A patient is prescribed a calcium channel blocker (e.g., amlodipine) for hypertension. Which antibiotic commonly prescribed by dentists should be AVOIDED or used with caution due to a significant drug interaction?

Clarithromycin is a macrolide antibiotic that is a potent inhibitor of cytochrome P450 3A4 (CYP3A4), the primary enzyme responsible for metabolizing most calcium channel blockers (amlodipine, nifedipine, verapamil, diltiazem). When clarithromycin is co-administered, it significantly reduces the metabolism of the calcium channel blocker, causing increased plasma concentrations, excessive vasodilation, hypotension, reflex tachycardia, and potentially serious adverse effects. This is a clinically significant drug interaction. Azithromycin is a weak CYP3A4 inhibitor with minimal interaction. Amoxicillin does not inhibit CYP enzymes and has no significant interaction with calcium channel blockers.