Methadone may promote HIV replication: Study

Results obtained in vitro, so conclusions are limited

Investigators at the University of Pennsylvania School of Medicine in Philadelphia have found that HIV replication is promoted in vitro by the opiate methadone.1 Although this research is a long way from concluding that injection-drug-using HIV patients should avoid methadone treatment, it does raise questions that will need to be answered through further studies.

"We don’t want anyone to say, Gee, I stopped my morphine and substance abuse and now will not take methadone because it will do something terrible to me,’" says Steven D. Douglas, MD, chief of the section of immunology at Children’s Hospital of Philadelphia and professor of pediatrics at the University of Pennsylvania Medical School in Philadelphia.

Yuan Li, MD, and Wenzhe Ho, MD, presented an abstract on the study at the international conference of the PsychoNeuroImmunology Research Society, held in May 2001 in Utrecht, The Netherlands. However, the research clearly shows that the HIV strains tested with methadone had increased reverse transcriptases and increased expression of CCR5 receptors on the cell membrane, which may be a method for HIV to enter immune cells, Douglas says. "The methadone effect is limited to CCR5 strains," Douglas says. Investigators had hypothesized that methadone would have a negative effect on HIV infection because of its immunosuppressive effects on human immune cells, Douglas says.

The study also suggests that methadone could change latent HIV infection to active HIV replication in cell cultures through the activation of HIV LTR, a promoter. "These are findings we should think about, but this is not a study to draw clinical inferences from or to base clinical recommendations on," he notes.

The study abstract says the findings suggest that HIV-1-infected patients who are receiving methadone as treatment for dependence on morphine or heroin should be observed for changes in their viral load, development of viral resistance, and other possible adverse consequences.