Naltrexone in the treatment of pruritus

Naltrexone is a cyclopropyl derivative of oxymorphone which behaves as a competitive antagonist of opioid receptors. Naltrexone is usually used in weaning opioid-dependent patients. The rationale behind the use of naltrexone in the treatment of chronic, diffuse and therapy-resistant pruritus is based on the fact that the opioids used in the treatment of chronic pain (in particular morphine) often cause a type of pruritus which is resistant to traditional antipruritic drugs, and that using naltrexone prevents this pruritus from appearing. Furthermore, the degranulation of basophils and mastocytes and histamine release which are caused by morphine, are inhibited by naltrexone. Naltrexone has therefore been successfully used in cholestatic and uremie pruritus. The authors present the preliminary results of a clinical study on the use of naltrexone in patients with chronic pruritus due to skin diseases.