Istradefylline has 10 known drug interactions based on U.S. FDA drug labeling data. Of these, 4 are contraindicated combinations that should be avoided entirely. 3 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Carbamazepine, Phenytoin, Rifampin. Patients taking Istradefylline should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 10
- Contraindicated
- 4
- Major
- 3
- Moderate
- 2
- Minor
- 1
Contraindicated (4)
- Istradefylline + Carbamazepine— Strong CYP3A4 inducer. Avoid concomitant use with istradefylline.
- Istradefylline + Phenytoin— Strong CYP3A4 inducer. Avoid concomitant use with istradefylline.
- Istradefylline + Rifampin— Strong CYP3A4 inducer decreases istradefylline Cmax by 45% and AUC by 81%. Avoid concomitant use.
- Istradefylline + St. John'S Wort— Strong CYP3A4 inducer. Avoid concomitant use with istradefylline.
Major (3)
- Istradefylline + Clarithromycin— Strong CYP3A4 inhibitor. Recommended maximum dosage of istradefylline is 20 mg once daily with concomitant use.
- Istradefylline + Itraconazole— Strong CYP3A4 inhibitor. Recommended maximum dosage of istradefylline is 20 mg once daily with concomitant use.
- Istradefylline + Ketoconazole— Strong CYP3A4 inhibitor increases istradefylline AUC by 2.5-fold. Recommended maximum dosage is 20 mg once daily.
Moderate (2)
- Istradefylline + Atorvastatin— CYP3A4 substrate. Istradefylline 40 mg increases atorvastatin Cmax and AUC by 1.5-fold. Monitor for increased adverse re…
- Istradefylline + Digoxin— P-glycoprotein substrate. Istradefylline increases digoxin Cmax by 33% and AUC by 21%. Monitor for increased adverse rea…
Minor (1)
- Istradefylline + Midazolam— CYP3A4 substrate. Istradefylline 20 mg did not affect midazolam exposure.