to 1:1000.
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This question is part of the following fields:
- Pharmacology
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Question 2
Incorrect
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Which of the following enzymes are involved in Phase I drug metabolism?
Your Answer: Pyruvate carboxylase
Correct Answer: Alcohol dehydrogenase
Explanation:Drug metabolism can be broadly classified into:
Phase I (functionalization) reactions: also termed non-synthetic reactions, they include oxidation, reduction, hydrolysis, cyclization and de-cyclization. The most common and vital reactions are oxidation reactions. (Of the given enzymes only Alcohol dehydrogenase is involved in phase I drug metabolism. Succinate dehydrogenase, is a vital enzyme involved in the Kreb’s cycle and the mitochondrial electron transport chain). They are mainly catalysed by Cytochrome P-450 enzyme.Phase II (conjugation) reactions: occur following phase I reactions, they include reactions: glucuronidation and sulphate conjugation, etc. They are mostly catalysed by UDP-glucuronosyltransferase enzyme. Other phase II enzymes include: sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases.
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This question is part of the following fields:
- Pharmacology
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Question 3
Correct
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Which of the following types of reactions are a part of the phase II metabolism of a drug?
Your Answer: Conjugation
Explanation:Drug metabolism can be broadly classified into:
Phase I (functionalization) reactions: also termed non-synthetic reactions, they include oxidation, reduction, hydrolysis, cyclization and de-cyclization. The most common and vital reactions are oxidation reactions. (Of the given enzymes only Alcohol dehydrogenase is involved in phase I drug metabolism. Succinate dehydrogenase, is a vital enzyme involved in the Kreb’s cycle and the mitochondrial electron transport chain). They are mainly catalysed by Cytochrome P-450 enzyme.Phase II (conjugation) reactions: occur following phase I reactions, they include reactions: glucuronidation and sulphate conjugation, etc. They are mostly catalysed by UDP-glucuronosyltransferase enzyme. Other phase II enzymes include: sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases.
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This question is part of the following fields:
- Pharmacology
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Question 4
Correct
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Which of the following drugs does not cause broncho-dilatation?
Your Answer: Atenolol
Explanation:Atenolol is a beta-selective (cardio selective) adrenoceptor blocking drug without partial agonist or membrane stabilising activity. Higher doses of Atenolol causes broncho-constriction.
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This question is part of the following fields:
- Pharmacology
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Question 5
Correct
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Organophosphates, such as Sarin, have been used as chemical-warfare agents by terrorists.
Which of the following statements is true concerning organophosphate poisoning?Your Answer: Atropine is useful in the management of organophosphate poisoning
Explanation:The principal action of organophosphates is the inhibition of acetylcholinesterase’s, therefore leading to the accumulation of acetylcholine at muscarinic receptors (miosis, hypersalivation, sweating, diarrhoea, excessive bronchial secretions), nicotinic receptors (muscle fasciculations and tremor) and in the central nervous system (anxiety, loss of memory, headache, coma).
Removal from the source of the organophosphate, adequate decontamination, supplemental oxygen and atropine are the initial treatment measures. Pralidoxime, an activator of cholinesterase, should be given to all symptomatic patients.
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This question is part of the following fields:
- Pharmacology
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Question 6
Correct
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A 45-year-old male complained of deteriorating vision after starting a new drug. Which of following could NOT be responsible for this presentation?
Your Answer: Irinotecan
Explanation:Chloroquine causes Bull’s eye maculopathy which consists of a number of different conditions in which there is a ring of pale-looking damage around a darker area of the macula.
Ethambutol causes optic neuritis.
Quinine causes blurred vision and changes in colour vision.
Vincristine causes optic nerve atrophy as a result of chronic optic nerve oedema or optic neuritis.
Irinotecan does not have any ocular side effects. -
This question is part of the following fields:
- Pharmacology
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Question 7
Correct
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Tranexamic acid is used to treat heavy menstrual bleeding in women. It inhibits menorrhagia by which of the following mechanisms?
Your Answer: Inhibits fibrinolysis
Explanation:Tranexamic acid prevents menorrhagia by inhibiting fibrinolysis thus promoting coagulation.
