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Question 1
Correct
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A 28-year-old female admitted for a course of chemotherapy, has been taking high dose steroids for a few days. The nurses report that she is very agitated and talks about trying to open the window of her room and jump out from the fourth floor. You review her notes and see that she admits to drinking a few glasses of wine per week and has smoked cannabis on a few occasions. On examination her BP is 145/88 mmHg, her pulse is 80 bpm. Blood investigations reveal: Haemoglobin: 12.1 g/dL (11.5-16.5) WBC count: 16.2 x 103/dL (4-11) Platelets: 200 x 109/L (150-400) C-reactive protein: 9 nmol/l (<10) Sodium: 140 mmol/l (135-146) Potassium: 3.9 mmol/l (3.5-5) Creatinine: 92 μmol/l (79-118) Which of the following is the most likely diagnosis?
Your Answer: Corticosteroid-related psychosis
Explanation:Agitation, hypomania and suicidal intent within a few days after initiating corticosteroid therapy is highly suggestive of a diagnosis of corticosteroid-induced psychosis.
In some patients corticosteroid related psychosis has been diagnosed up to 12 weeks or more after commencing therapy.
Euphoria and hypomania are considered to be the most common psychiatric symptoms reported during short courses of steroids.
During long-term treatment, depressive symptoms were the most common.
Higher steroid doses appear to carry an increased risk for such adverse effects; however, there is no significant relationship between dose and time to onset, duration, and severity of symptoms.Management: Reduction or cessation of corticosteroids is the mainstay of treatment for steroid psychosis. For those patients who cannot tolerate this reduction/cessation of steroids, mood stabilizers may be of some benefit.
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This question is part of the following fields:
- Pharmacology
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Question 2
Correct
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A 47-year-old male with type II diabetes mellitus presents to your clinic with a history suggestive of erectile dysfunction. You decide to start him on sildenafil citrate. What is the mechanism of action of this drug?
Your Answer: Phosphodiesterase type V inhibitor
Explanation:Sildenafil (Viagra) is a phosphodiesterase type V inhibitor used in the treatment of impotence.
Contraindications:
– Patients taking nitrates and related drugs such as nicorandil
– Hypotension
– Recent stroke or myocardial infarction (NICE recommend waiting 6 months)Side-effects:
Visual disturbances e.g. cyanopsia, non-arthritic anterior ischaemic Neuropathy
Nasal congestion
Flushing
Gastrointestinal side-effects
Headache -
This question is part of the following fields:
- Pharmacology
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Question 3
Correct
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A 20-year-old male presents to the emergency department about 4 hours after ingesting 20g of paracetamol. N-acetyl cysteine was started immediately. What is the mechanism of action of N-acetyl cysteine?
Your Answer: Replenishes glutathione
Explanation:N-acetylcysteine depletes glutathione reserves by providing cysteine, which is an essential precursor in glutathione production.
Glutathione within the liver can normally detoxify these minuscule quantities of NAPQI and prevent tissue damage.
N-acetylcysteine (NAC) is the mainstay of therapy for acetaminophen toxicity.Paracetamol overdose:
The liver normally conjugates paracetamol with glucuronic acid/sulphate. During an overdose, the conjugation system becomes saturated leading to oxidation by cytochrome P450 (predominately CYP2E1) mixed-function oxidases. This produces a toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI).Normally glutathione acts as a defence mechanism by conjugating with the toxin forming the non-toxic mercapturic acid. If glutathione stores run-out, the toxin forms covalent bonds with cell proteins, denaturing them and leading to cell death.
Other uses: In COPD, cystic fibrosis, and other lung conditions, nebulized NAC has mucolytic, anti-inflammatory, and antioxidant properties.
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This question is part of the following fields:
- Pharmacology
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Question 4
Incorrect
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A 74-year-old man who has been diagnosed with atrial fibrillation and heart failure is being started on digoxin. What is the mechanism of action of digoxin?
Your Answer: inhibits the Na+/K+ ATPase pump
Correct Answer:
Explanation:Digoxin acts by inhibiting the Na+/K+ ATPase pump.
Digoxin is a cardiac glycoside now mainly used for rate control in the management of atrial fibrillation. As it has positive inotropic properties it is sometimes used for improving symptoms (but not mortality) in patients with heart failure.Mechanism of action:
It decreases the conduction through the atrioventricular node which slows the ventricular rate in atrial fibrillation and atrial flutter.
It increases the force of cardiac muscle contraction due to inhibition of the Na+/K+ ATPase pump. It also stimulates the vagus nerve.Digoxin toxicity:
Plasma concentration alone does not determine whether a patient has developed digoxin toxicity. The likelihood of toxicity increases progressively from 1.5 to 3 mcg/l.
Clinical feature of digoxin toxicity include a general feeling of unwell, lethargy, nausea & vomiting, anorexia, confusion, xanthopsia, arrhythmias (e.g. AV block, bradycardia), and gynaecomastiaPrecipitating factors:
Hypokalaemia
Increasing age
Renal failure
Myocardial ischemia
Hypomagnesaemia, hypercalcemia, hypernatremia, acidosis
Hypoalbuminemia
Hypothermia
Hypothyroidism
Drugs: amiodarone, quinidine, verapamil, diltiazem, spironolactone (competes for secretion in the distal convoluted tubule, therefore, reduce excretion), ciclosporin. Also, drugs that cause hypokalaemia e.g. thiazides and loop diuretics.Management of digoxin toxicity:
Digibind
Correct arrhythmias
Monitor and maintain potassium levels within the normal limits. -
This question is part of the following fields:
- Pharmacology
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Question 5
Correct
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What is the mechanism of action of sumatriptan?
Your 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 6
Correct
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A 45-year-old male is brought to the emergency department after being found collapsed, outside a nightclub. The ER team found an empty bottle of amyl nitrate in his pocket. The patient is hypoxic with an O2 saturation of 84% and is confused. Which of the following is the best treatment for this patient?
Your Answer: Methylene blue
Explanation:The best treatment for the patient in question would be methylene blue.
The most probable diagnosis in this patient is methemoglobinemia due to the ingestion of amyl nitrate.Amyl nitrate promotes the formation of methaemoglobin, which avidly conserves oxygen and leads to decreased tissue oxygen saturations.
Treatment of choice includes methylene blue and vitamin C.
Adverse effects:
Benign side effects include green or blue discoloration of urine and patients should be forewarned.
Significant side effects are based on methylene blue, itself, being an oxidizing agent and an inhibitor of monoamine oxidase A (MAO-A).
As an oxidizing agent, methylene blue can actually precipitate methemoglobinemia or haemolysis in high doses or when ineffectively reduced.
Methylene blue administration in a patient taking a serotonergic agents may predispose to serotonin syndrome.Note: Although methylene blue administration is controversial in the setting of G6PD-deficiency due to reduced levels of NADPH, it is not contraindicated and should be administered cautiously and judiciously.
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This question is part of the following fields:
- Pharmacology
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Question 7
Correct
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A 50-year-old patient was started on ezetimibe, for his cholesterol a few days back. Which among the following statements is true regarding ezetimibe?
Your Answer: Its principal action is to reduce intestinal cholesterol absorption
Explanation:Ezetimibe is a cholesterol-lowering agent that acts to prevent cholesterol absorption by directly inhibiting cholesterol receptors on enterocytes.
It does not affect the absorption of drugs (e.g. digoxin, thyroxine) or fat-soluble vitamins (A, D and K) as the anion-exchange resins do. It does not affect the cytochrome P450 enzyme system.
The increased risk of myositis associated with the statins is not seen with ezetimibe.
The most common adverse effects include headache, runny nose, and sore throat.
Less common reactions include body aches, back pain, chest pain, diarrhoea, joint pain, fatigue, and weakness. -
This question is part of the following fields:
- Pharmacology
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Question 8
Incorrect
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A 55-year-old male presents with complaints suggestive of erectile dysfunction. He also provides a history of ischaemic heart disease for which he is under treatment. The GP decides to start him on sildenafil citrate. Which of the following medications may contraindicate the use of sildenafil in this patient?
Your Answer: Losartan
Correct Answer: Nicorandil
Explanation:The use of nitrates and nicorandil concomitantly with sildenafil citrate is contraindicated.
Sildenafil (Viagra) is a phosphodiesterase type V inhibitor used in the treatment of impotence.
Contraindications
– Patients taking nitrates and related drugs such as nicorandil
– Hypotension
– Recent stroke or myocardial infarction (NICE recommend waiting 6 months)Side-effects:
Visual disturbances e.g. cyanopsia, non-arthritic anterior ischaemic Neuropathy
Nasal congestion
Flushing
Gastrointestinal side-effects
Headache -
This question is part of the following fields:
- Pharmacology
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Question 9
Correct
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An 80-year-old woman with advanced COPD has been admitted to the medicine ward in an unconscious state. She appears to have an acute lower respiratory tract infection. After consulting with an anaesthesiologist it was concluded that she was not a candidate for intensive care unit admission and thus, a decision was made to start the patient on doxapram therapy. Which of the following best fits the characteristics of doxapram?
Your Answer: It is contraindicated in hyperthyroidism
Explanation:The two statements that fit the characteristics of doxapram are, epilepsy is a contraindication for doxapram use and concurrent use with theophylline may increase agitation.
Doxapram is a central respiratory stimulant. In clinical practice, doxapram is usually used for patients who have an acute exacerbation of chronic obstructive pulmonary disease (COPD) who are unsuitable for admission to the intensive therapy unit for ventilatory support. Doxapram infusion may buy an extra 24 h to allow for recovery.
Contraindications include: ischaemic heart disease, epilepsy, cerebral oedema, acute stroke, asthma, hypertension, hyperthyroidism, and pheochromocytoma.
The infusion may worsen agitation and dyspnoea and lead to hypertension, nausea, vomiting and urinary retention.Drug interactions:
Concomitant administration of doxapram and aminophylline (theophylline) can cause increased skeletal muscle activity, agitation, and hyperactivity. -
This question is part of the following fields:
- Pharmacology
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Question 10
Correct
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A 25-year-old male presents to the emergency department with fever, sweating, hyperventilation and breathing difficulty. He also complains of a continuous ringing sensation in both his ears for the past couple of days. He admits to consuming a lot of over the counter painkillers for the past few days. Which of the following drugs is the most likely cause of these symptoms?
Your Answer: Aspirin
Explanation:The presence of tinnitus, fever and hyperventilation are clues for aspirin (salicylate) toxicity.
Clinical Presentation of salicylate toxicity can include:
• Pulmonary manifestations include: Hyperventilation, hyperpnea, severe dyspnoea due to noncardiogenic pulmonary oedema, fever and dyspnoea due to aspiration pneumonitis
• Auditory symptoms caused by the ototoxicity of salicylate poisoning include: Hard of hearing and deafness, and tinnitus (commonly encountered when serum salicylate concentrations exceed 30 mg/dL).
• Cardiovascular manifestations include: Tachycardia, hypotension, dysrhythmias – E.g., ventricular tachycardia, ventricular fibrillation, multiple premature ventricular contractions, asystole – with severe intoxication, Electrocardiogram (ECG) abnormalities – E.g., U waves, flattened T waves, QT prolongation may reflect hypokalaemia.
• Neurologic manifestations include: CNS depression, with manifestations ranging from somnolence and lethargy to seizures and coma, tremors, blurring of vision, seizures, cerebral oedema – With severe intoxication, encephalopathy
• GI manifestations include: Nausea and vomiting, which are very common with acute toxicity, epigastric pain, GI haemorrhage – More common with chronic intoxication, intestinal perforation, pancreatitis, hepatitis – Generally in chronic toxicity; rare in acute toxicity, Oesophageal strictures – Reported as a very rare delayed complication
• Genitourinary manifestations include: Acute kidney injury (NSAID induced Nephropathy) is an uncommon complication of salicylate toxicity, renal failure may be secondary to multisystem organ failure.
• Hematologic effects may include prolongation of the prothrombin and bleeding times and decreased platelet adhesiveness. Disseminated intravascular coagulation (DIC) may be noted with multisystem organ failure in association with chronic salicylate toxicity.
• Electrolyte imbalances like: Dehydration, hypocalcaemia, acidaemia, Syndrome of inappropriate antidiuretic hormone secretion (SIADH), hypokalaemia
Management of these patients should be done in the following manner:
• Secure Airway, Breathing, and Circulation
• Supportive therapy
• GI decontamination
• Urinary excretion and alkalization
• Haemodialysis -
This question is part of the following fields:
- Pharmacology
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Question 11
Correct
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A 30-year-old female presents with a 4-day history of diarrhoea and vomiting. She has been unable to keep fluids down for 4 days and has been treated with metoclopramide. She develops a dystonic reaction. What is the most appropriate treatment for the woman?
Your Answer: Benztropine
Explanation:Acute dystonic reactions (extrapyramidal symptoms) such as spasmodic torticollis, trismus, and oculogyric crises can occur following the administration of metoclopramide or stemetil and thus, neither is recommended for the treatment of nausea in young women.
Such reactions respond well to treatment with benztropine or procyclidine.
– Benztropine: It is an anticholinergic medication with significant CNS penetration.
A single dose of benztropine 1 to 2 mg IV followed by 1 to 2 mg p.o twice a day for up to 7 days to prevent a recurrence. Subsequently, both the offending agent and those from the same group should be avoided.
– Alternatively, diphenhydramine can be used intravenously (up to a dose of 50mg) or intramuscularly followed by p.o therapy every 6 hours for 1 to 2 to prevent a recurrence.
– Second-line therapy with IV benzodiazepines is reserved for those patients who do not respond to anticholinergics. -
This question is part of the following fields:
- Pharmacology
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Question 12
Incorrect
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A 50-year-old hypertensive male on phenytoin and clobazam for partial seizures is also taking lisinopril, cimetidine, sucralfate, and allopurinol. The last few drugs were added recently. He now presents with ataxia, slurred speech, and blurred vision. Which recently added drug is most likely to be the cause of his latest symptoms?
Your Answer: Lisinopril
Correct Answer: Cimetidine
Explanation:The symptoms of ataxia, slurred speech and blurred vision are all suggestive of phenytoin toxicity. Cimetidine increases the efficacy of phenytoin by reducing its hepatic metabolism.
Phenytoin has a narrow therapeutic index (10-20 mg/L) and its levels are monitored by measuring the total phenytoin concentration.
Cimetidine is an H2 receptor antagonist used in the treatment of peptic ulcers. It acts by decreasing gastric acid secretion.
Cimetidine also has an inhibitory effect on several isoforms of the cytochrome enzyme system including the CYP450 enzymatic pathway. Phenytoin is metabolized by the same cytochrome P450 enzyme system in the liver.
Thus, the simultaneous administration of both these medications leads to an inhibition of phenytoin metabolism and thus increases its circulating levels leading to phenytoin toxicity. -
This question is part of the following fields:
- Pharmacology
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Question 13
Correct
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A 22-year-old female comes to you for counselling regarding the initiation of combined oral contraceptive pill. Which of the following statements is correct?
Your Answer: She will still be protected against pregnancy if she takes amoxicillin for a lower respiratory tract infection while on the combined pill
Explanation:The true statement among the given options is that she will still be protected against pregnancy if she takes amoxicillin for a lower respiratory tract infection while on the combined pill.
Other than enzyme-inducing antibiotics such as rifampicin, antibiotics do not reduce the efficacy of the combined oral contraceptive pill.
It was previously advised that barrier methods of contraception should be used if taking an antibiotic while using the contraceptive pill, due to concerns that antibiotics might reduce the absorption of the pill. This is now known to be untrue. However, if the absorptive ability of the gut is compromised for another reason, such as severe diarrhoea or vomiting, or bowel disease, this may affect the efficacy of the pill.
The exception to the antibiotic rule is that hepatic enzyme-inducing antibiotics such as rifampicin and rifaximin do reduce the efficacy of the pill. Other enzyme-inducing drugs, such as phenytoin, phenobarbital, carbamazepine or St John’s Wort can also reduce the effectiveness of the pill.
Other options:
The combined pill is often prescribed for women with heavy periods as it can make them lighter and less painful.
There is no evidence that women on the combined pill put on any significant weight, although they may experience bloating at certain times in the course.
Women on the pill require monitoring of their blood pressure.
There are multiple different types of combined pills. -
This question is part of the following fields:
- Pharmacology
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Question 14
Correct
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Which of the following statements is false regarding the bioavailability of a drug?
Your Answer: The bioavailability of a drug given orally is often affected by the degree of renal elimination
Explanation:Renal elimination of a drug has no role in altering the bioavailability of a drug.
The bioavailability of a drug is the proportion of the drug which reaches systemic circulation.
Mathematically, bioavailability is the AUCoral/AUCiv x 100%, where AUC = area under the concentration-time curve following a single (oral or iv) dose.Other options are true:
By definition, the bioavailability of a drug given intravenously is 100%.
Drugs given orally that undergo high pre-systemic (first-pass) metabolism in the liver or gut wall have a low bioavailability e.g. lidocaine.
Bioavailability is also affected by the degree of absorption from the gut and this can change depending on gut motility and administration of other drugs. -
This question is part of the following fields:
- Pharmacology
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Question 15
Correct
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A 27-year-old female diagnosed with rheumatoid arthritis has failed to respond to methotrexate and sulfasalazine. Her GP decides to start her on etanercept injections. Which one among the following is an adverse effect associated with the use of etanercept?
