Journal of psychopharmacology
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J. Psychopharmacol. (Oxford) · Jul 2007
Psychotropic drug prescribing in child and adolescent learning disability psychiatry.
This postal questionnaire study investigated the prescribing practices of a group of senior British psychiatrists who have responsibilities for children and adolescents with learning disabilities (mental retardation). The study revealed that all of the clinicians surveyed (n = 16) were prescribing psychotropic medication; psychostimulants and major tranquillizers represented the most frequently prescribed classes and, respectively, methylphenidate, risperidone, melatonin, sodium valproate and carbamazepine were the most frequently employed specific agents. ⋯ Many (14/16) clinicians reported difficulties in shared-care prescribing arrangements with General Practitioners. The study concludes that psychopharmacology is an established part of the psychiatric management of learning disabled children but acknowledges the need for the elaboration of clinical governance standards to this area of practice.
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J. Psychopharmacol. (Oxford) · May 2007
ReviewLow dose ketamine: a therapeutic and research tool to explore N-methyl-D-aspartate (NMDA) receptor-mediated plasticity in pain pathways.
Ketamine is a dissociative anaesthetic that has been used in the clinic for many years. At low, sub-anaesthetic doses, it is a relatively selective and potent antagonist of the N-methyl-D-aspartate (NMDA) receptor. It belongs to the class of uncompetitive antagonists and blocks the receptor by binding to a specific site within the NMDA receptor channel when it is open. ⋯ Hence, clinical use of ketamine as a pain treatment is very limited. Nevertheless, ketamine has served as a useful tool to provide a compelling rationale for developing other NMDA antagonists. Some of the new compounds of this class, particularly those acting at the NR2B subtype of the NMDA receptor, have shown promise in preclinical and clinical studies.
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J. Psychopharmacol. (Oxford) · Mar 2007
PRN prescribing in psychiatric inpatients: potential for pharmacokinetic drug interactions.
Medications are commonly prescribed to psychiatric inpatients on a PRN (pro re nata/as required) basis, allowing drugs to be administered on patient request or at nurses' discretion for psychiatric symptoms, treatment side effects or physical complaints. However, there has been no formal study of the pharmacokinetic implications of PRN prescribing. The objective of the study was to determine the prevalence of PRN drug prescription and administration, and to assess the potential for interactions involving CYP2D6 and CYP3A4 between drugs prescribed and administered to inpatients on psychiatry wards. ⋯ One fifth of patients were prescribed drug combinations interacting with CYP2D6 or CYP3A4 of potential clinical importance which included one or more drugs prescribed on a PRN basis. PRN prescribing is common among inpatients in psychiatry, and may lead to cytochrome P450 mediated interactions. Prescribers should be aware of the potential for unpredictability in plasma concentrations, side effects and efficacy which PRN prescribing may cause through these interactions, particularly in old age psychiatry and in treatment of acute psychosis.
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J. Psychopharmacol. (Oxford) · Mar 2007
Case ReportsRisperidone-to-methylphenidate switch reaction in children: three cases.
As atypical antipsychotics are increasingly used in the treatment of childhood behavioural disorders either as monotherapy or in combination with other medications, there is a need to know more about their safety, in particular during switching to and from methylphenidate treatment, as antipsychotics and methylphenidate have opposing effects on dopaminergic neurotransmission. This report is about three cases of children who developed severe adverse reactions during switching from risperidone to methylphenidate. The first patient was a 6-year-old boy, diagnosed with attention deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD). ⋯ In all the cases described here, it is only with the discontinuation of methylphenidate that the adverse reactions resolved and readministration of methylphenidate in two patients did not produce any adverse effect after a drug-free interval. Functional regulation of certain neuroreceptors during risperidone treatment may lead to altered behavioural responses upon switching to methylphenidate. Thus, a drug-free interval is recommended in order to prevent adverse reactions.
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J. Psychopharmacol. (Oxford) · Jan 2007
Controlled Clinical TrialEffects of psilocybin on time perception and temporal control of behaviour in humans.
Hallucinogenic psilocybin is known to alter the subjective experience of time. However, there is no study that systematically investigated objective measures of time perception under psilocybin. Therefore, we studied dose-dependent effects of the serotonin (5-HT)2A/1A receptor agonist psilocybin (4-phosphoryloxy-N, N-dimethyltryptamine) on temporal processing, employing tasks of temporal reproduction, sensorimotor synchronization and tapping tempo. ⋯ These objective effects on timing performance were accompanied by working-memory deficits and subjective changes in conscious state, namely increased reports of 'depersonalization' and 'derealization' phenomena including disturbances in subjective 'time sense.' Our study is the first to systematically assess the impact of psilocybin on timing performance on standardized measures of temporal processing. Results indicate that the serotonin system is selectively involved in duration processing of intervals longer than 2 to 3 seconds and in the voluntary control of the speed of movement. We speculate that psilocybin's selective disruption of longer intervals is likely to be a product of interactions with cognitive dimensions of temporal processing -presumably via 5-HT2A receptor stimulation.