Efficacy and safety of pregabalin 600 mg/d for treating painful diabetic peripheral neuropathy: A double-blind placebo-controlled trial

BACKGROUND: Recent consensus guidelines recommend pregabalin as a first-tier treatment for painful diabetic peripheral neuropathy (DPN). We evaluated the efficacy of pregabalin 600 mg/d (300 mg dosed BID) versus placebo for relieving DPN-associated neuropathic pain, and assessed its safety using objective measures of nerve conduction (NC). METHODS: In this randomized, double-blind, placebo-controlled trial, the primary efficacy measure was endpoint mean pain score (MPS) from daily pain diaries (11-point scale). NC velocity and sensory and motor amplitudes were assessed at baseline, endpoint, and end of follow-up (2 weeks post-treatment). At each timepoint, the median-motor, median-sensory, ulnar-sensory, and peroneal-motor nerves were evaluated. Secondary efficacy measures included weekly MPS and proportion of responders (patients achieving ≥50% reduction in MPS from baseline to endpoint). After 1-weeks' dosage escalation, pregabalin-treated patients received 300 mg BID for 12 weeks. RESULTS: Eighty-two patients received pregabalin and 85 placebo. Mean durations were 10 years for diabetes and ~5 years for painful DPN. Pregabalin-treated patients had lower MPS than controls (mean difference, -1.28; p <.001). For all four nerves, 95% CIs for median differences in amplitude and velocity from baseline to endpoint and baseline to follow-up included 0 (ie, no significant difference vs. placebo). Significant pain improvement among pregabalin-treated patients was evident at week 1 and sustained at every weekly timepoint. More pregabalin-treated patients (49%) than controls (23%) were responders (p <.001). CONCLUSION: Pregabalin 600 mg/d (300 mg BID) effectively reduced pain, was well tolerated, and had no statistically significant or clinically meaningful effect on NC in patients with painful DPN. TRIAL REGISTRATION: ClinicalTrials.gov NCT00159679