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This question is part of the following fields:
- Pharmacology
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Question 8
Incorrect
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A 56-year-old male presents to the emergency department with confusion and agitation for the past four hours. He is a known alcoholic who has abstained from drinking for the past three days.
On examination, he is sweating, agitated and disoriented. His temperature is 37.7°C, pulse 112 bpm regular and blood pressure is 150/76 mmHg.
Blood investigations performed in the emergency department reveal:
FBC: Normal
U&E: Normal
Plasma glucose: 4.6 mmol/l (3.6-6)
Which of the following medications would be the most appropriate treatment for this man?Your Answer: Oral diazepam
Correct Answer: Oral lorazepam
Explanation:The most probable diagnosis for this patient is delirium tremens due to alcohol withdrawal, which should be treated as a medical emergency.Â
Delirium tremens is a hyperadrenergic state and is often associated with tachycardia, hyperthermia, hypertension, tachypnoea, tremor, and mydriasis.
Treatment:
– The most common and validated treatment for alcohol withdrawal is benzodiazepine: first-line treatment includes oral lorazepam.
– If the symptoms persist, or the medication is refused, parenteral lorazepam, haloperidol or olanzapine should be given.
– Central-acting, alpha-2 agonists such as clonidine and dexmedetomidine should not be used alone for the treatment of alcohol withdrawal.
– It is also recommended to avoid using alcohol, antipsychotics, anticonvulsants, beta-adrenergic receptor blockers, and baclofen for the treatment of alcohol withdrawal as there are not enough studies to support the safety of these. -
This question is part of the following fields:
- Pharmacology
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Question 9
Correct
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The following drugs are given for different types of respiratory conditions. Which of the following drugs exerts its action by inhibiting phosphodiesterase?
Your Answer: Theophylline
Explanation:Theophylline relaxes the smooth muscles of the respiratory tract and suppresses the response of the airways to stimuli by increasing tissue concentration of cyclic adenine monophosphate (cAMP) by inhibiting phosphodiesterase. Dobutamine has strong beta1 and weak beta2/alpha effects, resulting in increased cardiac output, blood pressure, and heart rate, as well as decreased peripheral vascular resistance. Doxapram produces respiratory stimulation in medulla through peripheral carotid chemoreceptors. Ipratropium inhibits vagally mediated reflexes by antagonizing acetylcholine action which prevents increase in intracellular calcium concentration and ultimately causes bronchial smooth muscle relaxation. Salbutamol is a short-acting β2 adrenergic receptor agonist which causes smooth muscle relaxation.
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This question is part of the following fields:
- Pharmacology
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Question 10
Incorrect
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A patient has been taking morphine 60 mg twice a day and sevredol (quick release morphine) 20 mg three times a day, per os. You are asked to prescribe morphine subcutaneously for this palliative care patient via a syringe driver. Which of the following dosing regimen would you choose?
Your Answer: 180 mg over 24 hours. 60 mg as required, for breakthrough pain.
Correct Answer: 90 mg over 24 hours. 15 mg as required, for breakthrough pain.
Explanation:Morphine is almost twice as effective when given intravenously or subcutaneously as when given orally. This means that the first step is to calculate the total amount of morphine that the patient used to take orally, which is 180 mg. Since the patient needed 180 mg of morphine tablets in 24 hours to control his pain, he now would need approximately 90 mg given in the same time span. In order to calculate the breakthrough dose, one sixth of the total dose of morphine required per 24 hours should be calculated. The patient now requires 90 mg of morphine subcutaneously, meaning that he would need 15 mg for breakthrough pain.
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This question is part of the following fields:
- Pharmacology
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Question 11
Incorrect
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A 60-year-old man suffers from depression, poor concentration and inability to sleep. A few months earlier, he had a few episodes of debauchery and tantrums. Which drug is most likely to benefit him?
Your Answer: Haloperidol
Correct Answer: Carbamazepine
Explanation:Carbamazepine would be the drug of choice in this case because it is an anti-convulsant. It helps to restore the normal levels of nerve activity in the brain.
