Pharmacology · patient case question

What is the mechanism of action of verapamil?

Patient case: Polypharmacy — Cardiovascular & GI

demo: 68-year-old male

chief: “I need a crown on my lower left molar.”

history: Hypertension, gastroesophageal reflux disease, atrial fibrillation, hyperlipidemia, gout. Non-smoker.

meds: Lisinopril, omeprazole, verapamil, apixaban, rosuvastatin, allopurinol

findings: BP 132/84 mmHg. Generalized attrition. Tooth #19 with fractured MOD amalgam, no pulpal symptoms. No active periodontal disease.

Opens ATP-sensitive potassium channels in vascular smooth muscle
Blocks beta-1 adrenergic receptors in the sinoatrial node
Inhibits the sodium-potassium ATPase in cardiac myocytes
Blocks voltage-dependent calcium channels, reducing calcium influx in cardiac muscle and decreasing workload

Show answer and explanation

Correct answer: D. Blocks voltage-dependent calcium channels, reducing calcium influx in cardiac muscle and decreasing workload

A. Potassium channel opening describes minoxidil, a direct vasodilator.
B. That is a beta blocker such as atenolol. Verapamil slows the heart, but through calcium channels, not adrenergic receptors.
C. Sodium-potassium ATPase inhibition is the mechanism of digoxin.
D. Correct. Verapamil is a non-dihydropyridine calcium channel blocker with strong cardiac selectivity; reduced calcium entry lowers contractility, heart rate, and myocardial workload.