The Journal of pharmacology and experimental therapeutics
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J. Pharmacol. Exp. Ther. · Feb 2012
Randomized Controlled TrialEffects of the α₂-adrenergic agonist clonidine on the pharmacodynamics and pharmacokinetics of 3,4-methylenedioxymethamphetamine in healthy volunteers.
The mechanism of action of 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) involves the carrier-mediated and potentially vesicular release of monoamines. We assessed the effects of the sympatholytic α₂-adrenergic receptor agonist clonidine (150 μg p.o.), which inhibits the neuronal vesicular release of norepinephrine, on the cardiovascular and psychotropic response to MDMA (125 mg p.o.) in 16 healthy subjects. The study used a randomized, double-blind, placebo-controlled crossover design with four experimental sessions. ⋯ Clonidine did not affect the psychotropic effects or pharmacokinetics of MDMA. The lack of an interaction of the effects of clonidine and MDMA indicates that vesicular release of norepinephrine, which is inhibited by clonidine, does not critically contribute to the effects of MDMA in humans. Although clonidine may be used in the treatment of stimulant-induced hypertensive reactions, the present findings do not support a role for α₂-adrenergic receptor agonists in the prevention of psychostimulant dependence.
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J. Pharmacol. Exp. Ther. · Dec 2009
Randomized Controlled TrialAnti-inflammatory properties of a novel N-phenyl pyridinone inhibitor of p38 mitogen-activated protein kinase: preclinical-to-clinical translation.
Signal transduction through the p38 mitogen-activated protein (MAP) kinase pathway is central to the transcriptional and translational control of cytokine and inflammatory mediator production. p38 MAP kinase inhibition hence constitutes a promising therapeutic strategy for treatment of chronic inflammatory diseases, based upon its potential to inhibit key pathways driving the inflammatory and destructive processes in these debilitating diseases. The present study describes the pharmacological properties of the N-phenyl pyridinone p38 MAP kinase inhibitor benzamide [3- [3-bromo-4-[(2,4-difluorophenyl)methoxy]-6-methyl-2- oxo-1(2H)-pyridinyl]-N,4-dimethyl-, (-)-(9CI); PH-797804]. PH-797804 is an ATP-competitive, readily reversible inhibitor of the alpha isoform of human p38 MAP kinase, exhibiting a K(i) = 5.8 nM. ⋯ Finally, PH-797804 reduced tumor necrosis factor-alpha and interleukin-6 production in clinical studies after endotoxin administration in a dose-dependent manner, paralleling inhibition of the target enzyme. Low-nanomolar biochemical enzyme inhibition potency correlated with p38 MAP kinase inhibition in human cells and in vivo studies. In addition, a direct correspondence between p38 MAP kinase inhibition and anti-inflammatory activity was observed with PH-797804, thus providing confidence in dose projections for further human studies in chronic inflammatory disease.
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J. Pharmacol. Exp. Ther. · Dec 2007
Randomized Controlled TrialPharmacological interaction between 3,4-methylenedioxymethamphetamine (ecstasy) and paroxetine: pharmacological effects and pharmacokinetics.
3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") is increasingly used by young people for its euphoric and empathic effects. MDMA can be used in combination with other drugs such as selective serotonin reuptake inhibitors. A clinical trial was designed where subjects pretreated with paroxetine, one of the most potent inhibitors of both 5-hydroxytryptamine reuptake and CYP2D6 activity, were challenged with a single dose of MDMA. ⋯ These data show that pretreatment with paroxetine significantly attenuates MDMA-related physiological and psychological effects. It seems that paroxetine could interact with MDMA at pharmacodynamic (serotonin transporter) and pharmacokinetic (CYP2D6 metabolism) levels. Marked decrease in the effects of MDMA could lead users to take higher doses of MDMA and to produce potential life-threatening toxic effects.
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J. Pharmacol. Exp. Ther. · Jan 2002
Randomized Controlled Trial Clinical TrialEffects of subcutaneous methylnaltrexone on morphine-induced peripherally mediated side effects: a double-blind randomized placebo-controlled trial.
Methylnaltrexone, the first peripheral opioid receptor antagonist, has the potential to prevent or reverse opioid-induced peripherally mediated side effects without affecting analgesia. In previous human trials, we demonstrated that intravenous methylnaltrexone prevented morphine-induced delay in gastrointestinal transit time. We also observed that the compound decreased some of the morphine-induced troublesome subjective effects. ⋯ In addition, subcutaneous methylnaltrexone significantly decreased morphine-induced subjective rating changes. Pharmacokinetic data after subcutaneous drug injection were compared to the data obtained from previous intravenous and oral administrations. Our results suggest that subcutaneous methylnaltrexone may have clinical utility in treating opioid-induced constipation and reducing opioid-induced unpleasant subjective symptoms.
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J. Pharmacol. Exp. Ther. · Jul 1999
Randomized Controlled Trial Clinical TrialPeripheral effects of the kappa-opioid agonist EMD 61753 on pain and inflammation in rats and humans.
The objective of the present study was to evaluate the effects of EMD 61753 (asimadoline), a kappa-opioid receptor agonist with restricted access to the central nervous system, on postoperative pain in patients who underwent knee surgery and on nociceptive thresholds and inflammation in rats treated with Freund's complete adjuvant. Patients treated with EMD 61753 (10 mg p.o.) tended to report an increase in pain, as evaluated by a visual analog scale and by the time to the first request for and the total amount of supplemental analgesic medication. The global tolerability of EMD 61753 was assessed as significantly inferior to that of a placebo by the investigator. ⋯ EMD 61753 (1.6 mg)-induced analgesia was blocked by the peripheral opioid receptor antagonist naloxone methiodide (2.5-10 mg/kg s.c.) and by the kappa receptor antagonist nor-binaltorphimine (0.1 mg; i.pl.). In contrast, EMD 61753 (1.6 mg)-induced hyperalgesia and increases in paw volume and paw temperature were blocked neither by naloxone methiodide (10-40 mg/kg s.c.) nor by dizocilpine maleate (0.003-0.009 mg i.pl.), a N-methyl-D-aspartic acid receptor antagonist. These data show differentially mediated peripheral actions of EMD 61753: kappa-opioid receptor-induced analgesia and nonopioid, non-N-methyl-D-aspartic acid hyperalgesic and proinflammatory effects.