NALOXONE REDUCES FOOD-INTAKE IN HUMANS

Hypotheses generated from animal studies that the endogenous opioid system is an important modulator of food intake suggest that blockade of the system in humans should affect eating behavior. Seven normal volunteers were given 2 mg/kg naloxone or placebo on separate days in a double-blind, random but balanced cross-over experimental design. Compared to placebo, naloxone reduced significantly total food intake from preselected prepared trays served 2.75 and 7.75 h after drug administration (P < 0.02). The reduction was considerable (28%), and although the magnitude varied greatly among individuals, reduction occurred in each. This reduced food intake was not accompanied by a demonstrable alteration of the volunteers'' perceptions of their hunger. Further cautious experimental investigation of naloxone''s effects during long-term administration and in patients with eating disorders is warranted in light of its apparent effect of reducing food intake in humans while not decreasing their satiety.