Cimetidine and Doxazosin interaction
Cimetidine and Doxazosin: the Doxazosin prescribing label describes an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Doxazosin (Doxazosin mesylate) label · effective 2025-11-24
Cimetidine: In healthy volunteers, the administration of a single 1 mg dose of doxazosin on day 1 of a four-day regimen of oral cimetidine (400 mg twice daily) resulted in a 10% increase in mean AUC of doxazosin, and a slight but not significant increase in mean C max and mean half-life of doxazosin.
Strong cytochrome P450 (CYP) 3A inhibitors may increase exposure to doxazosin and increased risk of hypotension.
Strong CYP3A inhibitors may increase exposure to doxazosin.
Monitor blood pressure and for symptoms of hypotension when Doxazosin is used concomitantly with strong CYP3A inhibitors [see Clinical Pharmacology (12.3) ].
Drug Interactions There are only limited data on the effects of drugs known to influence the hepatic metabolism of doxazosin (e.g., cimetidine).
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.