Metronidazole and Tinidazole interaction
Metronidazole and Tinidazole: the Tinidazole 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 Tinidazole label · effective 2025-12-01
WARNING: POTENTIAL RISK FOR CARCINOGENICITY WARNING: POTENTIAL RISK FOR CARCINOGENICITY Carcinogenicity has been seen in mice and rats treated chronically with metronidazole, another nitroimidazole agent [see Nonclinical Toxicology (13.1)].
Carcinogenicity has been seen in mice and rats treated chronically with metronidazole, another nitroimidazole agent (13.1).
Severe irreversible hepatotoxicity/acute liver failure with fatal outcomes have been reported after initiation of metronidazole, another nitroimidazole drug, structurally related to tinidazole, in patients with Cockayne syndrome [see Adverse Reactions (6.2)] Prior history of hypersensitivity to tinidazole or other nitroimidazole derivatives (4, 6.1, 6.2)
The following drug interactions were reported for metronidazole, a chemically-related nitroimidazole and may therefore occur with tinidazole: Warfarin and other oral coumarin anticoagulants: Anticoagulant dosage may need adjustment during and up to 8 days after tinidazole therapy ( 7.1 )
Potential Effects of Tinidazole on Other Drugs Warfarin and Other Oral Coumarin Anticoagulants: As with metronidazole, tinidazole may enhance the effect of warfarin and other coumarin anticoagulants, resulting in a prolongation of prothrombin time.
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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.