72% af sildenafils efter 20 mg 3 gange dagligt (overført til et 36% bidrag til sildenafils farmakologiske effekt).
In patients with pulmonary arterial hypertension, plasma concentrations of N-desmethyl metabolite are approximately 72% those of sildenafil after 20 mg three times a day dosing (translating into a 36% contribution to sildenafil’ s pharmacological effects).