WASHINGTON – Increased doses of methadone may be good for opioid dependence, but they might not be good for a patient's sex life.
“Although it hasn't been well studied in [methadone patients], we know that sexual dysfunction as a side effect can interfere with compliance in a clinical setting,” Randall Brown, M.D., said at the annual conference of the Association for Medical Education and Research in Substance Abuse.
Methadone is among the most popular treatments for opioid dependence; it has been shown to reduce opiate use and mortality, and psychosocial outcomes for patients include lower crime rates and improved employment status.
Side effects from methadone use include weight gain, insomnia, and constipation, but sexual dysfunction could be a “deal breaker” for some patients.
Between 30% and 100% of methadone patients report sexual dysfunction problems, with men mostly reporting problems with libido and maintaining erections, said Dr. Brown, who conducted a cross-sectional study as part of a primary care fellowship at the University of Wisconsin.
Dr. Brown's work was funded in part by an NIH research grant. To assess whether the likelihood and severity of sexual dysfunction increased with higher doses, he compared 16 new patients who started methadone as therapy for opioid addiction with 76 men who had been involved in methadone maintenance for at least 60 days.
Overall, 14% of the men across both groups reported some sexual dysfunction, which is similar to male sexual dysfunction rates in the general population. A dose increase was significantly associated with orgasm dysfunction, before and after adjusting for the duration of methadone treatment.
However, no significant increase in dysfunction was associated with either serum testosterone or serum prolactin levels.
There was a significant association between TSH and duration of treatment, but levels remained within the normal range.
Sexual function was evaluated with a 28-question form using rating scales from 1 to 100 for libido, erectile dysfunction, and orgasm dysfunction, and with patient interviews about medical history and ongoing use of alcohol or other drugs.
“We didn't find the alterations in testosterone [with methadone dosage] that we expected,” Dr. Brown said.
In the 1970s, several studies measured testosterone levels of methadone patients without relating it to dosage, he noted at the conference, also sponsored by Brown Medical School.
Some studies showed a drop in testosterone associated with dosage greater than 60 mg, but other studies failed to show any difference.
“Sexual dysfunction in men on methadone maintenance should be evaluated in accordance with guidelines established for the general population,” he said.
However, if orgasm dysfunction negatively affects a patient's quality of life to the extent that he considers discontinuing the methadone, a trial short-term dose reduction may be helpful.