Clarithromycin and Tolterodine interaction
Clarithromycin and Tolterodine: 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 Clarithromycin label · effective 2026-01-01
Lurasidone: [See Contraindications ( 4.7 )] Antispasmodics: Tolterodine (patients deficient in CYP2D6 activity) Use With Caution Tolterodine: The primary route of metabolism for tolterodine is via CYP2D6.
In this population subset, inhibition of CYP3A results in significantly higher serum concentrations of tolterodine.
Tolterodine 1 mg twice daily is recommended in patients deficient in CYP2D6 activity (poor metabolizers) when co-administered with clarithromycin.
From the Tolterodine (Detrol) label · effective 2023-02-15
Drug Interactions CYP3A4 Inhibitors Ketoconazole, an inhibitor of the drug metabolizing enzyme CYP3A4, significantly increased plasma concentrations of tolterodine when coadministered to subjects who were poor metabolizers (see CLINICAL PHARMACOLOGY, Variability in Metabolism and Drug-Drug Interactions ).
For patients receiving ketoconazole or other potent CYP3A4 inhibitors such as other azole antifungals (e.g., itraconazole, miconazole) or macrolide antibiotics (e.g., erythromycin, clarithromycin) or cyclosporine or vinblastine, the recommended dose of DETROL is 1 mg twice daily (see DOSAGE AND ADMINISTRATION ).
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.