The Use of Opioids in Patients with Postherpetic Neuralgia (PHN) Treated with Gabapentin (P04.169)

Abstract

Objective: To examine opioid use following prescription of gabapentin for treatment of PHN in community-practice settings. Background Gabapentin is recommended as first-line treatment for postherpetic neuralgia (PHN) by the AAN. It is usually taken 3-4 times per day and must be titrated to an effective dosage over several weeks. For patients who have insufficient pain relief or poor tolerability, opioids are often used as second-line therapy. Which opioids and frequency of use have not been studied to date for patients with PHN. Design/Methods: Administrative claims data from a large U.S. health plan were used to identify commercial and Medicare Advantage enrollees with PHN who initiated treatment with gabapentin from January 2006-February 2009. The first gabapentin pharmacy claim date was designated the index date. Patients were required to have ≥6 months of data preceding and ≥12 months following the index date and to have evidence of PHN (ICD-9-CM code 053.1x) on or ≤2 days following it. Mean daily dose, and added and switched therapies, were examined during the 12-month follow-up period. Results: A total of 939 patients (mean age 63.8 years, males 39%, Medicare Advantage 26%) met all inclusion criteria. The mean (SD) daily dosage of gabapentin during the follow-up period was 826 (559) mg, much lower than the approved 1800 mg dosage. 37% of patients added another therapy after initiating gabapentin (57% added opioids), and 58% switched to another therapy (35% to opioids). The most common opioids used were hydrocodone (26% added, 9% switched), oxycodone (13%/3%), tramadol (5%/2%), propoxyphene (4%/2%), and fentanyl (3%/3%). Conclusions: Many patients with PHN on gabapentin appeared to remain well below the approved efficacious dosage. Patients were frequently switched to strong opioids, with oxycodone and hydrocodone being the predominant therapies used. If more patients reached efficacious dosages of gabapentin, opioid use in PHN might be reduced. Supported by: Depomed, Inc. Disclosure: Dr. Johnson has nothing to disclose. Dr. Halpern has nothing to disclose. Dr. Becker has nothing to disclose. Dr. Sweeney has received personal compensation for activities with Depomed, Inc., as an employee. Dr. Dworkin has received personal compensation for activities with Acura, Analgesic Solutions, Astellas, Cypress, Dainippon Sumitomo, Depomed, DePuy, Durect, Endo, Epicept, Flexion, Forest, Grumnenthal, Infinity, Jazz, King, Lilly, McNeil, Merck, NeurogesX, Ono, Sanofi Aventis, Seikagaku, Sepracor, Smith & Nephew, Spinifex, US Department of Veterans Affairs, US National Institutes of Health, Wyeth, and Xenon as a consultant.Dr. Dworkin has received research support from Arcion, Montel Williams Foundation, Philips Respironics, Serono, and US Food and Drug Administration.