Selegiline Hydrochloride Phenytoin Sodium
ModeratePhenytoin can lower the levels and effects of several medicines, and selegiline is one of them. The list in the leaflet includes clozapine, ciclosporin, tacrolimus, bupropion, amiodarone, celecoxib, citalopram, benzodiazepines, digoxin, itraconazole, levodopa, neuromuscular-blocking agents, thyroid hormones and topiramate. Selegiline is named as a CYP2B6 substrate, so phenytoin can make it work less well. CYP2C8, CYP2C9, CYP2C19 and CYP3A4 substrates are also affected, so the drugs that are broken down by those enzymes may be less effective when taken with phenytoin.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.