Secondary Opioid Use in Postherpetic Neuralgia Suggests Suboptimal Gabapentin, Pregabalin Titration

HONOLULU, HI—The percentage of patients in community-practice settings who newly initiate opioid therapy while taking gabapentin and pregabalin for postherpetic neuralgia suggest these agents should be titrated to higher and potentially more effective dosages, a study presented at the American Pain Society’s 31st Annual Scientific Meeting has found.

Michael Sweeney, MD, of OptumInsight, Eden Prairie, MN, and colleagues used administrative claims data from a large U.S. health plan to identify commercial and Medicare Advantage enrollees with postherpetic neuralgia who initiated treatment with gabapentin or pregabalin from January 2006 to February 2009. The index date was the date of the first pharmacy claim for gabapentin or pregabalin.

Patients were required to have ≥6 months of data preceding and ≥12 months following the index date, and to have evidence of postherpetic neuralgia (ICD-9-CM code 053.1x) on or ≤2 days following it. During the 12-month follow-up period, mean daily dosages, time to reach maximum dosage, number of prescription fills, presence of >1 fill with optimal/effective dosage, and added and switched therapies were examined. They identified 1,645 patients, 939 taking gabapentin and 706 on pregabalin. Mean age was 63 years; 41% were male, and 22% were enrolled in Medicare Advantage.

Mean (SD) daily dosage of gabapentin was 826mg (559mg) and pregabalin, 187mg (103mg), both below U.S. Food and Drug Administration-approved maximum dosages. New prescriptions for opioids (ie, none in the pre-index period) were given to 57% of patients taking gabapentin and 58% of patients taking pregabalin.

“A significantly greater percentage of patients taking gabapentin received a new prescription for oxycodone than did subjects taking pregabalin (17% vs. 11.5%),” the investigators found. “It is possible that if patients in community practice were titrated to higher and potentially more effective dosages of gabapentin or pregabalin, use of opioid analgesics in postherpetic neuralgia might be reduced. These data suggest there remains an unmet need in the treatment of PHN.”