Post-herpetic neuralgia: 5% lidocaine medicated plaster, pregabalin, or a combination of both? A randomized, open, clinical effectiveness study.

OBJECTIVE: To compare efficacy and safety of 5% lidocaine medicated plaster with pregabalin in patients with post-herpetic neuralgia (PHN), and to assess the benefits of combining both drugs in patients not responding to either single agent.

STUDY DESIGN AND METHODS: This was a two-stage adaptive, randomised, open-label, multicentre, non-inferiority study (NCT 00414349). The subset of patients with PHN is reported here. Patients with an absolute value of >4 on the NRS-3 were randomly assigned to 4-week treatment with 5% lidocaine medicated plaster or twice-daily pregabalin capsules titrated to effect. Subsequently, patients sufficiently treated with monotherapy (patients with NRS-3 or=2 points) continued with monotherapy; patients insufficiently treated with monotherapy received both drugs in combination for 8 weeks.

OUTCOME MEASURES: Pain according to SF-MPQ and NPSI, onset of effect, reduction in worst pain on the NRS; allodynia severity; quality of life (QoL) based on EQ-5D, SF-36; PGIC; rescue medication intake; adverse events (AEs) monitoring.

RESULTS: At 4 weeks, SF-MPQ total scores improved by -7.6 +/- 6.66 (mean +/- SD) under 5% lidocaine medicated plaster and by -5.3 +/- 7.93 under pregabalin. NPSI total scores declined by -1.6 +/- 1.73 under 5% lidocaine medicated plaster and -1.4 +/- 1.87 under pregabalin. Lidocaine plaster was also effective in reducing worst pain and showed a fast onset of effect. During combination treatment, SF-MPQ and NPSI scores, allodynia, EQ-5D and PGIC improved. Incidences of AEs were in line with previous reports for the two treatments and combination therapy was generally well-tolerated.

CONCLUSIONS: Although this open-label study is lacking a placebo control group, the results suggest that 5% lidocaine medicated plaster is at least as effective as pregabalin for pain relief in PHN, with a favourable safety profile and a resulting positive benefit-risk ratio. In patients unresponsive to either monotherapy, combination therapy provides additional efficacy and is well-tolerated.