This study was an open label, three period, fixed sequence study in healthy male and female subjects performed under fasting conditions at a single study center.~The study comprised:~Screening during Days -28 to -2 (both inclusive).~Three treatment periods separated by a washout period of at least 10 days.~Duration of Treatment:~The duration of participation for each subject was approximately 2 months and 3 weeks (including the screening period).
The purpose of this study is:~To assess the effect of BIA 5 1058 400 mg on the pharmacokinetics (PK) of sildenafil.~To assess the effect of sildenafil on the PK of BIA 5-1058.