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This question is part of the following fields:
- Pharmacology
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Question 12
Correct
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A 60-year-old male was diagnosed with advanced intestinal carcinoma with metastasis. His doctor prescribed him NSAIDs and tramadol initially but his pain was not responding to it. Which of the following drugs is the most suitable alternative option?
Your Answer: Oramorph
Explanation:According to WHO, initial pain management for patients with malignancy involves NSAIDs and weak opioids. After their pain stops responding to them, stronger opioids such as oxycodone and morphine are prescribed.
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This question is part of the following fields:
- Pharmacology
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Question 13
Correct
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A 50-year-old Afro-Caribbean male is noted to have a blood pressure of 186/99 mmHg. He also suffers from asthma. Which of the following anti-hypertensive drugs will be ineffective in this specific patient?
Your Answer: ACE inhibitor
Explanation:The Afro-Caribbean population is found to have an increased sensitivity of blood pressure to salt intake as well as a reduced tendency to excrete the ingested salt, associated with low renin levels. ACE inhibitors will then be an ineffective group of anti-hypertensive drugs for this specific population.
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This question is part of the following fields:
- Pharmacology
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Question 14
Incorrect
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Which among the following antihypertensives is centrally acting?
Your Answer: Hydralazine
Correct Answer: Moxonidine
Explanation:Moxonidine and alpha-methyl dopa are centrally acting antihypertensives and modify blood pressure through modifying sympathetic activity.
Other options:
Verapamil is a calcium antagonist.
Minoxidil and hydralazine are both vasodilators.
Phenoxybenzamine is an alpha-blocker.Adverse effects:
Dry mouth and somnolence were the most frequently reported adverse events, followed by headache, dizziness, nausea and allergic skin reactions. -
This question is part of the following fields:
- Pharmacology
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Question 15
Incorrect
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A 42-year-old female with a history of hypertension presented with increased thirst, polyuria and nocturia for 2 weeks duration. Her random blood sugar was 12 mmol/l. Which of the following antihypertensives can cause the above clinical presentation?
Your Answer:
Correct Answer: Bendroflumethiazide
Explanation:Thiazides and beta-blockers have been most commonly linked to the development of diabetes mellitus.
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This question is part of the following fields:
- Pharmacology
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Question 16
Incorrect
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A woman presents having overdosed on Imipramine. Which investigation should be done immediately?
Your Answer:
Correct Answer: ECG
Explanation:Imipramine is a NSRI tricyclic antidepressant. It has a narrow therapeutic index . It might cause tachyarrhythmia and ECG changes.
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This question is part of the following fields:
- Pharmacology
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Question 17
Incorrect
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The mechanism of action of low molecular weight heparin, has the greatest effect on which of the following components of the coagulation cascade?
Your Answer:
Correct Answer: Factor Xa
Explanation:Mechanism of action of low molecular weight heparin (LMWH):
It inhibits coagulation by activating antithrombin III. Antithrombin III binds to and inhibits factor Xa. In doing so it prevents activation of the final common path; Xa inactivation means that prothrombin is not activated to thrombin, thereby not converting fibrinogen into fibrin for the formation of a clot.LMHW is a small fragment of a larger mucopolysaccharide, heparin. Heparin works similarly, by binding antithrombin III and activating it. Heparin also has a binding site for thrombin, so thrombin can interact with antithrombin III and heparin, thus inhibiting coagulation.
Heparin has a faster onset of anticoagulant action as it will inhibit not only Xa but also thrombin, while LMWH acts only on Xa inhibition.Compared to heparin, LMWHs have a longer half-life, so dosing is more predictable and can be less frequent, most commonly once per day.
Dosage and uses:
LMWH is administered via subcutaneous injection. This has long-term implications on the choice of anticoagulant for prophylaxis, for example, in orthopaedic patients recovering from joint replacement surgery, or in the treatment of DVT/PE.Adverse effects:
The main risk of LMWH will be bleeding. The specific antidote for heparin-induced bleeding is protamine sulphate.
Less commonly it can cause:
Heparin-induced thrombocytopenia (HIT)
Osteoporosis and spontaneous fractures
Hypoaldosteronism
Hypersensitivity reactions -
This question is part of the following fields:
- Pharmacology
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Question 18
Incorrect
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What is the mechanism of action of sumatriptan?
