Cimetidine and Hydroxychloroquine interaction
Cimetidine and Hydroxychloroquine: the Hydroxychloroquine prescribing label 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 Hydroxychloroquine (Plaquenil) label · effective 2026-04-09
Avoid concomitant use of cimetidine 7.9 Rifampicin Lack of efficacy of hydroxychloroquine was reported when rifampicin was concomitantly administered.
Cimetidine Concomitant use of cimetidine resulted in a 2-fold increase of exposure of chloroquine, which is structurally related to hydroxychloroquine.
Interaction of cimetidine with hydroxychloroquine cannot be ruled out.
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.