Your Answer: Reactivation of tuberculosis
Explanation:Among the give options, reactivation of tuberculosis may occur in a patient under treatment with etanercept.
Etanercept is a biological TNF inhibit commonly used to control ankylosing spondylitis, juvenile idiopathic arthritis, plaque psoriasis, psoriatic arthritis, and rheumatoid arthritis.
Etanercept is a soluble receptor that binds both TNF-alpha and TNF-beta to inhibit the inflammatory response in joints and skin that is characteristic of these autoimmune disorders.
The most common adverse effects include infections (viral, bacterial, and fungal – mostly upper respiratory tract infections) and injection site reaction (erythema, itching, pain, swelling, bleeding, bruising).
Rarely it can also cause, reactivation of hepatitis B and TB, pneumocystis pneumonia, congestive cardiac failure, Steven-Johnson syndrome, toxic epidermal necrolysis, etc. -
This question is part of the following fields:
- Pharmacology
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Question 16
Correct
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What is the mechanism of action of carbimazole?
Your 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 17
Incorrect
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A 30-year-old male is brought to the emergency department following his collapse in a night club. His friends who accompanied him admit that, of recent, he has been using increasing amounts of cocaine. Which among the following is commonly associated with cocaine overdose?
Your Answer: Hypothermia
Correct Answer: Metabolic acidosis
Explanation:Metabolic acidosis is associated with cocaine overdose.
In overdose, cocaine leads to agitation, tachycardia, hypertension, sweating, hallucinations, and finally convulsions.
Metabolic acidosis, hyperthermia, rhabdomyolysis, and ventricular arrhythmias also occur.
Chronic use may be associated with premature coronary artery disease, dilated cardiomyopathy, and increased risk of cerebral haemorrhage.
There are 3 stages for acute cocaine toxicity:
Stage I: CNS symptoms of headache, vertigo, pseudo hallucinations, hyperthermia, hypertension.
Stage II: increased deep tendon reflexes, tachypnoea, irregular breathing, hypertension.
Stage III: Areflexia, coma, fixed and dilated pupils, hypotension, ventricular fibrillation, apnoea, and respiratory failure.Treatment:
– Airway, breathing, and circulation to be secured. The patient’s fever should be managed, and one should rule out hypoglycaemia as a cause of the neuropsychiatric symptoms.
– Cardiovascular toxicity and agitation are best-treated first-line with benzodiazepines to decrease CNS sympathetic outflow.
– The mixed beta/alpha blocker labetalol is safe and effective for treating concomitant cocaine-induced hypertension and tachycardia.
– Non-dihydropyridine calcium channels blockers such as diltiazem and verapamil have been shown to reduce hypertension reliably, but not tachycardia.
– Dihydropyridine agents such as nifedipine should be avoided, as reflex tachycardia may occur.
– The alpha-blocker phentolamine has been recommended but only treats alpha-mediated hypertension and not tachycardia. -
This question is part of the following fields:
- Pharmacology
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Question 18
Correct
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A 55-year-old diabetic male presents with a feeling of generally being unwell. He also has a history of atrial fibrillation and epilepsy. His main complaint is a blue tinge to his vision. Which one of his medications is most likely to be responsible?
Your Answer: Sildenafil
Explanation:Blue tinge of vision/cyanopsia is caused due to the intake of sildenafil citrate.
Sildenafil citrate (Viagra) is the first oral drug to be widely approved for the treatment of erectile dysfunction.
It is a potent and selective inhibitor of type-V phosphodiesterase, the primary form of the enzyme found in human penile erectile tissue, thereby preventing the breakdown of cyclic guanosine monophosphate (cGMP), the intracellular second messenger of nitric oxide.Uses:
It is used for the treatment of erectile dysfunction, idiopathic pulmonary hypertension, premature ejaculation, high altitude illness, penile rehabilitation after radical prostatectomy, angina pectoris, and lower urinary tract symptoms.Adverse effects:
Mild headache, flushing, dyspepsia, cyanopsia, back pain, and myalgias – due to a high concentration of PDE11 enzyme in skeletal muscle, which shows significant cross-reactivity with the use of tadalafil.
It can also cause hypotension, dizziness, and rhinitis.Note: Xanthopsia (yellow-green vision) may occur secondary to treatment with digoxin.
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This question is part of the following fields:
- Pharmacology
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Question 19
Correct
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A 22-year-old university student is admitted after taking drugs at a night club. Which of the following features suggest she had taken ecstasy (MDMA)?
