Cocaine augments peripheral benzodiazepine binding in humans.

Acute cocaine administration has been reported to alter central benzodiazepine binding in animals. The authors examined the effects of chronic cocaine use on binding at the peripheral benzodiazepine site on platelets in cocaine users (N = 8), heavy ethanol users (N = 4), and controls (N = 7). The groups were matched for age and sex. None of the subjects reported recent benzodiazepine use, but neither serum nor urine testing was performed. Apparent affinity at the peripheral benzodiazepine site was similar in the three groups. However, the number of binding sites was significantly greater in cocaine users. These results indicate that cocaine use affects peripheral benzodiazepine binding in humans and might also alter central benzodiazepine effects.