Gabapentin Use in a Managed Medicaid Population

OBJECTIVE: The use of gabapentin, an antiepileptic agent, in a primary care setting was evaluated to determine (a) the conditions being treated, (b) specialties of the prescribers, (c) dose ranges, and (d) the extent of documentation and follow-up. METHODS: A retrospective review of both claims data and patient charts was performed by a clinical pharmacist. Patients were identified from CareOregon and Oregon Medicaid fee-for-service drug claim databases. All patients were recipients of the Oregon Medicaid program known as the Oregon Health Plan (OHP) and were enrolled members of CareOregon, a contracted OHP managed care organization that primarily serves Medicaid recipients. All patients received care at one of four Oregon Health and Science University primary care clinics. RESULTS: Of the 105 patients studied, 95% received gabapentin for off-label diagnoses. Chronic pain and mental disorders were the diagnoses associated with the majority of prescriptions for gabapentin. Dose and dose intervals varied greatly. Very few patients (12%) had a documented efficacious response to gabapentin therapy. Of the patients started on gabapentin, 40% of patients had no documented follow-up. CONCLUSIONS: Almost all patients in this sample from the Medicaid managed population received gabapentin for off-label indications. Evidence from clinical trials does not support the use of gabapentin for many of the conditions treated with gabapentin in this study. Most patients did not appear to benefit from gabapentin therapy.