Drug Interaction Study of Tegretol (Carbamazepine) and St. John's Wort in Normal Volunteers
St. John's Wort is a popular dietary supplement that many patients-including those with epilepsy or seizures-take in addition to their regular medicines to elevate mood or relieve stress. Preliminary research indicates that this supplement can speed the metabolism of the anti-seizure drug Tegretol, causing reduced blood levels of the drug. Patients who take Tegretol to control their seizures may have more frequent seizures if the blood level of the drug drops too low. A recent study shows that this effect is not seen when Tegretol is taken for at least 3 weeks. The present study will examine whether there is a medically important drug interaction between St. John's wort and Tegretol when Tegretol is taken for 1 day.
Normal healthy volunteers between 21 and 65 years old who are not taking medicines that can affect the metabolism of drugs in the liver and have not used St. John's wort for at least 30 days may be eligible for this 25-day study.
Participants will take a 400-mg dose of Tegretol after fasting overnight. Blood samples will be drawn the next day during a 12-hour clinic stay at the following intervals: just before the Tegretol dose and at 1, 2, 4, 6, 8, 10, 24, 34, 48 and 72 hours after the dose. A catheter will be placed in the vein to prevent the need for multiple needle sticks until after the 10-hour sample. After completing the blood sampling, participants will take 300 mg of St. John's wort 3 times a day with meals for 2 weeks. After 2 weeks, another fasting dose of Tegretol will be given and the 72-hour blood study will be repeated.
This study may provide information important for the care of patients with epilepsy who take both Tegretol and St. John's Wort.
|Study Design:||Primary Purpose: Treatment|
|Official Title:||Evaluation of the Effect of St. John's Wort on Single Dose Carbamazepine Pharmacokinetics in Normal Healthy Volunteers|
|Study Start Date:||October 2000|
|Estimated Study Completion Date:||April 2001|
Please refer to this study by its ClinicalTrials.gov identifier: NCT00006395
|United States, Maryland|
|Warren G. Magnuson Clinical Center (CC)|
|Bethesda, Maryland, United States, 20892|