Opioids like morphine are often used for pain relief in cancer patients. They are known to cause severe constipation that often cannot be relieved by traditional laxatives. Methylnaltrexone, is a drug that is given to late-stage cancer patients to help ease the constipation brought on by morphine. Researchers have suggested that methylnaltrexone could play a role in cancer therapy as it has been shown to extend the patients' lives.
Jonathan Moss, lead author of the study and professor of anesthesia and critical care at the University of Chicago, said, "Early on, we began to suspect that methylnaltrexone might inhibit cancer growth. After more than a decade in the lab trying to assess how methylnaltrexone affects cancer, we have the first evidence that it can decrease tumor growth and extend survival in patients who respond to the drug."
For the study, researchers analyzed 229 patients across two randomized, controlled clinical trials on the relief of constipation for patients in the late stages of cancer and other terminal diseases. The study said, "In these two trials, 117 cancer patients received methylnaltrexone (marketed as Relistor) for opioid-induced constipation, while 112 were given a placebo."
Methylnaltrexone did not have any life-extending effects on patients with other illnesses like congestive heart failure, advanced chronic obstructive pulmonary disease or neurologic diseases. The research team is not sure exactly how the drug works to extend life, and are continuing to study the matter.
The findings were presented at the meeting of the American Society of Anesthesiologists in San Diego.