Tinidazole and Ketoconazole Topical: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Tinidazole
Ketoconazole Topical
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Elevated plasma concentrations of tinidazole
Interaction Deep Dive
Tinidazole is metabolized mainly by the CYP3A4 isozyme. Coadministration with ketoconazole, a CYP3A4 inhibitor, may result in elevated plasma concentrations of tinidazole due to decreased metabolism and plasma clearance of tinidazole1. If these agents are used concurrently, consider monitoring patients for increased potential for tinidazole-related adverse reactions, such as altered taste sense, nausea, constipation, anorexia, or weaknesses/fatigue/malaise.
Why it happens (mechanism)
Decreased CYP3A4-mediated metabolism of tinidazole by ketoconazole, leading to a prolonged half-life and reduced plasma clearance of tinidazole
Common questions
Can I take Tinidazole and Ketoconazole Topical together?
Elevated plasma concentrations of tinidazole Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tinidazole and Ketoconazole Topical interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Tinidazole or Ketoconazole Topical need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (1)
- Product Information: TINDAMAX(R) oral tablets, tinidazole oral tablets. Mission Pharmacal Company, San Antonio, TX, 2007. DailyMed
Keep reading about Tinidazole
Keep reading about Ketoconazole Topical
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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