Article Text
Summary
In the elderly, calcium-channel blockers are the first-line treatment for hypertension, and macrolides are commonly prescribed antibiotics. Here we report a 78-year-old man taking nifedipine, diltiazem and carvedilol who presented with persistent hypotension and bradycardia after clarithromycin was prescribed. He was diagnosed with drug-induced hypotension and treated with fluid resuscitation and vasoactive agents. His symptoms gradually improved. He was transferred out of the intensive care unit 3 days after hospitalisation. Combining calcium-channel blockers and clarithromycin can cause vasodilatory hypotension. The concomitant use of calcium-channel blockers and macrolide antibiotics increases the levels of calcium-channel blockers in the blood as they are metabolised by cytochrome P450 3A4 (CYP3A4), which is inhibited by macrolide antibiotics. Moreover, the addition of another calcium-channel blocker and a β blocker can lower cardiac output due to bradycardia and worsen hypotension. Therefore, it is important to consider drug interactions when the cause of hypotension is unknown.
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Footnotes
Contributors ST and YK wrote and edited the case report. TT had the idea for this case report and was involved in the review.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.