Morphine responsiveness in a group of well-defined multiple sclerosis patients: a study with i.v. morphine.
Pain in multiple sclerosis (MS) is more common than has previously been believed. About 28% of all MS patients suffer from central pain (CP), a pain that is difficult to treat. In the present study we have investigated the responsiveness of this pain to morphine. Fourteen opioid-free patients (eight woman and six men) with constant, non-fluctuating, long-lasting CP caused by MS were investigated. Placebo (normal saline), morphine and naloxone were given intravenously in a standardized manner. The study design was non-randomized, single blind and placebo controlled. Ten patients experienced less than 50% pain reduction by placebo and less than 50% pain reduction by morphine. Four patients were opioid responders, i.e. had minimal or no effect on pain by placebo, >50% pain reduction after morphine and >25% pain increase after naloxone, given intravenously following morphine. However, this response was obtained after high doses of morphine (43 mg, 47 mg, 50 mg and 25 mg; mean 41 mg). Thus, compared with nociceptive pain, only a minority of the patients with CP due to MS responded to morphine and only at high doses. The present results are in accord with experimental studies indicating that neuropathic pain is poorly responsive but not totally unresponsive to opioids. The results do not support the routine use of strong opioids in MS patients with CP.
Kalman
Sigga
S
Department of Anaesthesiology, University Hospital, S-581 85 Linköping, Sweden.
Osterberg
Anders
A
Sörensen
Jan
J
Boivie
Jörgen
J
Bertler
Ake
A
D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D002490:Central Nervous System / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D018849:Controlled Clinical Trials as Topic; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D009103:Multiple Sclerosis / Q000150:complications*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects; D010148:Intractable Pain / Q000188:drug therapy* / Q000209:etiology* / Q000503:physiopathology; D016037:Single-Blind Method; D012894:Sleep Stages / Q000187:drug effects / Q000502:physiology; D011795:Surveys and Questionnaires; D017211:Treatment Failure
D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D009270:Naloxone; D009020:Morphine