Open-label study in two parallel groups of 20 healthy subjects each. Group A assessed the effect of CBZ on ESL pharmacokinetics, and Group B assessed the effect of ESL on CBZ pharmacokinetics.

Open-label study in two parallel groups of 20 healthy subjects each. Group A assessed the effect of CBZ on ESL pharmacokinetics, and Group B assessed the effect of ESL on CBZ pharmacokinetics. Each patient participated in the study for approximately 9 weeks. The clinical portion of the study was completed in approximately 3 months. Subjects received the treatments during 35 days.

Inclusion Criteria:

• Male and female subjects aged 18 to 45 years inclusive;
• Body mass index (BMI) between 18 and 30 kg/m2 inclusive;
• Healthy as determined by pre-study medical history, physical examination, vital signs, and 12-lead electrocardiogram (ECG); negative tests for Hepatitis B surface Antigen (HBsAg), anti-HCVAb and Human Immunodeficiency Virus (HIV)-1 and HIV-2 Ab at screening;
• Clinical laboratory test results clinically acceptable at screening and admission to each treatment period;
• Negative screen for alcohol and drugs of abuse at screening and admission to each treatment period;
• Non-smokers or ex-smokers;
• Able and willing to give written informed consent;
• If female, not of childbearing potential by reason of surgery or, if of childbearing potential, she used a double-barrier method of contraception: 1 male barrier method [male condom] plus 1 female barrier method (diaphragm, spermicide, or intrauterine device);
• If female, had a negative urine pregnancy test at screening and admission to each treatment period.

Exclusion Criteria:

• 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; have a clinically relevant surgical history;
• History of relevant atopy or any drug hypersensitivity (including known hypersensitivity to ESL or other carboxamide derivatives [e.g., carbamazepine, oxcarbazepine] or any of its excipients; known hypersensitivity to drugs structurally related to carbamazepine [e.g.: tricyclic antidepressants] or any of its excipients);
• Second or third-degree atrioventricular blockade not corrected with a pace-maker or any other clinically significant abnormality in the 12-lead ECG as determined by the investigator;
• History of alcoholism or drug abuse;
• Consumed more than 14 units1 of alcohol a week;
• Significant infection or known inflammatory process on screening or admission to each treatment period;
• Acute gastrointestinal symptoms (e.g., nausea, vomiting, diarrhoea, heartburn) at the time of screening or admission to each treatment period;
• Use of medicines within two weeks of admission to first period that may affect the safety or other study assessments, in the investigator's opinion;
• Had donated or received any blood or blood products within the 3 months prior to screening;
• Vegetarians, vegans or have other medical dietary restrictions;
• Could not communicate reliably with the investigator; was unlikely to co-operate with the requirements of the study;
• Unwilling or unable to give written informed consent;
• If female, was pregnant or breast-feeding;
• If female, was of childbearing potential and did not use an accepted effective contraceptive method or used hormonal contraceptives;
• Had received an investigational drug within 3 months of screening or was currently participating in another study.