Topical application of doxepin hydrochloride, capsaicin and a combination of both produces analgesia in chronic human neuropathic pain: a randomized, double-blind, placebo-controlled study.

Abstract

AIMS:

To assess the analgesic efficacy of topical administration of 3.3% doxepin hydrochloride, 0.025% capsaicin and a combination of 3. 3% doxepin and 0.025% capsaicin in human chronic neuropathic pain.

METHODS:

A randomized, double-blind, placebo-controlled study of 200 consenting adult patients. Patients applied placebo, doxepin, capsaicin or doxepin/capsaicin cream daily for 4 weeks. Patients recorded on a daily basis overall pain, shooting, burning, paraesthesia and numbness using a 0-10 visual analogue scale during the week prior to cream application (baseline levels) and for the 4 week study period. Side-effects and desire to continue treatment were also recorded.

RESULTS:

Overall pain was significantly reduced by doxepin, capsaicin and doxepin/capsaicin to a similar extent. The analgesia with doxepin/capsaicin was of more rapid onset. Capsaicin significantly reduced sensitivity and shooting pain. Burning pain was increased by doxepin and by capsaicin and to a lesser extent by doxepin/capsaicin. Side-effects were minor. One patient requested to continue placebo cream, 17 doxepin cream, 13 capsaicin and 9 the combination of doxepin and capsaicin.

CONCLUSIONS:

Topical application of 3.3% doxepin, 0.025% capsaicin and 3.3% doxepin/0. 025% capsaicin produces analgesia of similar magnitude. The combination produces more rapid analgesia.

• Authors: G McCleane
• Journal: British journal of clinical pharmacology (Br J Clin Pharmacol) Vol. 49 Issue 6 Pg. 574-9 (Jun 2000) ISSN: 0306-5251 [Print] England
• PMID: 10848721 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial)

Chemical References

• Antidepressive Agents, Tricyclic
• Doxepin
• Capsaicin

Topics

• Administration, Topical
• Adult
• Antidepressive Agents, Tricyclic (administration & dosage, adverse effects, therapeutic use)
• Capsaicin (administration & dosage, adverse effects, therapeutic use)
• Chronic Disease
• Double-Blind Method
• Doxepin (administration & dosage, adverse effects, therapeutic use)
• Female
• Humans
• Male
• Middle Aged
• Pain (drug therapy, etiology, psychology)
• Pain Measurement
• Paresthesia (drug therapy)
• Peripheral Nervous System Diseases (complications)