Effects Of Intravenous Cocaine Research Articles

Effects of oral cocaine on intravenous cocaine discrimination in humans.

This study was designed to evaluate the drug discrimination paradigm as a model for assessing the ability of potential agonist medications to block the effects of intravenous cocaine. Previous research has demonstrated that oral cocaine attenuated the subjective and physiological effects of intravenous cocaine injections, and in the absence of a known efficacious medication for cocaine use disorders, a proof-of-concept approach was used in which cocaine was acutely administered orally to block intravenous cocaine's discriminative-stimulus effects. During training, 11 cocaine-dependent participants were able to discriminate between intravenous saline and 20 mg/70 kg iv cocaine, and 8 of these participants completed the study. After training, participants ingested capsules containing either placebo or 300 mg/70 kg cocaine 60 min prior to the intravenous injection of different doses of cocaine during test sessions with no contingencies in place. Each cocaine dose was administered twice, once under each oral pretreatment condition. Training sessions were interspersed among the test sessions. Physiological and subjective effects were measured throughout each session. Oral cocaine moderately increased some of the subjective and physiological effects of the lower doses of intravenous cocaine, whereas effects at the higher doses were unaltered. Similar changes were seen for the discrimination results. Thus, although oral cocaine given acutely likely is not a viable treatment medication for cocaine dependence, the usefulness of the drug discrimination model in the evaluation of agonist treatment medications remains unclear.

Evidence for opponent-process actions of intravenous cocaine and cocaethylene

The affective response to cocaine (COC) has been suggested to follow a time-course and pattern that adheres to the prediction of opponent-process models of drug actions. While the initial impact of the drug is positive, within a few minutes that effect wanes and is replaced by an aversive state characterized by anxiety and drug craving. We have demonstrated this phenomenon in animals by showing that rats prefer distinctive environments associated with the immediate effects of intravenous COC (1.0 mg/kg) but avoid environments associated with the state present 15-min postinjection. Human addicts have reported taking ethanol with their COC as a means of attenuating the negative aftereffects of COC administration. The combination of ethanol and COC results in the production of cocaethylene (CE), a metabolite of COC having psychostimulant properties. The current study was devised to assess whether the immediate and delayed affective responses to CE might account for the self-medication strategy of COC addicts pretreating themselves with ethanol. Rats developed conditioned place preferences for environments paired with the immediate effects of a 1.44-mg/kg intravenous dose of CE (equimolar to a 1.0-mg/kg dose of COC). While no aversive effects were observed at 0, 5, or 15 min postinjection, reliable place avoidance was detected for an environment paired with the internal state present 30-min post-CE. These data are consistent with the view that the development of CE may account for efficacy of ethanol to delay and weaken the aversive aftereffects of COC.

Comparison of the reinforcing and anxiogenic effects of intravenous cocaine.

Comparison of the reinforcing and anxiogenic effects of intravenous cocaine.

Immediate Effects of Intravenous Cocaine on the Thoracic Aorta and Coronary Arteries: A Transesophageal Echocardiographic Study

STUDY OBJECTIVES AND DESIGN: Arterial vasoconstriction is thought to play a role in the etiology of cocaine-induced cardiovascular complications, but little is known about the immediate effects of cocaine on the thoracic aorta and coronary arteries. To examine these effects, we used transesophageal echocardiography to examine the thoracic aorta and coronary arteries before and immediately after intravenous (i.v.) cocaine (1.2 mg/kg) in 15 subjects. Immediately after cocaine infusion, average heart rate, systolic BP, and double product were increased compared with baseline (22%, 15%, 35%, respectively). There was no significant change in the diameters of the ascending aorta (27.5 vs 27.1 mm; p = 0.85), the descending aorta (19.8 vs 20.4 mm; p = 0.62), or the left main coronary artery (4.3 vs 4.7 mm; p = 0.15). However, there was a trend for an increase in coronary blood flow immediately after cocaine (226 vs 309 mL/min; p = 0.10). We conclude that in the 15 subjects studied, there was no evidence of thoracic aorta of coronary artery vasoconstriction immediately after i.v. cocaine. Instead, we found that the diameters of the thoracic aorta and the left main coronary artery were unchanged, and that there was a trend for augmentation of coronary artery blood flow.

Maternal/fetal cardiovascular effects of intravenous cocaine in unanesthetized, in utero, rats.

Maternal/fetal cardiovascular effects of intravenous cocaine in unanesthetized, in utero, rats.

Maternal/fetal cardiovascular effects of intravenous cocaine in unanesthetized, in utero, rats

Maternal/fetal cardiovascular effects of intravenous cocaine in unanesthetized, in utero, rats

Effects of intravenous cocaine on plasma cortisol and prolactin in human cocaine abusers

The aim of the present work was to examine the cortisol and prolactin responses to acute cocaine administration in human cocaine users. Each subject served as his own control during intravenous saline placebo and cocaine (40 mg) infusion sessions. Cocaine significantly elevated plasma cortisol but did not affect prolactin. The rise in cortisol coincided with an increase in heart rate and blood pressure after cocaine. In agreement with studies in animals, our data suggest that cocaine activates the hypothalamic-pituitary-adrenal axis in humans. However, based on the well-known importance of dopamine as a prolactin-inhibiting factor, the failure of cocaine to suppress prolactin in the present study raises questions concerning the role of dopamine in the mechanism of acute cocaine action in humans.

