Anesthesia & Analgesia, Vol 86, 579-583, Copyright © 1998 by International Anesthesia Research Society
Treatment of intractable pain with topical large-dose capsaicin: preliminary report
WR Robbins, PS Staats, J Levine, HL Fields, RW Allen, JN Campbell and M Pappagallo
Department of Anesthesia, University of California-San Francisco, 94143, USA.
Complex regional pain syndromes (CRPS) and neuropathic pain are often
poorly controlled by conventional pharmacologic interventions. We
administered 8-methyl-N-vanillyl-noneamide (capsaicin) at doses of 5%- 10%
to individuals with such disorders in this trial. Previous limitations to
trials with larger-dose, topical concentrations of capsaicin included
intense burning sensations experienced after application. To enable
patients to tolerate the high concentrations, we first performed regional
anesthesia. All patients reported at least some relief. Of 10 patients, 9
obtained substantial analgesia that lasted 1-18 wk. At Week 1 after
therapy, the mean verbal analog scale (VAS) scores decreased from 8.0 to
3.0. At Week 4 after therapy, mean VAS score was 4.5. Analgesia lasted from
< 1 wk (1 patient) to more than 50 wk (1 patient). Patients received one
to eight treatments. With one exception, patients receiving more than one
treatment obtained additional relief with subsequent treatment. Pain
responsive to opioids was the only side effect of treatment. Large-dose
capsaicin administered with regional anesthesia may effectively minimize
refractory CRPS and neuropathic pain. A double-blind, placebo- controlled
study in patients with bilateral peripheral neuropathy using epidural
anesthesia with and without large-dose topical capsaicin is in progress.
IMPLICATIONS: Sensory neuropathies are associated with many diseases. Pain
from these disorders can produce greater disability than the primary
disease processes themselves. Currently available therapies are limited.
However, the intermittent application of large-dose topical capsaicin may
provide significant pain relief, decrease chronic analgesic dependence, and
decrease aggregate health care expenditures.