Alosetron and Ketoconazole interaction
Alosetron and Ketoconazole: the Alosetron prescribing label 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 Alosetron (LOTRONEX) label · effective 2026-06-30
Ketoconazole increased mean alosetron plasma concentrations (AUC) by 29%.
Caution should be used when alosetron and ketoconazole are administered concomitantly.
CYP3A4 inhibitors: Use with caution in combination due to increased exposure of alosetron.
Coadministration of alosetron and strong CYP3A4 inhibitors such as clarithromycin, telithromycin, protease inhibitors, voriconazole, and itraconazole has not been evaluated but should be undertaken with caution because of similar potential drug interactions.
In a pharmacokinetic study, 38 healthy female subjects received ketoconazole 200 mg twice daily for 7 days, with coadministration of alosetron 1 mg on the last day.
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.