Psychopharmacology
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Randomized Controlled Trial Comparative Study
Within-subject comparison of the psychopharmacological profiles of oral oxycodone and oral morphine in non-drug-abusing volunteers.
Nonmedical use and abuse of prescription opioids is a significant problem in the USA. Little attention has been paid to assessing the relative psychopharmacological profile (including abuse liability-related effects) of specific prescription opioids. ⋯ The psychopharmacological profile of oxycodone and morphine at equimiotic doses had many similarities; however, differences were found in producing abuse liability-related and dysphoric effects. In the medical community, it is commonly accepted that oral oxycodone is 1.5 to 2 times as potent as oral morphine in producing analgesia; using this ratio, although patients may experience similar degrees of pain relief, those receiving oxycodone may be experiencing stronger and potentially different psychopharmacological effects.
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Fluphenazine is a potent antipsychotic drug used to treat schizophrenia and other psychotic symptoms. Its clinical benefit is mainly mediated by the antagonism of dopamine D2 receptors. We have recently discovered, however, that fluphenazine is also a potent sodium channel blocker, a property that may offer additional therapeutical indications, including analgesia. ⋯ The inhibitory action of fluphenazine on ectopic afferent discharges may be due to its ability to block voltage-gated sodium channels, and this may also provide a mechanistic basis for the drug's antiallodynic effect in animal models of neuropathic pain. In summary, our study demonstrates that the classic antipsychotic drug fluphenazine has antiallodynic properties in multiple rodent models of nerve injury-induced neuropathic pain.
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Randomized Controlled Trial
Dopamine D2 receptor occupancy levels of acute sulpiride challenges that produce working memory and learning impairments in healthy volunteers.
In humans, the effects of dopaminergic agents administered systemically are less clear-cut than studies in experimental animals where agents can be applied locally in the brain. DA receptor occupancy could clearly contribute to the variance in findings, although this is typically not known. ⋯ Doses of sulpiride typically used in human cognitive studies produced low levels of DA D2 receptor occupancy compared to that considered efficacious in the treatment of schizophrenia. The levels of occupancy were sufficient to replicate impairments on a spatial working memory task and impair spatial learning. The relationship between occupancy and working memory was suggestive of presynaptic effects, although the precise mechanism underlying the impairment will require studies of wider ranges of occupancy within and outside of the striatum.
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Randomized Controlled Trial Comparative Study
How effective is it to sequentially switch among Olanzapine, Quetiapine and Risperidone?--A randomized, open-label study of algorithm-based antipsychotic treatment to patients with symptomatic schizophrenia in the real-world clinical setting.
Evidence on sequential trial with atypical antipsychotics has been scarce. ⋯ When the first atypical antipsychotic is inadequate, switching to the second is worth trying, although some remain treatment-refractory. Quetiapine may be inferior to Olanzapine and Risperidone in symptomatic patients.
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There is a close relationship between arousal and pupil diameter, decrease in the level of arousal being accompanied by constriction of the pupil (miosis), probably reflecting the attenuation of sympathetic outflow as sedation sets in. Paradoxically, sedation induced by benzodiazepines is not accompanied by miosis. ⋯ Diazepam-induced sedation is not accompanied by any change in either the sympathetic or parasympathetic influence on the iris.