Nalmefene is a specific opioid receptor antagonist that inhibits the effects of endorphins in the central nervous system. Endorphins are believed to have a central role in the development of dependence disorders, such as alcoholism. It has been suggested that the neurobiological basis of impulse control disorders may have substantial similarity to that of addictions.
A phase II clinical study of nalmefene tablet was done to look at the treatment of impulse control disorders. A phase II study in patients suffering from pathological gambling demonstrated that nalmefene reduced gambling related urges and behavior statistically significantly compared to placebo.
Although in normal use, nalmefene suppresses appetitie in people, chronic nalmefene has been shown to cause weight gain in mice,
A 20 mg dose is considered clinically effective, and doses in that range have been used in studies. The half-life inside the body is 13.4 hours. At the clinically effective doses, the drug occupies the µ-opiod receptors even 26 hours after being given. Nalmefene is given in intravenously in tests.