Effects of Naloxone Infusions in Patients with the Pruritus of Cholestasis: A Double-Blind, Randomized, Controlled Trial

1 August 1995 | Volume 123 Issue 3 | Pages 161-167

Objective: To determine whether endogenous opioids contribute to the pruritus of cholestasis by studying the effect of the opiate antagonist naloxone on the perception of pruritus and on scratching activity in patients with this form of pruritus.

Design: Double-blind, placebo-controlled, crossover trial with four periods.

Setting: Clinical research referral center.

Patients: 29 pruritic patients with liver diseases of various causes.

Intervention: Each patient received as many as two naloxone and two placebo solution infusions consecutively in random order. Each infusion lasted 24 hours.

Measurements: During the infusions, visual analog scores of pruritus were recorded every 4 hours while patients were awake; scratching activity independent of limb movements was recorded continuously.

Results: One patient had a mild reaction consistent with a naloxone-precipitated syndrome similar to opiate withdrawal. A significant 24-hour rhythm of scratching activity was seen in 7 of 11 patients for whom complete 96-hour data were collected. The mean of a visual analog score of the perception of pruritus (maximum, 10.0) recorded during naloxone infusions was 0.582 lower than that recorded during placebo infusions (95% CI, 0.176 to 0.988; P < 0.01). Furthermore, the ratio of the geometric mean hourly scratching activity during naloxone infusions to that during placebo infusions was 0.727 (CI, 0.612 to 0.842; P < 0.001) and was greater than 1.0 in only five patients.

Conclusions: Naloxone administration is associated with amelioration of the perception of pruritus and reduction of scratching activity in cholestatic patients. Because of the opioid receptor specificity of the action of naloxone, these findings support the hypothesis that a mechanism underlying the pruritus of cholestasis is modulated by endogenous opioids and suggest that opiate antagonists may have a role in the management of this complication of cholestasis.

Author and Article Information

From the National Institutes of Health, Bethesda, Maryland.
Requests for Reprints: Nora Valeria Bergasa, MD, Laboratory of the Biology of Addictive Diseases, Box 241, The Rockefeller University, 1230 York Avenue, New York, NY 10021.
Acknowledgments: The authors thank Drs. Michael W. Fried and Tse- Ling Fong for their participation in the conduct of this study; the nursing staff of Patient Unit 9-D, under the direction of Head Nurse Joyce Harris, for their vigilance; and Mr. Robert Ennis of the Applied Clinical Engineering Section, Biomedical Engineering and Instrumentation Program, National Center for Research Resources, for his assistance in the operation of the Scratching Activity Monitoring System.