PALM SPRINGS, CA — In patients with postherpetic neuralgia (PHN), a once-daily formulation of gabapentin 1,800mg was found to be well tolerated and improved all dimensions of pain on the Neuropathic Pain Scale (NPS), according to results of a study presented at the 2012 American Academy of Pain Medicine Annual Meeting.

“A once-daily formulation of gabapentin (G-QD) has been developed using extended-release oral gastroretentive delivery technology to overcome the absorption limits of gabapentin,” noted Misha M. Backonja, MD, of LifeTree Research, Salt Lake City, UT, and colleagues.

The effect of G-QD on pain characteristics was investigated using the 10-item NPS scale in two Phase 3, 11-week, randomized, double-blind, placebo-controlled studies. Following one week of baseline observation, 669 patients with PHN were randomized and titrated over two weeks to G-QD 1,800mg or matched placebo (taken with the evening meal), followed by eight weeks of stable doses. Mean age was 66.1 years; 42.6% were male. The NPS was administered at baseline and at Week 10.

The last observation carried forward change in NPS average score from baseline (5.6) to Week 10 was -2.5 for G-QD vs. -1.9 for placebo (P=0.001). Similar changes were seen in nonallodynia items (-2.4 vs. -1.8; P=0.002) and in the four peripheral pain items (-2.6 vs. -1.9; P=0.001). G-QD was generally well tolerated. The most common adverse events (AEs) for G-QD vs. placebo were dizziness (10.9% vs. 2.2%) and somnolence (4.5% vs. 2.7%). A total of 35 patients (9.7%) in the G-QD 1,800mg group and 25 patients (6.9%) in the placebo group withdrew from the study due to AEs.