Naltrexone is an orally bioavailable antagonist of opioid receptors that shows preference for the μ-receptor over the κ- and δ-receptors (Ki = 0.30, 0.82, and 16 nM, respectively). By blocking signaling through the μ-opioid receptor, naltrexone reduces hedonic (reward) signaling associated with alcohol and opioid dependency. Naltrexone also halts the progression of experimental autoimmune encephalomyelitis, reverses neurological deficits, and prevents the onset of neurological dysfunction in mice. It also improves mental health quality of life in humans with multiple sclerosis.
