DO Osteopathic Pharmacology 1 — Questions and Answers
Question 1: Which drug class is the first-line treatment for hypertension in a patient with type 2 diabetes and proteinuria?
- Beta-blockers
- ACE inhibitors (Correct answer)
- Calcium channel blockers
- Thiazide diuretics
Correct answer: ACE inhibitors
ACE inhibitors reduce intraglomerular pressure and have renoprotective effects in diabetic nephropathy by blocking the renin-angiotensin-aldosterone system.
Question 2: A patient stabilized on warfarin is started on rifampin for latent TB. What is the expected effect on INR?
- INR increases significantly
- INR decreases significantly (Correct answer)
- INR remains unchanged
- INR fluctuates unpredictably
Correct answer: INR decreases significantly
Rifampin is a potent CYP450 inducer that accelerates warfarin metabolism, significantly reducing INR and increasing clot risk.
Question 3: Which opioid analgesic is contraindicated in renal failure due to accumulation of a toxic active metabolite?
- Fentanyl
- Methadone
- Morphine (Correct answer)
- Buprenorphine
Correct answer: Morphine
Morphine-6-glucuronide, a potent active metabolite, accumulates in renal failure and causes prolonged sedation and respiratory depression.
Question 4: A patient receiving IV vancomycin develops flushing and erythema over the face, neck, and chest. What is the mechanism?
- IgE-mediated allergic reaction
- Direct mast cell degranulation causing histamine release (Correct answer)
- Complement system activation
- T-cell mediated delayed hypersensitivity
Correct answer: Direct mast cell degranulation causing histamine release
Red man syndrome results from non-immune direct mast cell degranulation and histamine release, which is rate-dependent and not a true allergy.
Question 5: Which beta-blocker is most cardioselective and preferred when a beta-blocker is necessary in a patient with mild COPD?
- Propranolol
- Carvedilol
- Metoprolol (Correct answer)
- Labetalol
Correct answer: Metoprolol
Metoprolol selectively blocks beta-1 receptors with minimal beta-2 activity, reducing the risk of bronchospasm compared to non-selective agents.
Question 6: A woman on oral contraceptives is prescribed an antibiotic for a UTI. Which antibiotic poses the greatest risk of reducing OCP efficacy?
- Nitrofurantoin
- Rifampin (Correct answer)
- Trimethoprim-sulfamethoxazole
- Cephalexin
Correct answer: Rifampin
Rifampin strongly induces CYP3A4, dramatically increasing the hepatic metabolism of estrogen and progestin components of OCPs.
Question 7: Probenecid is sometimes co-administered with penicillin to enhance its therapeutic effect. What is the pharmacokinetic mechanism?
- Probenecid inhibits renal tubular secretion of penicillin (Correct answer)
- Probenecid inhibits penicillinase enzymes in bacteria
- Probenecid increases intestinal absorption of penicillin
- Probenecid displaces penicillin from plasma protein binding
Correct answer: Probenecid inhibits renal tubular secretion of penicillin
Probenecid blocks OAT (organic anion transporter) proteins in the proximal tubule, reducing secretion of penicillin into the urine and prolonging its half-life.
DO Osteopathic Pharmacology 1
Which drug class is the first-line treatment for hypertension in a patient with type 2 diabetes and proteinuria?