Articles: narcotic-antagonists.
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Randomized Controlled Trial Clinical Trial
Low-dose naloxone does not improve morphine-induced nausea, vomiting, or pruritus.
We tested the hypothesis that low-dose naloxone delivered with intravenous (IV) bolus morphine to emergency department patients in pain would reduce nausea. ⋯ Addition of 0.25 microg/kg naloxone to bolus morphine does not improve nausea, pruritus, vomiting, or reduce use of rescue antiemetics when administered to emergency department patients in pain.
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Int J Obstet Anesth · Jan 2005
Randomized Controlled Trial Clinical TrialEffects of epidural naloxone on pruritus induced by epidural morphine: a randomized controlled trial.
Epidural morphine produces prolonged analgesia but has many side effects including pruritus. Naloxone is an antagonist that can reverse the side effects of morphine. ⋯ Continuous epidural infusion of naloxone combined with morphine is effective in reducing the incidence and severity of pruritus induced by epidural morphine.
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Opiates produce analgesia by activating mu opioid receptor-linked inhibitory G protein signaling cascades and related ion channel interactions that suppress cellular activities by hyperpolarization. After chronic opiate exposure, an excitatory effect emerges contributing to analgesic tolerance and opioid-induced hyperalgesia. Ultra-low-dose opioid antagonist co-treatment blocks the excitatory effects of opiates in vitro, as well as opioid analgesic tolerance and dependence, as was demonstrated here with ultra-low-dose naloxone combined with morphine. ⋯ Although chronic morphine decreased Gi/o coupling by mu opioid receptors, a pronounced coupling to Gs emerged coincident with a Gbetagamma interaction with adenylyl cyclase types II and IV. Co-treatment with ultra-low-dose naloxone attenuated both the chronic morphine-induced Gs coupling and the Gbetagamma signaling to adenylyl cyclase, while increasing Gi/o coupling toward or beyond vehicle control levels. These findings provide a molecular mechanism underpinning opioid tolerance and dependence and their attenuation by ultra-low-dose opioid antagonists.
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Clinical Trial Controlled Clinical Trial
[Antipruritic therapy with the oral opioid receptor antagonist naltrexone. Open, non-placebo controlled administration in 133 patients].
The perception of pruritus is modified by endogenous and exogenous opioids via central opiate receptors and can be suppressed with opioid receptor antagonists. The aim of this investigation was to describe the efficacy and safety of naltrexone, an orally active opiate antagonist, in the treatment of severe, otherwise intractable pruritus of varying origins. ⋯ The oral opiate antagonists may well be an effective, well-tolerated therapy for intractable pruritus in many diseases.