Dextromethorphan mitigates phantom pain in cancer amputees.

Abstract

BACKGROUND:

Hyperexcitability of N-methyl-D-aspartate (NMDA) receptors may play a role in the persistence of phantom pain. Dextromethorphan (DM) blocks NMDA receptors.

METHODS:

Eight cancer and two noncancer amputees with established, disabling phantom pain received oral DM 60 or 90 mg twice daily (BID) in a three-period double-blind crossover placebo-controlled trial. This followed an open-phase trial in which either dose was given three times daily if pain relief during the double-blind phase was <50% of pretreatment intensity. Patients then underwent a 3-month phase of treatment with the best regimen and a subsequent 1-month posttreatment follow-up.

RESULTS:

All patients reported a >50% decrease in pain intensity, better mood, and lower sedation in each treatment phase. Four individuals reported this level of pain relief with the 60-mg and one with the 90-mg BID regimen during the double-blind phase, whereas two amputees benefited from the 60-mg and three from the 90-mg thrice-daily regimen in the open-phase trial. One reported exacerbation of pain with the 90-mg BID regimen, and three reported pain rebound at the 1-month posttreatment follow-up phase. Three patients stopped all previous analgesic use during the study.

CONCLUSIONS:

Persistent phantom pain probably involves NMDA receptor hyperexcitability because DM 120 to 270 mg/day mitigated the pain satisfactorily.

• Authors: Ron Ben Abraham, Nissim Marouani, Avi A Weinbroum
• Journal: Annals of surgical oncology (Ann Surg Oncol) Vol. 10 Issue 3 Pg. 268-74 (Apr 2003) ISSN: 1068-9265 [Print] United States
• PMID: 12679312 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial)

Chemical References

• Excitatory Amino Acid Antagonists
• Receptors, N-Methyl-D-Aspartate

Topics

• Administration, Oral
• Adult
• Affect
• Aged
• Amputation, Surgical
• Cross-Over Studies
• Double-Blind Method
• Excitatory Amino Acid Antagonists (pharmacology)
• Female
• Humans
• Male
• Middle Aged
• Neoplasms (surgery)
• Pain (drug therapy)
• Phantom Limb (drug therapy, etiology)
• Quality of Life
• Receptors, N-Methyl-D-Aspartate (drug effects, physiology)