Your Answer: A pyrexia of 40°C
Explanation:MDMA commonly known as ecstasy or molly, is a psychoactive drug primarily used as a recreational drug. The desired effects include altered sensations, increased energy, empathy, and pleasure. Features of MDMA abuse include hyponatraemia, tachycardia, hyperventilation, and hyperthermia.
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This question is part of the following fields:
- Pharmacology
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Question 20
Correct
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A 73-year-old female is being reviewed in the osteoporosis clinic. She had a fracture of her left hip 5 years ago and was started on alendronate. Following the development of persistent musculoskeletal pain, alendronate was replaced with risedronate, which was also stopped for similar reasons. Strontium ranelate was therefore started but was also stopped due to the development of deep vein thrombosis in the right leg. Her current T-score is -4.1. A decision is made to start a trial of denosumab. What is the mechanism of action of denosumab?
Your Answer: Inhibits RANK ligand, which in turn inhibits the maturation of osteoclasts
Explanation:The principal mechanism by which strontium inhibits osteoclast activity is by enhancing the secretion of osteoprotegerin (OPG) and by reducing the expression of the receptor activator of nuclear factor κB ligand (RANKL) in osteoblasts.
Osteoporosis is defined as low bone mineral density caused by altered bone microstructure ultimately predisposing patients to low-impact, fragility fractures.
Management:
Vitamin D and calcium supplementation should be offered to all women unless the clinician is confident they have adequate calcium intake and are vitamin D replete
Alendronate is the first-line treatment. Around 25% of patients cannot tolerate alendronate, usually due to upper gastrointestinal problems. These patients should be offered risedronate or etidronate.
Strontium ranelate and raloxifene are recommended if patients cannot tolerate bisphosphonates.
Other medications that are useful in the treatment of osteoporosis are denosumab, teriparatide, raloxifene, etc. -
This question is part of the following fields:
- Pharmacology
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Question 21
Incorrect
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A 75-year-old man has presented to the clinic with a complaint of disturbed sleep. The physician has prescribed temazepam. Which of the following best describes the mechanism of action of this drug?
Your Answer: Inhibits the effect gamma-aminobutyric acid
Correct Answer: Enhances the effect of gamma-aminobutyric acid
Explanation:Temazepam is an orally available benzodiazepine used in the therapy of insomnia.
The soporific activity of the benzodiazepines is mediated by their ability to enhance gamma-aminobutyric acid (GABA) mediated inhibition of synaptic transmission through binding to the GABA-A receptor.
The recommended initial dose for insomnia is 7.5 mg before bedtime, increasing as needed to a maximum dose of 30 mg.The most common side effects of temazepam are dose-related and include daytime drowsiness, lethargy, ataxia, dysarthria, and dizziness.
Tolerance develops to these side effects, but tolerance may also develop to the effects on insomnia. -
This question is part of the following fields:
- Pharmacology
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Question 22
Correct
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A 50-year-old farmer, under treatment for depression, presents to the emergency department following an intentional overdose of an unidentified substance. On examination, he was found to be bradycardic, hypotensive, hyper-salivating, and disoriented. On ocular examination, his pupils were found to be miotic. What is the most likely substance he ingested?
Your Answer: An organophosphate insecticide
Explanation:The farmer has most likely ingested an organophosphate insecticide.
Organophosphorus compounds are used widely as:
• Insecticides – Malathion, parathion, diazinon, dichlorvos
• Nerve gases – Soman, sarin, tabun, VX
• Ophthalmic agents – Echothiophate
• Antihelmintics – Trichlorfon
• Herbicides – merphos
• Industrial chemical (plasticizer) – Tricresyl phosphate
Signs and symptoms of Organophosphorus Poisoning (OPP) can be classified as:
• Muscarinic effects:
o Cardiovascular – Bradycardia, hypotension
o Respiratory – Rhinorrhoea, bronchorrhea, bronchospasm, cough, severe respiratory distress
o Gastrointestinal – Hypersalivation, nausea and vomiting, abdominal pain, diarrhoea, faecal incontinence
o Genitourinary – Incontinence
o Ocular – Blurred vision, miosis
o Glands – Increased lacrimation, diaphoresis
• Nicotinic effects:
o Muscle fasciculation, weakness, cramping, diaphragmatic failure, and autonomic side effects include: hypertension, tachycardia, and mydriasis.
