ABPS ABPS Pharmacology & Therapeutics 2 — Questions and Answers
Question 1: Which antibiotic class should be avoided in children under 8 years of age due to risk of permanent dental staining?
- Penicillins
- Cephalosporins
- Tetracyclines (Correct answer)
- Macrolides
Correct answer: Tetracyclines
Tetracyclines bind to calcium in developing teeth and bone, causing permanent yellow-gray-brown discoloration and enamel hypoplasia in children under 8.
Question 2: A patient develops QT prolongation after starting azithromycin. Which co-prescribed medication most likely contributed to this risk?
- Amoxicillin
- Metoprolol
- Haloperidol (Correct answer)
- Lisinopril
Correct answer: Haloperidol
Haloperidol independently prolongs the QT interval, and combining it with azithromycin—which also prolongs QT—dramatically increases the risk of torsades de pointes.
Question 3: When prescribing ACE inhibitors, which electrolyte abnormality must be monitored closely?
- Hyponatremia
- Hyperkalemia (Correct answer)
- Hypomagnesemia
- Hypocalcemia
Correct answer: Hyperkalemia
ACE inhibitors reduce aldosterone secretion, decreasing renal potassium excretion and increasing the risk of life-threatening hyperkalemia.
Question 4: A patient with gout is started on allopurinol. What is the primary mechanism of action of this medication?
- Blocks renal reabsorption of urate
- Inhibits xanthine oxidase to reduce uric acid synthesis (Correct answer)
- Promotes urinary excretion of uric acid
- Blocks urate crystal deposition in joints
Correct answer: Inhibits xanthine oxidase to reduce uric acid synthesis
Allopurinol inhibits xanthine oxidase, the enzyme responsible for converting hypoxanthine and xanthine to uric acid, thereby reducing its production.
Question 5: Which medication used for osteoporosis must be taken with a full glass of water and the patient must remain upright for at least 30 minutes after ingestion?
- Raloxifene
- Alendronate (Correct answer)
- Calcitonin
- Denosumab
Correct answer: Alendronate
Alendronate, a bisphosphonate, can cause severe esophageal irritation and ulceration if it remains in contact with esophageal mucosa, requiring the patient to remain upright after dosing.
Question 6: A patient on digoxin develops toxicity. Which electrolyte imbalance is most likely to have precipitated this?
- Hypernatremia
- Hyperkalemia
- Hypokalemia (Correct answer)
- Hypercalcemia
Correct answer: Hypokalemia
Hypokalemia potentiates digoxin toxicity because potassium and digoxin compete for binding on the Na+/K+-ATPase pump, and low potassium levels increase digoxin's binding affinity.
ABPS ABPS Pharmacology & Therapeutics 2
Which antibiotic class should be avoided in children under 8 years of age due to risk of permanent dental staining?