The Effects of Naltrexone, an Oral ²-Endorphin Antagonist, in Children with the Prader-Willi Syndrome*

Children with the Prader-Willi syndrome have severe and often intractable hyperphagia unresponsive to medical or surgical treatment. Although the effect of opioid antagonists on suppressing appetite in humans has been inconsistent, we evaluated the effectiveness of a new opioid antagonist, naltrexone, in suppressing appetite in four obese adolescents with the Prader-Willi syndrome. Data were collected during the double blind oral administration of the drug and placebo for two 7-day periods. No clinical or biochemical toxicity was apparent during the naltrexone period, and measures of attention span, alertness, and mood did not change. Nutrient intake remained excessive during both the drug and placebo periods. Thus, naltrexone was ineffective in suppressing appetite, at least during the short term.