A drug used to
relieve constipation caused by treatment with opioids (pain
killers similar to morphine). It is used in patients with
pain caused by cancer or treatment for cancer or by other advanced disease.
Relistor binds to opioid
receptors outside the brain and may block the side effects
of opioid drugs without affecting their ability to relieve
pain. Relistor is a type of
peripheral opioid receptor antagonist. Also called methylnaltrexone bromide.