Topical amitriptyline versus lidocaine in the treatment of neuropathic pain.
OBJECTIVE
Oral amitriptyline, a tricyclic antidepressant, is effective for treating neuropathic pain. We conducted a double-blind, randomized, placebo-controlled crossover study to evaluate the efficacy of topical 5% amitriptyline and 5% lidocaine in treating patients with neuropathic pain.


METHODS
Thirty-five patients with postsurgical neuropathic pain, postherpetic neuralgia, or diabetic neuropathy with allodynia or hyperalgesia were assigned to receive 3 topical creams (5% amitriptyline, 5% lidocaine, or placebo) in random sequence. The primary outcome measure was change in pain intensity (baseline vs. posttreatment average pain) using a 0 to 100 mm Visual Analog Scale. Secondary outcome measures included the McGill Pain Questionnaire, requirement for rescue medication, and patient satisfaction. Primary statistical comparisons were made with paired t tests or signed-rank tests.


RESULTS
A reduction in pain intensity was observed with topical lidocaine (P<0.05). No significant change in pain intensity was found with topical amitriptyline or placebo. In pairwise comparison of treatments, topical lidocaine and placebo each reduced pain more than topical amitriptyline (P<0.05).


CONCLUSIONS
This randomized, placebo-controlled crossover study examining topical 5% amitriptyline and 5% lidocaine in the treatment of neuropathic pain showed that topical lidocaine reduced pain intensity but the clinical improvement is minimal and that topical 5% amitriptyline was not effective.
Ho
Kok-Yuen
KY
Department of Anaesthesia and Surgical Intensive Care, Singapore General Hospital, Singapore. hokokyuen@yahoo.com.sg
Huh
Billy K
BK
White
William D
WD
Yeh
Chun-Chang
CC
Miller
Eric J
EJ
D000287:Administration, Topical; D000639:Amitriptyline / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy* / Q000209:etiology*; D010147:Pain Measurement; D010523:Peripheral Nervous System Diseases / Q000150:complications*; D011446:Prospective Studies; D018401:Sample Size; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D018712:Analgesics, Non-Narcotic; D000779:Anesthetics, Local; D000639:Amitriptyline; D008012:Lidocaine