Lidocaine patch: double-blind controlled study of a new treatment method for post-herpetic neuralgia.
Post-herpetic neuralgia (PHN) is a common and often intractable neuropathic pain syndrome predominantly affecting the elderly. Topical local anesthetics have shown promise in both uncontrolled and controlled studies. Thirty-five subjects with established PHN affecting the torso or extremities completed a four-session, random order, double-blind, vehicle-controlled study of the analgesic effects of topically applied 5% lidocaine in the form of a non-woven polyethylene adhesive patch. All subjects had allodynia on examination. Up to 3 patches, covering a maximum of 420 cm2, were applied to cover the area of greatest pain as fully as possible. Lidocaine containing patches were applied in two of the four 12-h-long sessions, in one session vehicle patches were applied, and one session was a no-treatment observation session. Lidocaine containing patches significantly reduced pain intensity at all time points 30 min to 12 h compared to no-treatment observation, and at all time points 4--12 h compared to vehicle patches. Lidocaine patches were superior to both no-treatment observation and vehicle patches in averaged category pain relief scores. The highest blood lidocaine level measured was 0.1 micrograms/ml, indicating minimal systemic absorption of lidocaine. Patch application was without systemic side effect and well tolerated when applied on allodynic skin for 12 h. This study demonstrates that topical 5% lidocaine in patch form is easy to use and relieves post-herpetic neuralgia.
Rowbotham
Michael C
MC
Departments of Neurology and Anesthesia, UCSF Pain Clinical Research Center, University of California, San Francisco, CA 94115 USA.
Davies
Pamela S
PS
Verkempinck
Christina
C
Galer
Bradley S
BS
D000279:Administration, Cutaneous; D000368:Aged; D000369:Aged, 80 and over; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000097:blood / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006562:Herpes Zoster / Q000150:complications*; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage* / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000188:drug therapy* / Q000209:etiology; D010147:Pain Measurement; D014677:Pharmaceutical Vehicles
D000779:Anesthetics, Local; D014677:Pharmaceutical Vehicles; D008012:Lidocaine