Your Answer:
Correct Answer: 5-HT1 agonist
Explanation:Triptans are specific 5-HT1 agonists used in the acute treatment of migraine. They are generally used as first-line therapy in combination with an NSAID or paracetamol.
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This question is part of the following fields:
- Pharmacology
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Question 19
Incorrect
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All of the following drugs reduce the tone of the lower oesophageal sphincter except?
Your Answer:
Correct Answer: Domperidone
Explanation:Domperidone is a D2 dopaminergic receptor antagonist which works as an anti emetic by increasing the tone of the lower oesophageal sphincter and increasing the gut motility.
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This question is part of the following fields:
- Pharmacology
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Question 20
Incorrect
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A 35-year-old female with chronic pelvic pain, was recently diagnosed with PID. She was prescribed doxycycline. After 2 days she returned with complaints of abdominal bloating, nausea and regurgitation. Which of the following advice should be given to her?
Your Answer:
Correct Answer: Take Doxycycline after meals
Explanation:Doxycycline is known to cause dyspeptic symptoms. So advising to take Doxycycline after meals is important. Taking with meals or adding an antacid is not advised, as both will cause reduction in drug absorption.
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This question is part of the following fields:
- Pharmacology
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Question 21
Incorrect
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A 60-year-old male complained of pain and redness at the metatarsophalangeal joints of left big toe. He was on treatment for hypertension. Which of the following antihypertensive drugs is responsible for the above symptom?
Your Answer:
Correct Answer: Bendroflumethiazide
Explanation:The clinical diagnosis is acute gout. According to the latest research diuretics, β blockers, angiotensin converting enzyme inhibitors, and non-losartan angiotensin II receptor blockers are associated with an increased risk of gout, as those drugs increase serum uric acid levels. Calcium channel blockers and losartan are associated with a lower risk. Thiazide diuretics have the highest association with gout.
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This question is part of the following fields:
- Pharmacology
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Question 22
Incorrect
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A 60-year-old male is under treatment with azathioprine after a renal transplant. During his review, he complains of pain and swelling over his left great toe. Investigations reveal hyperuricemia. Suspecting gout, he was started on allopurinol. Subsequently, he develops aplastic anaemia. Which of the following is the most appropriate reason for his bone marrow failure?
Your Answer:
Correct Answer: Mercaptopurine toxicity
Explanation:The cause for bone marrow suppression in this patient is most probably mercaptopurine toxicity.
Azathioprine is metabolized to 6-mercaptopurine (6-MP), which itself is metabolized by xanthine oxidase.
Xanthine oxidase inhibition by allopurinol leads to the accumulation of 6-MP which then precipitates bone marrow failure.
This may be potentially fatal if unrecognized.
Clinical presentation:
Toxicity symptoms include gastrointestinal symptoms, bradycardia, hepatotoxicity, myelosuppression. -
This question is part of the following fields:
- Pharmacology
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Question 23
Incorrect
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A 65-year-old man presents to you three weeks after initiating metformin for type 2 diabetes mellitus. His body mass index is 27.5 kg/m^2. At a dose of 500mg TDS the patient has experienced significant diarrhoea. Even on reducing the dose to 500mg BD his symptoms persisted. What is the most appropriate next step in this patient?
Your Answer:
Correct Answer: Start modified release metformin 500mg od with evening meal
Explanation:Here, the patient seems to be intolerant to standard metformin. In such cases, modified-release preparations is considered as the most appropriate next step.
There is some evidence that these produce fewer gastrointestinal side-effects in patients intolerant of standard-release metformin.Metformin is a biguanide and reduces blood glucose levels by decreasing the production of glucose in the liver, decreasing intestinal absorption and increasing insulin sensitivity.
Metformin decreases both the basal and postprandial blood glucose.
Other uses: In Polycystic Ovarian Syndrome (PCOS), Metformin decreases insulin levels, which then decreases luteinizing hormone and androgen levels. Thus acting to normalize the menstruation cycle.Note:
Metformin is contraindicated in patients with severe renal dysfunction, which is defined as a glomerular filtration rate (GFR) less than 30 ml/min/1.732m2.
