Effekten af sildenafil bør overvåges nøje hos patienter, der samtidigt anvender potente CYP3A4 - induktorer som carbamazepin, phenytoin, phenobarbital, prikbladet perikon og rifamipicin.
Efficacy of sildenafil should be closely monitored in patients using concomitant potent CYP3A4 inducers, such as carbamazepine, phenytoin, phenobarbital, St John’ s wort and rifamipicine.