rifapentine will lessen the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Keep an eye on. Strong CYP3A4 inducers are anticipated to lead to significant decreases in sildenafil plasma amountsSo, Whilst something can be rated an 'A+', overconsumption/overdoing can carry undesired effects. Class 'B