Relistor For Opioid-Induced Constipation Approved By The FDA

Relistor (methylnaltrexone bromide), which helps restore bowel function in patients who are in the late stages of advanced illness and receive opioids continuously for pain relief, has been approved by the Food and Drug Administration (FDA).

Opioids are commonly given continuously to patients with late-stage advanced illness for pain relief. This includes people with terminal cancer, end-stage COPD (Chronic Obstructive Pulmonary Disease) from emphysema, heart failure, Alzheimer’s disease with dementia, HIV/AIDS, and some others.

Opioids often relax the intestinal smooth muscles to such an extent that they do not contract and push waste products out. Relistor, by blocking opioid entrance into the cells, allows the bowels to continue working properly.

Joyce Korvick, M.D., Deputy Director, Division of Gastroenterology Products, FDA, said “This new drug will be helpful to patients who experience severe constipation associated with the continuous use of morphine or other opioids, which are an important part of care for patients with late-stage, advanced illness.”

Relistor, which is administered as needed, is given as an injection. The patient must not receive more than one dose per 24-hour period. It is advised that a patient begin with one dose every two days. Relistor is not advised for people with known or suspected intestinal obstructions.

Common Side Effects Include-

— abdominal pain
— gas
— nausea
— dizziness
— diarrhea

Relistor use should be discontinued (with health care professional consultation) if the patient experiences severe diarrhea, vomiting, nausea or abdominal pain.

The sponsors, Wyeth Pharmaceuticals Inc., carried out clinical studies which demonstrated the safety and effectiveness of Relistor. There were two randomized, double-blind placebo-controlled studies with 287 patients, conducted over four months. 51% of the patients were women, and the median age of all the patients was 68 years. All patients in both studies had late-stage illnesses and a life-expectancy of up to six months. Before Relistor treatment the patients had either no bowel movement for at least two days or less than three bowel movements in the preceding week. It was found that patients receiving Relistor had a substantially higher rate of elimination compared to those on the placebo. Relistor’s safety and effectiveness for children has not been studied.

Relistor is manufactured by Wyeth Pharmaceuticals Inc., Philadelphia, PA., and Progenics Pharmaceuticals, Tarrytown, NY.

— Progenics and Wyeth Announce FDA has Approved Relistor (Wyeth web site)
— Relistor Prescribing Information (PDF)