SMLE Pharmacology 3

Question 1

A patient presents with organophosphate poisoning showing excessive salivation, lacrimation, urination, diarrhoea, and miosis. What is the antidote?

Accepted Answer

Atropine and pralidoxime

Answer

Organophosphate poisoning causes cholinergic crisis by irreversibly inhibiting acetylcholinesterase. Atropine (muscarinic antagonist) treats secretions and bradycardia, while pralidoxime (2-PAM) reactivates acetylcholinesterase if given early (before 'ageing' of the enzyme-inhibitor complex).

Question 2

A patient on long-term corticosteroids is to undergo surgery. What perioperative consideration is essential?

Accepted Answer

Stress-dose steroids (hydrocortisone) perioperatively

Answer

Chronic corticosteroid use suppresses the hypothalamic-pituitary-adrenal (HPA) axis. During surgical stress, the adrenal glands cannot mount an appropriate cortisol response, risking adrenal crisis. Stress-dose hydrocortisone (50-100 mg IV) is given perioperatively.

Question 3

Which antiemetic is the drug of choice for chemotherapy-induced nausea and vomiting?

Accepted Answer

Ondansetron

Answer

Ondansetron (a 5-HT3 receptor antagonist) is first-line for chemotherapy-induced nausea and vomiting (CINV). It blocks serotonin receptors in the chemoreceptor trigger zone and vagal afferents. For highly emetogenic chemotherapy, it is combined with dexamethasone and aprepitant (NK1 antagonist).

Question 4

A patient is started on amiodarone for atrial fibrillation. Which organ systems require monitoring due to amiodarone toxicity?

Accepted Answer

Thyroid, liver, lungs, and eyes

Answer

Amiodarone has a wide toxicity profile requiring monitoring of: thyroid (hypo/hyperthyroidism due to iodine content), liver (hepatotoxicity), lungs (pulmonary fibrosis), eyes (corneal microdeposits, optic neuropathy), and skin (photosensitivity, blue-grey discolouration).

Question 5

What is the mechanism of action of omeprazole?

Accepted Answer

Irreversible proton pump inhibitor

Answer

Omeprazole irreversibly inhibits the hydrogen-potassium ATPase (proton pump) on the luminal surface of parietal cells in the stomach. This blocks the final common pathway of acid secretion, providing potent and sustained acid suppression.

SMLE Practice Test

SMLE Practice Test

SMLE Pharmacology 3