Does Phenytoin Interact with Tinidazole?
Phenytoin and Tinidazole have a moderate drug interaction according to U.S. FDA drug labeling data. Concomitant administration may result in prolongation of phenytoin half-life and reduction in clearance. Adjustment of anticonvulsant and/or tinidazole doses may be needed. The mechanism involves prolongation of phenytoin half-life and reduced clearance. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Moderate
- Phenytoin Class
- Anti-epileptic Agent
- Tinidazole Class
- Nitroimidazole Antimicrobial
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Phenytoin and Tinidazole occurs because prolongation of phenytoin half-life and reduced clearance. Clinically, this means concomitant administration may result in prolongation of phenytoin half-life and reduction in clearance. adjustment of anticonvulsant and/or tinidazole doses may be needed. This is classified as a moderate interaction. While it may not require stopping either medication, your healthcare provider should be aware you are taking both so they can monitor for potential effects and adjust treatment if necessary.
What To Tell Your Doctor or Pharmacist
If you are taking Phenytoin and your doctor is considering prescribing Tinidazole (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider