Istradefylline 40 mg/day increased peak concentrations and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/working day. Consider dose reduction of sensitive CYP3A4 substrates.So, although something could possibly be rated an 'A+', overconsumption/overdoing can convey undesired effects. Class 'B'Th