Objective. To assess the effectiveness of the lidocaine patch 5% (Lidoderm®), a targeted peripheral analgesic, in reducing pain intensity/interference with quality of life (QOL) among patients with postherpetic neuralgia (PHN).
Design. Open-label, nonrandomized, effectiveness study; up to three patches applied to area of greatest pain for 12 hours per day for 28 days.
Setting. Forty-two centers consisting of large institutional primary care programs and academic centers, including pain centers, neurologists, and pain specialists affiliated with a university.
Patients. Patients with PHN (N = 332).
Outcome Measures. Patients completed the Brief Pain Inventory Short Form and global pain assessments at baseline, Days 7 and 14, and study conclusion. Physicians completed global assessments at baseline and study conclusion.
Results. The mean time from onset of herpes zoster to treatment was 28 months. Use of the lidocaine patch 5% was associated with reductions in all mean pain intensity, pain interference with QOL, and composite scores at all time points (P = 0.0001). Overall, 66% of patients reported improvement in pain intensity, and 74% reported improved QOL by Day 7; approximately 43% who did not respond by Day 7 experienced improvement in pain intensity by Day 14. For all measures of pain intensity, relief, and interference with QOL, improvements from baseline were equally significant regardless of time since shingles onset. In all, approximately 60% of patients reported moderate to complete pain relief at final evaluation. The lidocaine patch 5% was well tolerated.
Conclusions. Based on results of previous randomized, controlled trials and the current study, designed to gauge response in the clinical practice setting, the lidocaine patch 5% should be considered a first-line therapy, alone or in combination with other agents, for PHN due to its efficacy, safety, minimal systemic side effects and drug interactions, and ease of administration. Although the lidocaine patch 5% was equally effective in longstanding PHN, it would appear prudent to begin therapy as early in the course of PHN as possible.