rifapentine will lower the extent or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Keep an eye on. Strong CYP3A4 inducers are expected to result in considerable decreases in sildenafil plasma rangesStiripentol is actually a CYP3A4 inhibitor and inducer. Check CYP3A4 substrates coadministered with stiripe