The Journal of pharmacology and experimental therapeutics
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J. Pharmacol. Exp. Ther. · Jan 1994
Randomized Controlled Trial Clinical TrialA dose-response analysis of the subjective, psychomotor and physiological effects of intravenous morphine in healthy volunteers.
The purpose of this study was to characterize the subjective, psychomotor and physiological effects of morphine in healthy volunteers. Subjects (10 males and 2 females) without histories of opiate dependence were injected in an antecubetal vein with 0, 2.5, 5.0 or 10 mg/70 kg of morphine, by using a randomized, double-blind, cross-over design. Subjective effects, psychomotor performance and physiological measures were assessed immediately before the injection and for up to 5 hr afterward. ⋯ Miosis was induced by morphine. Most effects of morphine were dose-related, some effects peaked soon after morphine injection (e.g., increased stimulated and high ratings) and dissipated gradually, whereas other effects did not peak until later into the session (sedation or exophoria). Our results are fairly consistent with other studies examining morphine effects in healthy volunteers, and also indicate that the profile of morphine effects differ between healthy volunteers and those with a history of opiate dependence.
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J. Pharmacol. Exp. Ther. · Aug 1992
Randomized Controlled Trial Comparative Study Clinical TrialSubjective and behavioral effects of diphenhydramine, lorazepam and methocarbamol: evaluation of abuse liability.
The effects of orally administered placebo, diphenhydramine, lorazepam, methocarbamol and placebo were studied in volunteers with histories of recreational substance abuse including sedative/hypnotics. Placebo, diphenhydramine (100, 200 and 400 mg), lorazepam (1 and 4 mg) and methocarbamol (2.25 and 9 g) were tested in a randomized, double-blind crossover study using 14 subjects. Psychomotor and cognitive performance and subject- and observer-rated responses were measured daily before and for 5.5 hr after drug administration. ⋯ The present study clearly differentiated the behavioral and subjective profiles of diphenhydramine, lorazepam and methocarbamol. Consistent with its recognized low abuse liability, diphenhydramine produced fewer increases in measures of positive mood and more adverse effects. The considerable overlap in subjective effect measures of positive mood make further differentiation with respect to abuse liability difficult.
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J. Pharmacol. Exp. Ther. · Mar 1989
Randomized Controlled Trial Clinical TrialEvaluation of the abuse potential of methocarbamol.
The subjective and behavioral effects of p.o. administered methocarbamol, lorazepam and placebo were studied in a nonresidential group of adult male volunteers with histories of recreational substance abuse including sedative/hypnotics. In the first phase of the investigation, a dose run-up of methocarbamol (up to 12 g) was conducted in six subjects to determine appropriate doses. In the second phase, a randomized block cross-over study using 14 subjects was conducted. ⋯ Methocarbamol also increased ratings on measures indicating the emergence of dysphoric and other side effects at high doses. Both drugs impaired psychomotor and cognitive performance, with lorazepam generally producing greater effects than methocarbamol. The results indicate that methocarbamol, at doses well above those used therapeutically, has some potential to be abused by persons with histories of sedative/hypnotic abuse; however, this potential for abuse is probably decreased by the accompanying side effects at high doses and is probably less than that of lorazepam.
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J. Pharmacol. Exp. Ther. · Aug 1988
Randomized Controlled Trial Clinical TrialCigarette brand-switching: effects on smoke exposure and smoking behavior.
This study examined the effects of cigarette yield (Federal Trade Commission-determined deliveries of nicotine, tar and CO) on both biological exposure to smoke constituents and smoking behaviors. Smokers (N = 10) of high-yield cigarettes were switched in random order among five different commercially available cigarette brands with nicotine yields of 0.1, 0.4, 0.7, 1.1 (altered brand) and 1.0 (usual brand) mg and smoked each cigarette type for 5 days while a wide variety of assessments were performed. Steady-state cotinine and CO levels were substantially lower after 5 days of smoking ultra-low yield cigarettes (cotinine, 152 ng/ml; CO, 25 ppm) than when smoking usual-brand high-yield cigarettes (cotinine, 252 ng/ml; CO, 38 ppm). ⋯ However, filter vent-blocking of ultra-low yield cigarettes did not appear to occur on a consistent basis. Subjective reports indicated poor acceptability of lower-yield cigarettes. We conclude that switching to lower-yield cigarettes brings about substantial alterations in smoking behavior which are at least partially responsible for the observed biological compensation associated with these cigarettes.