Role of long-term morphine for central pain appears limited

David Berg · 03-13-2002, 08:34 PM

Found this on Medscape. Small study, but most studies about central pain are small. I wish they offered more specifics about exactly why morphine was discontinued. It shouldn't be too difficult to give more details, especially when you consider how few patients were involved.

David Berg
------------------------------

http://www.medscape.com/viewarticle/...mp=neur-030802

Role of Morphine as Long-Term Treatment for Central Pain Appears Limited

NEW YORK (Reuters Health) Mar 05 - Morphine therapy controls some aspects of central pain syndromes, but only a minority of patients seem to tolerate long-term therapy, according to a report published in the February 26th issue of Neurology.
Dr. Didier Bouhassira, from Hopital Ambroise Pare in Boulogne, France, and colleagues performed a randomized, placebo-controlled study to assess the benefits of morphine in 15 patients with central pain syndromes. Six patients had experienced a prior stroke and nine had spinal cord injuries. After being treated with IV morphine, the patients were started on sustained oral morphine.

Treatment with morphine was associated with a significant improvement in dynamic mechanical allodynia, but had no effect on other evoked pains, the researchers note. Seven patients reported improvements in spontaneous pain with morphine, but, overall, no treatment effect was observed.

The reduction in spontaneous pain that occurred in some patients was directly related to a decrease in heat sensitivity on the nonpainful contralateral side, the investigators state. This finding suggests that the general nociceptive activity of morphine was responsible for the reductions in spontaneous pain.

Only three patients remained on oral morphine for more than 1 year, the authors point out. The emergence of side effects appeared to be a major reason for treatment discontinuation.

"Opioids may represent a therapeutic alternative for central neuropathic pains, but only a small group of patients seem to be able to continue long-term treatment, because of an unfavorable balance between efficacy and side effects," Dr. Bouhassira's team concludes.

Neurology 2002;58:554-563.

calico · 03-14-2002, 07:28 AM

Does "significant improvement in dynamic mechanical allodynia" mean they hurt less when they moved their bodies, or does it mean they had less pain when they were touched, or both?

If 7 patients out of 15 had improvements in spontaneous pain, that seems like a pretty big benefit and I'm not sure I understand the statement that "overall, no treatment effect was observed."

I sure hope they're making some headway in developing drugs to either counteract or not have the side-effects of opioids. It's long overdue.

Calico

David wrote:

Treatment with morphine was associated with a significant improvement in dynamic mechanical allodynia, but had no effect on other evoked pains, the researchers note. Seven patients reported improvements in spontaneous pain with morphine, but, overall, no treatment effect was observed.

David Berg · 03-14-2002, 08:11 PM

calico,

I'll have to admit, sometimes "scholarly" language gets in its own way. AS a layperson, I can read, "significant improvement in dynamic mechanical allodynia," I can see a couple of possible ways to interpret that statement, so your guess is as good as mine.

I'm sure there must be a formal definition for "dynamic mechanical," but it sounds like they're either referring to movement or touch, though I've seen simpler terms for those types of allodynia (which basically means something that's painful that normally wouldn't hurt).

As far as, "overall, no treatment effect was observed," that had me pretty confused, too. It almost sounds like they must be saying that about half of the people were helped, but the treatment went so badly for the others that it balanced out any positive effect. I'm positive that's not what they meant. I'm guessing they must be saying that there was at least some benefit from morphine, but perhaps not enough to really be considered effective.

I wish I had access to the full text of the article in "Neurology," but that's not readily available where I live. According to the citation, it's a 9-page article. I imagine things would be a little clearer if were had more than the "Reader's Digest" version.

David Berg

03-13-2002, 08:34 PM	#1
David Berg Moderator Join Date: Sep 2001 Location: St. Louis, MO Posts: 7,006	Role of long-term morphine for central pain appears limited Found this on Medscape. Small study, but most studies about central pain are small. I wish they offered more specifics about exactly why morphine was discontinued. It shouldn't be too difficult to give more details, especially when you consider how few patients were involved. David Berg ------------------------------ http://www.medscape.com/viewarticle/...mp=neur-030802 Role of Morphine as Long-Term Treatment for Central Pain Appears Limited NEW YORK (Reuters Health) Mar 05 - Morphine therapy controls some aspects of central pain syndromes, but only a minority of patients seem to tolerate long-term therapy, according to a report published in the February 26th issue of Neurology. Dr. Didier Bouhassira, from Hopital Ambroise Pare in Boulogne, France, and colleagues performed a randomized, placebo-controlled study to assess the benefits of morphine in 15 patients with central pain syndromes. Six patients had experienced a prior stroke and nine had spinal cord injuries. After being treated with IV morphine, the patients were started on sustained oral morphine. Treatment with morphine was associated with a significant improvement in dynamic mechanical allodynia, but had no effect on other evoked pains, the researchers note. Seven patients reported improvements in spontaneous pain with morphine, but, overall, no treatment effect was observed. The reduction in spontaneous pain that occurred in some patients was directly related to a decrease in heat sensitivity on the nonpainful contralateral side, the investigators state. This finding suggests that the general nociceptive activity of morphine was responsible for the reductions in spontaneous pain. Only three patients remained on oral morphine for more than 1 year, the authors point out. The emergence of side effects appeared to be a major reason for treatment discontinuation. "Opioids may represent a therapeutic alternative for central neuropathic pains, but only a small group of patients seem to be able to continue long-term treatment, because of an unfavorable balance between efficacy and side effects," Dr. Bouhassira's team concludes. Neurology 2002;58:554-563.

03-14-2002, 07:28 AM	#2
calico Senior Member Join Date: Oct 2001 Posts: 272	To David re: morphine study article Does "significant improvement in dynamic mechanical allodynia" mean they hurt less when they moved their bodies, or does it mean they had less pain when they were touched, or both? If 7 patients out of 15 had improvements in spontaneous pain, that seems like a pretty big benefit and I'm not sure I understand the statement that "overall, no treatment effect was observed." I sure hope they're making some headway in developing drugs to either counteract or not have the side-effects of opioids. It's long overdue. Calico David wrote: Treatment with morphine was associated with a significant improvement in dynamic mechanical allodynia, but had no effect on other evoked pains, the researchers note. Seven patients reported improvements in spontaneous pain with morphine, but, overall, no treatment effect was observed.

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03-14-2002, 08:11 PM	#3
David Berg Moderator Join Date: Sep 2001 Location: St. Louis, MO Posts: 7,006	calico, I'll have to admit, sometimes "scholarly" language gets in its own way. AS a layperson, I can read, "significant improvement in dynamic mechanical allodynia," I can see a couple of possible ways to interpret that statement, so your guess is as good as mine. I'm sure there must be a formal definition for "dynamic mechanical," but it sounds like they're either referring to movement or touch, though I've seen simpler terms for those types of allodynia (which basically means something that's painful that normally wouldn't hurt). As far as, "overall, no treatment effect was observed," that had me pretty confused, too. It almost sounds like they must be saying that about half of the people were helped, but the treatment went so badly for the others that it balanced out any positive effect. I'm positive that's not what they meant. I'm guessing they must be saying that there was at least some benefit from morphine, but perhaps not enough to really be considered effective. I wish I had access to the full text of the article in "Neurology," but that's not readily available where I live. According to the citation, it's a 9-page article. I imagine things would be a little clearer if were had more than the "Reader's Digest" version. David Berg