The FDA has approved methylnaltrexone bromide subcutaneous injection for the treatment of opioid-induced constipation in patients taking opioids for chronic noncancer pain, according to a company press release.
Methylnaltrexone bromide (Relistor, Salix Pharmaceuticals and Progenics) is the only peripherally acting mu opioid receptor antagonist currently available for treating the cause of opioid-induced constipation (OIC) while avoiding interference with the opioid’s centrally acting analgesic properties, according to the release. The FDA initially approved methylnaltrexone bromide in 2008 for treatment of OIC in patients with advanced illness receiving palliative care who responded inadequately to laxative therapy.
“The approval and availability of Relistor for treating the underlying cause of OIC provides an important and welcomed advancement for many patients who experience constipation while taking opioids for chronic noncancer pain,” Bill Forbes, executive vice president, medical, research and development and chief development officer of Salix Pharmaceuticals, said in the release.
According to the release, the expanded approval comes in response to results from a phase 3 clinical trial involving 312 OIC patients that showed 12 mg methylnaltrexone bromide once daily for 4 weeks was safe and effective. It was well tolerated, and 59% of patients reported having three or more spontaneous bowel movements (SBM) per week compared with 39% of placebo patients. After the first dose, 33% of patients had SBM within 4 hours, and about half had SBM before the second dose.
“Patients generally experience a rapid bowel movement following administration of methylnaltrexone, often within 30 minutes,” Eugene Viscusi, MD, director of acute pain management, department of anesthesiology at Thomas Jefferson University, Philadelphia, said in the release. “Unlike laxatives, Relistor offers patients a relatively predictable timed response for a bowel movement. Additionally, most patients describe the sensation like a normal bowel activity. These attributes of treatment with Relistor are tremendous advantages.”