Clarithromycin and Fluconazole interaction
Clarithromycin and Fluconazole: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Fluconazole label · effective 2026-04-02
Coadministration of other drugs known to prolong the QT interval and which are metabolized via the enzyme CYP3A4 such as erythromycin, pimozide, and quinidine are contraindicated in patients receiving fluconazole.
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).
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.
Clarithromycin and other macrolides are known to inhibit CYP3A.
Fluconazole No Dose Adjustment Fluconazole: [see Pharmacokinetics ( 12.3 )] Anti-Gout Agents: Colchicine (in patients with renal or hepatic impairment) Contraindicated Colchicine: Colchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (Pgp).
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.