Lidocaine eye drops attenuate pain associated with ophthalmic postherpetic neuralgia.

Author(s): Kanai A, Okamoto T, Suzuki K, Niki Y, Okamoto H

Affiliation(s): Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, Japan. kanaiakifumi@aol.com

Publication date & source: 2010-05-01, Anesth Analg., 110(5):1457-60. Epub 2010 Mar 17.

Publication type: Randomized Controlled Trial

BACKGROUND: Topical lidocaine (LDC) treatment using a gel or patch preparation is effective in the treatment of postherpetic neuralgia (PHN), but neither is suited for the eye in patients with ophthalmic PHN. Herein, we examined the effect of LDC 4% eye drops on ophthalmic PHN pain. METHODS: Twenty-four patients with ophthalmic PHN were randomized to receive 0.4 mL eye drops of either LDC 4% or saline placebo (PBO) in the painful eye. After a 7-day period, the patients were crossed over to receive the alternative eye drops. The pain in the eye and the forehead was assessed with a visual analog scale (VAS) before and 15 minutes after treatment. Patients used a descriptive scale to grade pain outcome and were asked to note whether the pain returned and how long after therapy it recurred. RESULTS: LDC significantly decreased the VAS score of persistent pain in the eye (baseline: 5.9 +/- 2.2 cm; 15 minutes after eye drops: 0.9 +/- 1.8 cm, mean +/- SD [P < 0.01]) and in the forehead (baseline: 6.3 +/- 2.0 cm; 15 minutes after eye drops: 2.6 +/- 2.7 cm [P < 0.01]). The delta change in these VAS scores between LDC and PBO was significant (P < 0.01). Moreover, pain was described as moderate or better by 23 patients after they received LDC and 4 patients of the PBO group. The effect of LDC persisted for a median of 36 hours (range, 8-96 hours) after application. CONCLUSIONS: This study suggests that LDC provides a significant improvement of ophthalmic PHN because of its prompt analgesia, lack of systemic side effects, and convenience of use.