Da 96% af sildenafil (og dets væsentligste cirkulerende N- desmethylmetabolit) er bundet til plasmaproteiner, resulterer dette i den
Since sildenafil (and its major circulating N- desmethyl metabolite) is 96% bound to plasma proteins, this results in the mean maximum free plasma concentration for sildenafil of 18 ng/ ml (38 nM).