Gabapentin Treatment of Benzodiazepine Abuse in Methadone Maintenance Patients

The investigators will recruit individuals with current benzodiazepine abuse or dependence, as defined by the DSM-IV, who are receiving methadone maintenance treatment at the Bridge Plaza Treatment and Rehabilitation Clinic. The initial step in recruitment for all patients will be a referral from a clinic counselor.

The investigators plan to enroll 86 participants into the study. Both males and females will be recruited. The distribution of benzodiazepine abuse in methadone maintenance populations with regard to race and gender is not well studied.The investigators expect the gender and racial distribution of subjects to reflect the demographic nature of the Bridge Plaza Treatment and Rehabilitation Clinic; which is approximately 33% Caucasian, 33% African-American, and 33% Hispanic; and 40% female. The investigators will make every effort to recruit minority patients in order to ensure the ability to generalize our findings to the overall treatment population.

All patients will begin medication at the start of the study. Subjects will take medication twice each day, once in the morning and once in the evening. All tablets (placebo and study medication) will be over-capsulated with riboflavin to measure compliance. The placebo group will have a dosing schedule that is identical to the gabapentin group (i.e., they will take the same number of pills each day). Medication will be dispensed weekly in individual vials identified by patient, with dosing instructions written on the outside of the vials. Patients in the placebo group will not receive gabapentin at any time during the study. Gabapentin will be administered in 400 mg tablets; placebo tablets will appear identical to the gabapentin tablets. Gradual increases in medication doses are used in order to minimize side effects and enhance compliance. At the start of week 1, the group receiving gabapentin will be administered at 400 mg three-times a day. This dose will be increased to 800 mg three-times a day at week 2 and increased to 1200 mg three-times a day at the start of week 3. The dose will continue at 1200 mg three-times a day for weeks 3 through 8. Dose reductions for tolerability will be made by the research psychiatrist in coordination with the research pharmacy. All patients must take a minimum of gabapentin/placebo 400 mg BID to remain in the study.

Both the active and placebo medication capsules will contain riboflavin, which will allow the clinic to verify that the study medication is being taken correctly and absorbed by the body. Urine samples obtained weekly will be examined under a UV lamp in order to observe any fluorescence signifying the consumption of the study capsules. The patient will consume approximately 100 mg of riboflavin daily.

The goal of compliance enhancement therapy is to achieve high quality supportive treatment as well as consistency between treatment groups. Treatment will be delivered in 9 individual sessions over 9 weeks. Sessions will last approximately 30 minutes and will be structured, focused on setting abstinence from benzodiazepine use as a goal, patient compliance, and current functioning. The therapist will promote a positive supportive therapeutic relationship with the treatment goal of encouraging abstinence from benzodiazepines and adherence to study visits and medication.