A gastroretentive gabapentin formulation for the treatment of painful diabetic peripheral neuropathy: efficacy and tolerability in a double-blind, randomized, controlled clinical trial.

AIMS: A randomized, double-blind, placebo-controlled study was conducted in 147 patients to determine the efficacy and safety of a gastroretentive formulation of gabapentin (G-GR) in treating painful diabetic peripheral neuropathy (DPN).

METHODS

Diabetic patients with symmetrical painful symptoms in distal extremities for 1-5 years and a baseline average daily pain (ADP) score of ≥4 received G-GR 3000mg, as a single evening daily dose (G-GR-QD) or a divided dose (G-GR-DD, 1200mg AM/1800mg PM), or placebo for 4 weeks. G-GR was titrated from 300 to 3000mg/day over 2 weeks, followed by 2 additional weeks at 3000mg/day. Efficacy measures included changes from baseline to Week 4 in ADP score and average daily sleep interference score (SIS).

RESULTS

A significantly larger decrease in ADP score was observed in the G-GR-QD dose group compared with placebo (-2.50 versus -1.30; p=0.002). A ≥50% reduction in ADP score was achieved in 34.8% of G-GR-QD recipients compared with 7.8% of placebo recipients (p=0.001). Similar results were observed for changes in SIS. The incidences of dizziness and somnolence, commonly associated with gabapentin, were low.

CONCLUSIONS

Once-daily G-GR was effective and well tolerated for the treatment of pain due to DPN.