Answer
Sep 09, 2026 - 01:26 PM
RELISTOR (methylnaltrexone) can start working fairly quickly, although the timing varies by formulation and person.
For RELISTOR tablets, some patients have a bowel movement within 4 hours of the first dose. For RELISTOR injection, bowel movements can also occur within 4 hours, and in studies of patients with advanced illness, some responded in as little as 30 minutes.
Because the injection may work rapidly, the prescribing information recommends being close to a toilet after taking RELISTOR.
Individual response can vary, so not having a bowel movement within a few hours does not necessarily mean the medicine will not work.
