Bosentan markedly reduces the AUC of sildenafil (by about 70%) and modestly reduces the AUC of
tadalafil (by about 40%).
Bosentan levels are modestly reduced by sildenafil and not affected to a clinically relevant extent by
tadalafil.
The
efficacy of sildenafil and possibly
tadalafil may be reduced in patients taking bosentan, whereas the effects of
bosentan may be increased in those taking sildenafil (but probably not tadalafil). The outcome of concurrent use should be closely monitored.