Doxazosin and Ketoconazole interaction
Doxazosin and Ketoconazole: both prescribing labels describe 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
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) ].
CYP 3A Inhibitors In vitro studies suggest that doxazosin is a substrate of CYP 3A4.
From the Ketoconazole label · effective 2026-07-07
Alpha Blockers tamsulosin Analgesics methadone alfentanil, buprenorphine IV and sublingual, fentanyl, oxycodone, sufentanil Methadone: The potential increase in plasma concentrations of methadone when coadministered with ketoconazole tablets may increase the risk of serious cardiovascular events including QT prolongation and torsade de pointes, or respiratory…
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.