Metformin overdose has been associated with hypoglycaemia and lactic acidosis, for this reason, it has a black box warning for lactic acidosis. -
This question is part of the following fields:
- Pharmacology
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Question 24
Incorrect
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Which of the following vaccinations is contraindicated in patients with malignancy undergoing chemotherapy?
Your Answer:
Correct Answer: Rubella
Explanation:MMR vaccine is a live vaccine. It contains measles, mumps and rubella. These vaccines should be avoided during chemotherapy and for 6 months after.
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This question is part of the following fields:
- Pharmacology
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Question 25
Incorrect
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Which of the given adverse effects should be anticipated following the administration of an anticholinesterase?
Your Answer:
Correct Answer: Bradycardia and miosis
Explanation:Bradycardia and miosis should be anticipated following the administration of anticholinesterases.
Anticholinesterase agents include the following medications:
– Pyridostigmine, neostigmine, and edrophonium which play a significant role in the diagnosis and the management of myasthenia gravis.
– Rivastigmine, galantamine and donepezil are cholinesterase inhibitors found to be significantly useful in the management of Alzheimer’s disease.Mechanism of action and pharmacological effects:
Inhibition of cholinesterase increases the level and the duration of action of acetylcholine within the synaptic cleft.Thus, cholinergic effects such as a reduction in heart rate (bradycardia), miosis (pupillary constriction), increased secretions, increased gastrointestinal motility and reduction in BP may occur with anticholinesterases.
Toxins such as organophosphates and carbamates also are primarily anticholinergic and cause the following typical SLUDGE symptoms:
– Salivation
– Lacrimation
– Urination
– Diaphoresis
– Gastrointestinal upset
– Emesis -
This question is part of the following fields:
- Pharmacology
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Question 26
Incorrect
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What is the mechanism of action of carbimazole?
Your Answer:
Correct Answer: Inhibition of the iodination of tyrosine
Explanation:Carbimazole is used to treat hyperthyroidism. Carbimazole is a pro-drug as after absorption it is converted to the active form, methimazole. Methimazole prevents thyroid peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglobulin, hence reducing the production of the thyroid hormones T3 and T4 (thyroxine).
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This question is part of the following fields:
- Pharmacology
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Question 27
Incorrect
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A 50-year-old male patient with Pulmonary Tuberculosis is taking Ethambutol, Isoniazid, Pyrazinamide, Pyridoxine, and Rifampicin. Which of the above drugs is associated with peripheral neuropathy?
Your Answer:
Correct Answer: Isoniazid
Explanation:Isoniazid is associated with peripheral neuropathy, which occurs due to deficiency of biologically active pyridoxine. The deficiency is caused by the combination of isoniazid and pyridoxine to form a hydrazone which is excreted in the urine. Pyridoxine supplementation reduces the risk associated with Isoniazid.
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This question is part of the following fields:
- Pharmacology
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Question 28
Incorrect
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Question 29
Incorrect
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A 39-year-old accountant with long-standing gastro-oesophageal reflux disease is reviewed in clinic. He has recently switched from ranitidine to omeprazole.
What is the main benefit of omeprazole compared to ranitidine?Your Answer:
Correct Answer: Irreversible blockade of H+/K+ ATPase
Explanation:Proton pump inhibitors can reduce gastric acid secretion by up to 99%. Acid production resumes following the normal renewal of gastric parietal cells.
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This question is part of the following fields:
- Pharmacology
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Question 30
Incorrect
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What is the rationale concerning the use of sodium cromoglycate in the prophylaxis of bronchial asthma?
Your Answer:
Correct Answer: Inhibition of mast-cell degranulation
Explanation:Sodium cromoglycate principally acts by inhibiting the degranulation of mast cells triggered by the interaction of antigen and IgE.
The inhibitory effect on mast cells appears to be cell-type specific since cromoglycate has little inhibitory effect on mediator release from human basophils.
Thus, it inhibits the release of histamine, leukotrienes, and slow-reacting substance of anaphylaxis from mast cells by inhibiting degranulation following exposure to reactive antigens.Adverse effects include cough, flushing, palpitation, chest pain, nasal congestion, nausea, fatigue, migraine, etc.
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This question is part of the following fields:
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
