Does Nitisinone Interact with Sensitive Cyp3a Substrates?
Nitisinone and Sensitive Cyp3a Substrates have a major drug interaction according to U.S. FDA drug labeling data. Nitisinone is a moderate CYP2C9 inhibitor that may increase exposure of co-administered drugs metabolized by CYP2C9, requiring dosage reduction by half and additional adjustments to maintain therapeutic concentrations. The mechanism involves cyp2c9 inhibition. 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
- Major
- Nitisinone Class
- 4-Hydroxyphenyl-Pyruvate Dioxygenase Inhibitor
- Management
- Close medical supervision required
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Nitisinone and Sensitive Cyp3a Substrates occurs because cyp2c9 inhibition. Clinically, this means nitisinone is a moderate cyp2c9 inhibitor that may increase exposure of co-administered drugs metabolized by cyp2c9, requiring dosage reduction by half and additional adjustments to maintain therapeutic concentrations. This is classified as a major interaction, meaning it could cause serious harm if not properly managed. Your healthcare provider may need to adjust dosages, substitute one medication, or increase monitoring frequency.
What To Tell Your Doctor or Pharmacist
If you are taking Nitisinone and your doctor is considering prescribing Sensitive Cyp3a Substrates (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 how frequently you should be monitored while these are co-prescribed
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider