Istradefylline 40 mg/day enhanced peak ranges and AUC of CYP3A4 substrates in clinical trials. This effect wasn't observed with istradefylline 20 mg/day. Look at dose reduction of sensitive CYP3A4 substrates.Ergotamine: Alpha-adrenergic blocking agent with direct stimulating effect on sleek muscle of peripheral and cranial blood vessels; also elici