Cardiovascular effects of 3,4-methylenedioxymethamphetamine. A double-blind, placebo-controlled trial.

BACKGROUND: The psychoactive stimulant 3, 4-methylenedioxymethamphetamine (MDMA), also known as "ecstasy," is widely used in nonmedical settings. Little is known about its cardiovascular effects. OBJECTIVE: To evaluate the acute cardiovascular effects of MDMA by using transthoracic two-dimensional and Doppler echocardiography. DESIGN: Four-session, ascending-dose, double-blind, placebo-controlled trial. SETTING: Urban hospital. PATIENTS: Eight healthy adults who self-reported MDMA use. INTERVENTION: Echocardiographic effects of dobutamine (5, 20, and 40 microg/kg of body weight per minute) were measured in a preliminary session. Oral MDMA (0.5 and 1.5 mg/kg of body weight) or placebo was administered 1 hour before echocardiographic measurements in three weekly sessions. MEASUREMENTS: Heart rate and blood pressure were measured at regular intervals before and after MDMA administration. Echocardiographic measures of stroke volume, ejection fraction, cardiac output, and meridional wall stress were obtained 1 hour after MDMA administration and during dobutamine infusions. RESULTS: At a dose of 1.5 mg/kg, MDMA increased mean heart rate (by 28 beats/min), systolic blood pressure (by 25 mm Hg), diastolic blood pressure (by 7 mm Hg), and cardiac output (by 2 L/min). The effects of MDMA were similar to those of dobutamine, 20 and 40 microg/kg per minute. Inotropism, measured by using meridional wall stress corrected for ejection fraction, decreased after administration of dobutamine, 40 microg/kg per minute, but did not change after either dose of MDMA. CONCLUSIONS: Modest oral doses of MDMA increase heart rate, blood pressure, and myocardial oxygen consumption in a magnitude similar to dobutamine, 20 to 40 microg/kg per minute. In contrast to dobutamine, MDMA has no measurable inotropic effects.

Buprenorphine and naloxone co-administration in opiate-dependent patients stabilized on sublingual buprenorphine.

Buprenorphine and naloxone sublingual (s.l.) dose formulations may decrease parenteral buprenorphine abuse. We evaluated pharmacologic interactions between 8 mg s.l. buprenorphine combined with 0, 4, or 8 mg of naloxone in nine opiate-dependent volunteers stabilized on 8 mg s.l. buprenorphine for 7 days. Combined naloxone and buprenorphine did not diminish buprenorphine's effects on opiate withdrawal nor alter buprenorphine bioavailability. Opiate addicts stabilized on buprenorphine showed no evidence of precipitated opiate withdrawal after s.l. buprenorphine-naloxone combinations. Buprenorphine and naloxone bioavailability was approximately 40 and 10%, respectively. Intravenous buprenorphine and naloxone produced subjective effects similar to those of s.l. buprenorphine and did not precipitate opiate withdrawal.

Buprenorphine and naloxone combinations: the effects of three dose ratios in morphine-stabilized, opiate-dependent volunteers.

Sublingual buprenorphine is a promising new treatment for opiate dependence, but its opioid agonist effects pose a risk for parenteral abuse. A formulation combining buprenorphine with the opiate antagonist naloxone could discourage such abuse. The effects of three intravenous (IV) buprenorphine and naloxone combinations on agonist effects and withdrawal signs and symptoms were examined in 12 opiate-dependent subjects. Following stabilization on a daily dose of 60 mg morphine intramuscularly, subjects were challenged with IV doses of buprenorphine alone (2 mg) or in combination with naloxone in ratios of 2:1, 4:1, and 8:1 (1, 0.5, or 0.25 mg naloxone), morphine alone (15 mg) or placebo. Buprenorphine alone did not precipitate withdrawal and had agonist effects similar to morphine. A naloxone dose-dependent increase in opiate withdrawal signs and symptoms and a decrease in opioid agonist effects occurred after all drug combinations. Buprenorphine with naloxone in ratios of 2:1 and 4:1 produced moderate to high increases in global opiate withdrawal, bad drug effect, and sickness. These dose ratios also decreased the pleasurable effects and estimated street value of buprenorphine, thereby suggesting a low abuse liability. The dose ratio of 8:1 produced only mild withdrawal symptoms. Dose combinations at 2:1 and 4:1 ratios may be useful in treating opiate dependence.

Buprenorphine and naloxone interactions in methadone maintenance patients.

Buprenorphine is undergoing clinical trials for the treatment of opiate addiction. Although the abuse liability of sublingual buprenorphine is low, reports of intravenous abuse have appeared. This study describes the physiologic and subjective effects of intravenously administered buprenorphine and naloxone given alone and in combination to methadone-maintained patients (40-60 mg/day). On four separate occasions at least 1 day apart, 6 subjects were administered either 0.2 mg buprenorphine, 0.1 mg naloxone, 0.2 mg buprenorphine and 0.1 mg naloxone in combination, or placebo. One male subject quit the experiment after three sessions because of excessive opiate withdrawal. Buprenorphine produced no significant physiologic or subjective effects. Naloxone produced marked opiate withdrawal symptoms. Buprenorphine in combination with naloxone produced characteristic physiologic and subjective opiate antagonist-like symptoms and signs. The parenteral abuse potential of the buprenorphine and naloxone combination is discussed.

Buprenorphine and naloxone interactions in opiate-dependent volunteers.

OBJECTIVE: Sublingual buprenorphine appears useful in the treatment of opiate dependence. A combination sublingual dose of buprenorphine and naloxone could have less potential for parenteral use by opiate-dependent individuals. To estimate the abuse potential of a combination formulation, we assessed the parenteral effects of a buprenorphine and naloxone combination in untreated heroin addicts. METHODS: Eight healthy, opiate-dependent daily users of heroin were given, under double-blind conditions on four separate occasions, either (1) 2 mg buprenorphine, (2) 2 mg naloxone, (3) 2 mg buprenorphine and 2 mg naloxone combined, or (4) placebo as a single intravenous infusion during a 30-second interval. Opiate agonist and antagonist physiologic and subjective effects were measured. Data were analyzed by analysis of variance. RESULTS: Buprenorphine increased opiate intoxication and relieved withdrawal. The buprenorphine and naloxone combination precipitated opiate withdrawal and was unpleasant and dysphoric in all subjects. Fifty percent of the subjects were unable to distinguish between naloxone alone and the combined medications during the first hour of testing. CONCLUSIONS: The buprenorphine and naloxone combination has a low abuse potential in opiate-dependent daily heroin users.

Improved performance 4 hours after cocaine.

Cocaine (2 mg/kg) was given orally to 13 healthy volunteers and physiologic, subjective, attentional and performance effects were measured over a period of 4 h. Posner's reaction time paradigm measured the effects of cocaine on performance and on attention to visual cues. Cocaine increased heart rate, systolic blood pressure and pupil diameter and reduced skin temperature. Physiologic effects, subjective rating of intoxication, and cocaine levels in saliva peaked at approximately 75 min and returned to precocaine levels within 3 h. In contrast, a reaction time measure of performance speed on the visual attention task showed improvement for 4 h after cocaine. A measure of covert attention in the cocaine condition failed to show the improvement which occurred in the placebo condition. Less fatigue was reported 4 h after cocaine than after placebo. Cocaine users may experience the drug's stimulant effects considerably longer than the euphoriant effects.