Predictors of cardiovascular response to smoked cocaine in humans.

The purpose of this study was to examine the predictors of heart rate and blood pressure changes following cocaine administration. Sixty-two smoked cocaine users received a single 0.4 mg/kg dose of smoked cocaine. Male sex, African American race, higher body weight and current marijuana use predicted a greater cardiovascular response to cocaine. In contrast, higher baseline blood pressure, heart rate, amount and frequency of current cocaine use and presence of current cocaine snorting predicted a diminished cardiovascular response to cocaine. Whether these predictors of the cardiovascular response to smoked cocaine in the laboratory also predict cardiovascular complications from long-term cocaine use needs to be studied further.

Comparing i.v. and non-i.v. cocaine users. Characteristics of a sample of cocaine users seeking to participate in research.

The authors examined differences between current intravenous (i.v.), past i.v., and no i.v. cocaine use among a sample of cocaine users on measures of drug use, medical history, psychiatric history, and criminal history. Past i.v. cocaine users were older than non-i.v. cocaine users. The current i.v. cocaine-using group included more white participants, and the non-i.v. group included more African Americans. Those with past or current i.v. use had more extensive drug use histories than non-i.v. users. Also, more current and past i.v. cocaine-using groups reported having been tested for HIV and reported testing positive for hepatitis. Former i.v. cocaine users reported more emergency room visits for complications stemming from cocaine use. They also reported more treatment for substance abuse and were convicted of more crimes. These results suggest that the route of administration is important in studying the characteristics of drug users.

Effects of cotinine on cigarette self-administration.

Previous studies have shown that cotinine, a metabolite of nicotine, antagonizes some of the effects of nicotine. One study showed that cotinine eliminates the beneficial effects of the nicotine patch in reducing cigarette withdrawal symptoms. The purpose of this study was to examine the effects of various doses of cotinine on cigarette self-administration. Subjects were randomly assigned to one of three doses of cotinine fumarate (40, 80 and 160 mg) and placebo, each for a period of 10 days, in a randomized order. Outcome variables included measures of nicotine intake and subjective responses to smoked cigarettes. Results showed no differences in the number of cigarettes smoked, carbon monoxide levels, and weights of cigarette butts across the various doses of cotinine and placebo. However, higher nicotine serum levels were observed in the 160 mg cotinine fumarate condition compared to placebo and to 40 mg cotinine fumarate. No systematic effects of cotinine on subjective responses to cigarettes were observed. Cotinine appears potentially to have a selective modulatory effect on nicotine withdrawal symptoms but not on cigarette smoking.