Hypothalamic-pituitary-adrenal axis response to oral naltrexone in alcoholics during early withdrawal.

Background: It is thought that naltrexone may play a significant role in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis response to stress. We investigated the HPA axis response following single-dose oral naltrexone administration in the early phase of alcohol withdrawal.

Methods: Cortisol and adrenocorticotrophic hormone (ACTH) responses to naltrexone were measured in alcohol-dependent males (n=23) and in healthy males (n=20). Blood samples were collected for cortisol and ACTH measurements before administering (0 min) 50 mg naltrexone at 08.00 in the morning, and at 60, 90, 120 and 180 min after administering naltrexone.

Results: Naltrexone administration resulted in a significant ACTH response in the patients while cortisol and ACTH responses were found to be significant in the controls. Cortisol response was not large enough to reach significance in the patients. ACTH level changes as a response to naltrexone in the patients were lower than that in the controls.

Conclusions: The study revealed blunted cortisol and attenuated ACTH responses to naltrexone in early alcohol withdrawal. This study may have shown impairment in adrenal and pituitary levels during alcohol withdrawal.