Effects of intranasal cocaine on human learning, performance and physiology.

The behavioral and physiological effects of intranasally administered cocaine (placebo, 48, 96 mg/70 kg) were examined in eight recreational cocaine users under controlled laboratory conditions. The 48 and 96 mg doses of cocaine significantly improved subjects' performance on the Digit Symbol Substitution Test above levels observed either prior to drug administration or when placebo was administered. These effects were discernible for up to 120 min after cocaine administration. Cocaine had no statistically significant effects on learning and performance of ten-response sequences. The 48 and 96 mg doses increased heart rate and blood pressure for up to 180 min, and increased subject ratings of drug effects and decreased skin temperature for 60-90 min after drug administration. Cocaine produced no significant effects on the electrocardiogram. To our knowledge, this is the first experimental demonstration that acutely administered cocaine can improve behavioral performance in rested subjects. In addition, the duration of cardiac effects in this study was longer than previously reported with intranasal cocaine, perhaps due to the concurrent behavioral testing.