Clarithromycin and Itraconazole interaction
Clarithromycin and Itraconazole: 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
Antifungals: Itraconazole Use With Caution Itraconazole: Both clarithromycin and itraconazole are substrates and inhibitors of CYP3A, potentially leading to a bi-directional drug interaction when administered concomitantly (see also Itraconazole under “Drugs That Affect Clarithromycin Tablets” in the table below).
Clarithromycin may increase the plasma concentrations of itraconazole.
Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged adverse reactions.
Drugs that Affect Clarithromycin Tablets Drug(s) that Affect the Pharmacokinetics of Clarithromycin Tablets Recommendation Comments Antifungals: Itraconazole Use With Caution Itraconazole: Itraconazole may increase the plasma concentrations of clarithromycin.
Clarithromycin and other macrolides are known to inhibit CYP3A and Pgp.
From the Itraconazole (Tolsura) label · effective 2025-04-23
Clarithromycin Monitor for adverse reactions.
Erythromycin Clarithromycin Monitor for adverse reactions.
Cardiac Dysrhythmias : Life-threatening cardiac dysrhythmias and/or sudden death have occurred in patients using certain drugs that are metabolized by human CYP450 enzymes concomitantly with oral itraconazole and/or other CYP3A4 inhibitors.
Cardiac Dysrhythmias Life-threatening cardiac dysrhythmias and/or sudden death have occurred in patients using drugs such as, pimozide, methadone, or quinidine concomitantly with oral itraconazole and/or other CYP3A4 inhibitors.
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.