Istradefylline forty mg/working day elevated peak amounts and AUC of CYP3A4 substrates in scientific trials. This effect wasn't noticed with istradefylline twenty mg/working day. Consider dose reduction of delicate CYP3A4 substrates.Watch Closely (one)carvedilol will increase effects of sildenafil by additive vasodilation. Use Warning/Observe. Sild