Doxazosin and Itraconazole interaction

Doxazosin and Itraconazole: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Itraconazole (Tolsura) label · effective 2025-04-23

Major

…that Affect Concomitant Drug Concentrations Concomitant Drug Within Class Prevention or Management Drug Interactions with TOLSURA that Increase Concomitant Drug Concentrations and May Increase Risk of Adverse Reactions Associated with the Concomitant Drug Alpha Blockers Alfuzosin Silodosin Tamsulosin Not recommended during and 2 weeks after TOLSURA treatment.

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From the Doxazosin (Doxazosin mesylate) label · effective 2025-11-24

Moderate

Strong cytochrome P450 (CYP) 3A inhibitors may increase exposure to doxazosin and increased risk of hypotension.

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Moderate

Strong CYP3A inhibitors may increase exposure to doxazosin.

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Moderate

Monitor blood pressure and for symptoms of hypotension when Doxazosin is used concomitantly with strong CYP3A inhibitors [see Clinical Pharmacology (12.3) ].

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Minor

CYP 3A Inhibitors In vitro studies suggest that doxazosin is a substrate of CYP 3A4.

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Not 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.