The Effect of BIA 2-093 on the Steady-state Pharmacokinetics of Digoxin

Inclusion Criteria: * Male or female subjects aged between 18 and 45 years, inclusive. * Subjects of body mass index (BMI) between 19 and 28 kg/m2, inclusive. * Subjects who were healthy as determined by pre-study medical history, physical examination, neurological examination, and 12-lead ECG. * Subjects who had clinical laboratory tests clinically acceptable. * Subjects who were negative for HBs Ag, anti-HCV Ab and anti-HIV-1 and HIV-2 Ab tests at screening. * Subjects who were negative for alcohol and drugs of abuse at screening. * Subjects who were non-smokers or who smoked less than 10 cigarettes or equivalent per day. * Subjects who were able and willing to give written informed consent. * In case of female volunteers, subjects who were not of childbearing potential by reason of surgery or, if of childbearing potential, used one of the following methods of contraception: double-barrier or intrauterine device. * In case of female volunteers, subjects who had a negative pregnancy test at screening. Exclusion Criteria: * Subjects who did not conform to the above inclusion criteria. * Subjects who had a clinically relevant history or presence of respiratory, gastrointestinal, renal, hepatic, haematological, lymphatic, neurological, cardiovascular, psychiatric, musculoskeletal, genitourinary, immunological, dermatological, endocrine, connective tissue diseases or disorders. * Subjects who had a clinically relevant surgical history. * Subjects who had a clinically relevant family history. * Subjects who had a history of relevant atopy. * Subjects who had a history of relevant drug hypersensitivity. * Subjects who had a history of alcoholism or drug abuse. * Subjects who consumed more than 14 units of alcohol a week. * Subjects who had any of the following findings on the ECG: QTc interval \>440 msec; first-, second- or third-degree atrioventricular block; atrial fibrillation; heart rate below 50 bpm; any other relevant abnormality. * Subjects who had a significant infection or known inflammatory process on screening and/or admission. * Subjects who had acute gastrointestinal symptoms at the time of screening and/or admission (e.g., nausea, vomiting, diarrhoea, heartburn). * Subjects who had used prescription drugs within 4 weeks of first dosing. * Subjects who had used over the counter medication excluding oral routine vitamins but including mega dose vitamin therapy within one week of first dosing. * Subjects who had used any investigational drug and/or participated in any clinical trial within 2 months of their first admission. * Subjects who had previously received BIA 2-093. * Subjects who had donated and/or received any blood or blood products within the previous 2 months prior to screening. * Subjects who were vegetarians, vegans and/or had medical dietary restrictions. * Subjects who could not communicate reliably with the investigator. * Subjects who were unlikely to co-operate with the requirements of the study. * Subjects who were unwilling or unable to give written informed consent. * In case of female volunteers, subjects who were pregnant or breast-feeding. * In case of female volunteers, subjects who were of childbearing potential and did not use an authorized effective contraceptive method.