Clarithromycin and Quinine interaction
Clarithromycin and Quinine: the Quinine prescribing label flags 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 Quinine (QUININE SULFATE) label · effective 2025-10-31
The use of macrolide antibiotics such as erythromycin should be avoided in patients receiving quinine sulfate.
Therefore, concomitant administration of macrolide antibiotics such as erythromycin or troleandomycin with quinine sulfate should be avoided [see WARNINGS AND PRECAUTIONS ( 5.3 )] .
Although a causal relationship between a specific drug and the arrhythmia was not established in this case, erythromycin is a CYP3A4 inhibitor and has been shown to increase quinine plasma levels when used concomitantly.
A related macrolide antibiotic, troleandomycin, has also been shown to increase quinine exposure in a pharmacokinetic study [see DRUG INTERACTIONS ( 7.1 )] .
Ketoconazole (CYP3A4 Inhibitor) In a crossover study, healthy subjects (N=9) who received a single oral dose of quinine hydrochloride (500 mg) concomitantly with ketoconazole (100 mg twice daily for 3 days) had a mean quinine AUC that was higher by 45% and a mean oral clearance of quinine that was 31% lower than after receiving quinine alone.
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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.