Opioids May Have New Use
Study finds drugs may help treat pain that can follow shingles
TUESDAY, Oct. 8, 2002 (HealthDayNews) -- Opioids may help treat people with post-herpetic neuralgia (PHN), a painful chronic condition that can develop after a case of shingles.
That's the claim of a study in today's issue of Neurology.
Researchers from Johns Hopkins University and the U.S. National Institutes of Health showed that opioids are highly effective in reducing pain in people with PHN and they don't affect cognitive function.
PHN causes ongoing pain with varying degrees of skin hypersensitivity. Common treatments include the lidocaine patch, anti-epileptic drugs and oral tricyclic antidepressants (TCAs).
This study compared results using TCAs, opioids and a placebo to treat 76 people with PHN. Forty four of the people in the study completed all three cycles of treatment. Each treatment lasted about eight weeks. The treatments were separated by one week with no treatment.
The primary opioid used was controlled-release morphine, with methadone used as the alternate in cases where people couldn't tolerate morphine. The primary TCA was nortriptyline, with desipramine as the alternate.
The mean percent pain relief ratings were similar with the opioids and the TCAs, although there tended to be greater pain reductions with the opioids, the study found.
The study also compared effects on cognitive function. Opioids didn't influence cognitive function on any measure, while TCAs slightly worsened cognitive performance on several tests.
"The study provides further convincing evidence that opioids are effective in treating the pain in PHN patients and that opioids can provide a useful alternative treatment for neuropathic pain," says study author Dr. Srinivasa Raja, Johns Hopkins University School of Medicine.
However, Raja says it's premature to argue that opioids should be the treatment of first choice for PHN or neuropathic pain in general, and he recommends more long-term studies.
There's more about opioids at Johns Hopkins University.