Treatment of postherpetic neuralgia with 5% lidocaine medicated plaster in elderly patients - subgroup analyses from three European clinical trials.

OBJECTIVE

To investigate short- and long-term effectiveness and safety of the 5% lidocaine medicated plaster in the treatment of postherpetic neuralgia (PHN) in elderly patients (≥70 years of age).

METHODS

Data from three European clinical trials was compared after stratification according to age (<70 years and ≥70 years). Length of study phase investigated was 4 weeks for study 1, 8 weeks for study 2, and up to 12 months for study 3. Effectiveness outcome measures were pain intensity, pain relief, allodynia severity, Clinical Global Impression of Change, and Patient Global Impression of Change. Safety was assessed by adverse event documentation.

RESULTS

Mean average pain intensity improved in the elderly by -2.1 (SD 2.1) vs. -2.5 (SD 2.0) for <70 year old patients after 4 weeks, by -1.4 (SD 1.8) vs. -1.7 (SD 1.3) after 8 weeks, and by -1.5 (SD 1.9) vs. -2.7 (SD 2.2) after 12 months. Most patients presented with allodynia (>85% of elderly, >78% of younger patients) which was described by >51% as painful or extremely painful. Allodynia severity was markedly reduced in both groups during all three trials. Drug-related adverse events occurred in <20% of elderly and <15% of <70 year old patients and were mainly skin related.

CONCLUSIONS

The 5% lidocaine medicated plaster provided pain relief and marked reductions in allodynia severity in elderly PHN patients with an excellent safety profile under short- and long-term treatment supporting the addition of the plaster to the treatment armamentarium for this age group.

STUDY LIMITATIONS

All analyzed study phases were open-label and lacking a placebo control group.