• Central nervous system (CNS) effects:
o Anxiety, emotional lability, restlessness, confusion, ataxia, tremors, seizures, coma, apnoea
Mainstay Treatment:
• Decontamination
• Securing Airway, Breathing and Circulation
• Atropine
• Pralidoxime
• Benzodiazepines -
This question is part of the following fields:
- Pharmacology
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Question 23
Correct
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A 78-year-old male with long-standing Alzheimer's disease is being reviewed in your clinic. Which among the following is true regarding memantine, a drug which has been approved for the management of dementia in the UK?
Your Answer: It is an NMDA-receptor agonist
Explanation:Memantine is an antagonist of the NMDA (N-Methyl-D-Aspartate)-receptor subtype of glutamate receptor. It is used to slow the neurotoxicity thought to be involved in Alzheimer’s disease and other neurodegenerative diseases.
Drug interactions:
When given concomitantly with other NMDA-receptor antagonists (e.g., ketamine, amantadine) increase the risk of psychosis.
Dopamine agonists, L-dopa, and anticholinergics enhance effects of memantine.
Antispasmodics (e.g., baclofen) enhance effects, as memantine has some antispasmodic effects.
Drugs excreted by cationic transporters in the kidney (e.g. quinine, cimetidine, ranitidine) reduce excretion.Common adverse effects include dizziness, headache, confusion, diarrhoea, and constipation.
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This question is part of the following fields:
- Pharmacology
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Question 24
Correct
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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: 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 25
Correct
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A 18-year-old female is brought to the emergency department by her boyfriend. He is concerned that she may have taken an overdose of her mom's morphine sulphate pills after being depressed about her mother, who is dying of carcinoma of the breast. Which of the following may point towards his suspicion?
Your Answer: Sweating
Explanation:Excessive sweating points towards a morphine overdose.
Morphine is considered the classic opioid analgesic with which other painkillers are compared. Like other medications in this class, morphine has an affinity for delta, kappa, and mu-opioid receptors.
Most commonly used in pain management, morphine provides major relief to patients afflicted with pain.Among the more common adverse effects of morphine use is constipation. Other side effects include nausea, vomiting, drowsiness, and confusion. Psychological and physical dependence may occur.
Other side effects include bronchospasm, angioedema, urinary retention, ureteric or biliary spasm, dry mouth, sweating, rash, facial flushing, vertigo, tachycardia, bradycardia, palpitations, orthostatic hypotension, hypothermia, restlessness, mood change, hallucinations, seizures (adults and children) and miosis, headache and allergic reactions (including anaphylaxis) and decreased libido or potency.
Raised intracranial pressure occurs in some patients. Muscle rigidity may occur with high doses. Elevated liver enzymes may occur due to biliary sphincter constriction. Large doses can lead to respiratory depression, circulatory failure, and coma.
Treatment of opioid overdose:
Initial treatment of overdose begins with supportive care.
Naloxone is a pure competitive antagonist of opiate receptors and has no agonistic activity. The drug is relatively safe and can be administered intravenous, intramuscular, subcutaneous or via the endotracheal tube.
Alternatively, nalmefene and naltrexone maybe considered. -
This question is part of the following fields:
- Pharmacology
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Question 26
Correct
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A 70-year-old man presents with nocturia, hesitancy and terminal dribbling of urine. Prostate examination reveals a moderately enlarged prostate with no irregular features and a well-defined median sulcus. Blood investigations show a PSA level of 1.3 ng/mL. Among the options provided below what is the most appropriate management for this patient?
Your Answer: Alpha-1 antagonist
Explanation:Benign Prostatic Enlargement or Hyperplasia (BPE/BPH) is the most probable diagnosis of the patient in question. It is a histological diagnosis characterized by proliferation of the cellular elements of the prostate.
The initial treatment modality of choice is selective alpha 1 antagonists (such as Prazosin, Alfuzosin and Indoramin, and long acting agents like, Terazosin, Doxazosin, etc.) as they provide immediate relief from the bothersome lower urinary tract symptoms (LUTS).
Other treatment modalities include:
• Non-selective alpha blockers: no longer used due to severe adverse effects and the availability of selective alpha 1 blockers.
• 5 alpha reductase inhibitors: Finasteride and Dutasteride, they target the underlying disease process and reduce the overall prostate volume. Thus, reduce the urinary retention and the lower urinary tract symptoms. (They do not provide immediate relief from LUTS and thus are not preferred as first line drugs over alpha 1 antagonists)
• PDE-5 Inhibitors: The long-acting tadalafil has proven to be useful.