Effects of intravenous cocaine on cerebral glucose utilization in human polydrug abusers: Relations between regional metabolism and subjective responses

Effects of intravenous cocaine on cerebral glucose utilization in human polydrug abusers: Relations between regional metabolism and subjective responses

Evidence that cocaine slows cardiac conduction by an action on both AV nodal and His-Purkinje tissue in the dog

The effects of intravenous cocaine (2 mg/kg) were tested on several indices of cardiac electrical activity in sedated dogs. These included sinus rate, PR, AH, and HV intervals; AV nodal effective refractory period (AVNERP); ventricular effective refractory period; QRS duration; and the QT interval. Cocaine induced significant changes in six control animals with an intact-functioning autonomic nervous systems. After pharmacologic autonomic blockade with propranolol plus propantheline, cocaine increased the PR interval (+11 ± 4.0 ms, p < 0.05), primarily by slowing conduction at the AV nodal level. However, with constant atrial pacing at a rate above the sinus cycle length, prolongation of both the AH and the HV intervals (+15 ± 2.5 and + 6.7 ± 1.7 ms, respectively) occurred. There was also a significant increase in the AVNERP (+ 29 ± 5.9 ms, p < 0.05). Consistent with the observed rate-dependent HV prolongation, cocaine decreased the rate of rise of phase 0 of the transmembrane action potential of Purkinje fibers. These data indicate that cocaine impairs cardiac conduction by direct actions on AV nodal and His-Purkinje cells.

Effect of intravenous cocaine on uterine blood flow in the gravid baboon

Cocaine abuse during pregnancy is associated with adverse perinatal outcome, believed to be a result of potent vasoconstrictive effects that cocaine has on the maternal cardiovascular system. The direct effect of cocaine on the pregnant, nonhuman primates' uterine vasculature in vivo has not been examined. We investigated the effects of intravenous cocaine on maternal arterial blood pressure, uterine blood flow, and uterine vascular resistance in four unanesthetized, chronically instrumented pregnant baboons. Baboons were instrumented during the latter half of pregnancy, placing an ultrasonic flow probe around one uterine artery and catheters in the maternal inferior vena cava and aorta. Bolus intravenous cocaine hydrochloride doses of 0.05 mg/kg, 0.1 mg/kg, and 0.3 mg/kg by maternal weight were infused 30 minutes apart at least 5 days after surgical instrumentation. The maternal blood pressure rose 7.3% and 12.0% after the 0.1 mg/kg and 0.3 mg/kg cocaine infusions, respectively, and the uterine blood flow fell in a dose-dependent fashion 13.1% and 22.7%. Plasma norepinephrine levels rose in response to the 0.3 mg/kg cocaine infusion. These studies show that low doses of cocaine significantly reduce uterine blood flow in the pregnant baboon in a dose-dependent manner by increasing uterine vascular resistance.

Pregnancy increases cardiovascular toxicity to cocaine

The effects of intravenous cocaine on heart rate and blood pressure were studied in pregnant and oophorectomized nonpregnant ewes. In response to intravenous cocaine doses of 1.0 and 2.0 mg/kg, both pregnant and nonpregnant ewes demonstrated dose-dependent increases in systolic, diastolic, mean arterial, and pulse pressures with return to baseline by 30 to 60 minutes after cocaine administration. However, at both doses (1.0 and 2.0 mg/kg) pregnant ewes demonstrated greater increases in mean arterial pressure (+29.6%, +48.7%) than nonpregnant ewes (+15.6%, +27.7%) during the first 5 minutes after cocaine administration. Thereafter the responses were similar. Thus pregnancy increases the cardiovascular toxicity to cocaine.

Acute hemodynamic effects of intravenous cocaine in chronic cocaine abusers

Acute hemodynamic effects of intravenous cocaine in chronic cocaine abusers

Effects of intravenous cocaine are partially attenuated by haloperidol

We examined the effect of the dopaminergic blocking agent, haloperidol, on the subjective and physiologic response to cocaine in cocaine-using volunteers. Five subjects received cocaine (40 mg) or placebo administered intravenously 20 min following pretreatment with haloperidol (8 mg) or placebo intramuscularly in a randomized double-blind study design. Haloperidol pretreatment attenuated cocaine-induced increases in systolic and diastolic blood pressure but not heart rate. Pretreatment with haloperidol reduced subject ratings of pleasant sensations but had no effect on drug “rush.” Haloperidol (8 mg) has a small and limited effect on the subjective response to cocaine when given 20 min before cocaine.