LAS VEGAS, NV—When used in combination with the calcium channel alpha2-delta ligands pregabalin and gabapentin, lidocaine 5% patch is well tolerated and safe for postherpetic neuralgia (PHN), according to a post-hoc analysis of pooled study data presented at PAINWeek 2012.
The lidocaine 5% patch, pregabalin, and gabapentin are all indicated in postherpetic neuralgia. According to guidelines, they are recommended as individual therapies. Small scale studies conducted in patients failing to achieve relief with monotherapy have shown a synergistic effect between the lidocaine 5% patch and one of the alpha2-delta ligands when used concomitantly.
Matthew Wieman, MD, from Endo Pharmaceuticals Inc, Chadds Ford, PA, and colleagues conducted a post-hoc analysis of pooled data from two studies to assess the safety of lidocaine patch 5% in combination with calcium channel alpha2-delta ligands as treatment for postherpetic neuralgia.
The first study, conducted in a total of 107 (baseline PHN n=11) patients, was a nonrandomized, open-label, multicenter study in which patients with PHN who had a partial response to monotherapy with gabapentin (pain >4 on a scale of 0–10) added the 5% lidocaine patch to their regimen (≤4 patches every 24 hours) for 2 weeks. Nine out of the 11 patients reported improvement in pain relief at 2 weeks compared with baseline.
The second study, conducted in a total of 300 patients (baseline PHN n=35), was a Phase 3, randomized, open-label, multicenter, noninferiority study in which patients with PHN and an insufficient response to either monotherapy with the lidocaine 5% patch or pregabalin (pain >4 on a scale of 0–10) were administered the lidocaine 5% patch plus pregabalin for 8 weeks. Patients treated with combination lidocaine patch 5% and pregabalin exhibited a reduction in -3 average pain intensity at Week 8 compared to Baseline.
Overall, no serious adverse events took place with either trial. For the treatment of PHN, Dr. Wieman and colleagues concluded that combination therapy with the lidocaine 5% patch and a calcium channel alpha2-delta ligand is generally well tolerated for up to 8 weeks (in combination with pregabalin) or 2 weeks (in combination with gabapentin).