The effects of 100 mg of intranasal cocaine in acute alcohol intoxication (0.8 g/kg) were evaluated in eight experienced and nondependent healthy volunteers in a double-blind double-dummy, controlled, randomized, crossover clinical study. The combination of alcohol and cocaine produced greater increases in HR, rate-pressure product and pleasurable-related subjective effects (euphoria, well-being) compared with the effects of cocaine. The drug combination reduced the alcohol-induced sedation, but feelings of drunkenness were not significantly counteracted. Cardiovascular changes induced by the combination condition caused an increase in myocardial oxygen consumption that may be related to an increased risk of cardiovascular toxicity. The augmented subjective euphoria may explain why the drug combination is more likely to be abused than is cocaine or alcohol alone. Plasma cortisol concentrations were significantly higher after concomitant alcohol and cocaine use than with cocaine alone. The administration of cocaine did not alter alcohol-induced hyperprolactinemia. Although cocaine produced a slight decrease in plasma concentrations of prolactin when administered alone, it did not antagonize the effects of alcohol on prolactin secretion when alcohol and cocaine were given simultaneously. The combination increased cocaine and norcocaine plasma concentrations, and induced the synthesis of cocaethylene and norcocaethylene. The enhancement of cocaine effects in the drug combination may be due to initially increased cocaine plasma levels followed by the additive effect of cocaethylene, although a pharmacodynamic interaction could not be excluded.

Flunitrazepam is an hypnotic benzodiazepine marketed in different European countries. Epidemiological studies have shown that it is frequently abused by opioid addicts. In a survey, "liking" scores for flunitrazepam in methadone maintenance patients were higher than ratings for other benzodiazepines. A double-blind, placebo controlled, crossover clinical trial was conducted to assess the acute behavioral effects of flunitrazepam (0.50 and 2 mg) and triazolam (0.25 and 0.50 mg) in healthy male volunteers. Drug effects on physiological measures, psychomotor performance, and subjective rating scales, including specific questionnaires to evaluate abuse liability (e.g., ARCI or "liking" scores), were assessed before and 6 h after drug administration. Flunitrazepam 2 mg produced the most intense disruptive effects on all the performance tasks, triazolam 0.50 impaired performance except balance. All study drugs at all doses produced sedation symptoms in all or part of the subjective effects questionnaires. Only flunitrazepam 2 mg induced significative increases in some of the scales ("liking", "good effects", "high") that could be related to a possible abuse potential. The results seem to indicate that flunitrazepam, when administered to healthy subjects, produces some pleasurable subjective feelings, that could indicate a higher abuse liability of this drug as compared with other benzodiazepines.