• Surgical Treatment modalities: TURP, Prostatectomy, etc. -
This question is part of the following fields:
- Pharmacology
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Question 27
Incorrect
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A 33-year-old electrical technician presents following an overdose. Anticholinergic syndrome is suspected. Which of the following is true?
Your Answer: Physostigmine is the treatment of choice
Correct Answer: Mydriasis occurs
Explanation:Anticholinergic syndrome occurs following overdose with drugs that have prominent anticholinergic activity including tricyclic antidepressants, antihistamines and atropine. Features include dry, warm, flushed skin, urinary retention, tachycardia, mydriasis (dilated pupils) and agitation.
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This question is part of the following fields:
- Pharmacology
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Question 28
Correct
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A 50-year-old man with a history of hyperlipidaemia, currently under treatment with simvastatin 10mg was found to have persistently high cholesterol levels. Previous attempts to increase the dose of simvastatin have resulted in myalgia. Given this history, which one of the following lipid-regulating drugs should definitely be avoided?
Your Answer: Bezafibrate
Explanation:Both fibrates and nicotinic acid have been associated with myositis, especially when combined with a statin. However, the Committee on Safety of Medicines has produced guidance which specifically warns about the concomitant prescription of fibrates with statins concerning muscle toxicity.
Bezafibrate: It is a fibric acid derivative (fibrate) that has been used as a class of agents known to decrease triglyceride levels while substantially increasing HDL-C levels.
Pharmacological effects:
– Increases VLDL catabolism by increasing lipoprotein and hepatic triglyceride lipase.
– Decreases triglyceride synthesis by inhibiting acetyl-CoA reductase.
– Decreases cholesterol synthesis by inhibiting HMG-CoA reductase.Side effects:
– Hypersensitivity
– Primary biliary cirrhosis
– Pre-existing gallbladder disease
– Concurrent use with HMG-CoA inhibitors (statins) can produce myopathy
– Hepatic/renal impairment in a patient warrants dose adjustment as this drug is primarily excreted via the renal mechanism.Contraindications: Concurrent use of MAO inhibitors, hypersensitivity, pre-existing cholestasis, and pregnancy.
Use: It can be used to treat Barth syndrome (characterized by dilated cardiomyopathy, neutropenia (presenting with recurrent infections), skeletal myopathy and short stature)
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This question is part of the following fields:
- Pharmacology
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Question 29
Incorrect
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A 50-year-old male presents to the ER allegedly claiming that he consumed a bottle of antifreeze. Which of the following symptoms is least likely to be associated with this kind of poisoning?
Your Answer: Metabolic acidosis with high anion gap
Correct Answer: Loss of vision
Explanation:Loss of vision after consumption of antifreeze is a characteristic presentation of methanol poisoning.
Pathophysiology of methanol toxicity:
When ingested, methanol is absorbed rapidly via the gastrointestinal tract in less than 10 minutes. Methanol is not protein-bound and is absorbed directly into the total body water compartment.
Metabolism occurs mainly in the liver through serial oxidation via alcohol dehydrogenase and aldehyde dehydrogenase but begins with alcohol dehydrogenase present in the gastric mucosa.
Alcohol dehydrogenase oxidizes methanol to formaldehyde, and aldehyde dehydrogenase subsequently oxidizes formaldehyde to formic acid.
Formic acid is the primary toxic metabolite that accounts for the associated anion gap metabolic acidosis and end-organ damage.Clinical presentation:
Patients who present within the first 12 to 24 hours following ingestion may appear normal, and this is described as the latent period.
Nausea, vomiting, and abdominal pain subsequently ensue, followed by CNS depression and hyperventilation due to metabolic acidosis.
Ocular symptoms associated with retinal toxicity are often evident in the form of blurry vision, decreased visual acuity, photophobia, and “halo vision.”Treatment:
Treatment options for methanol toxicity include supportive care, fomepizole (Antizole, 4-Methylpyrazole or 4MP), ethanol, dialysis, and folate. -
This question is part of the following fields:
- Pharmacology
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Question 30
Correct
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Which of the following is correct regarding lead poisoning?
Your Answer: Causes a peripheral neuropathy due to demyelination
Explanation:Lead can be absorbed through the skin and by inhalation. It is associated with iron deficiency and a microcytic anaemia. The most common gastrointestinal symptoms are abdominal colic and constipation.
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This question is part of the following fields:
- Pharmacology
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