Biomedical subjects

S J C Davies

Publications and source records attributed to S J C Davies.

3 recordsLinked to original sources

PubMed2004

Potential for drug interactions involving cytochromes P450 2D6 and 3A4 on general adult psychiatric and functional elderly psychiatric wards.

AIMS: To assess the potential for interactions involving cytochromes P450 2D6 (CYP2D6) and 3A4 (CYP3A4) between drugs prescribed in a city in-patient psychiatric service. METHODS: Prescription information was obtained from all 236 patients in general adult wards and all 87 patients in functional elderly wards under a city psychiatric service. The frequencies with which combinations of drugs expected to interact via CYP2D6 or CYP3A4 were documented and compared between these two settings. RESULTS: All 2089 drug prescriptions, of which 1237 (59%) were administered, were analyzed. One hundred and seventy-two patients (73%) on adult wards and 59 (68%) on functional elderly wards were prescribed at least one drug metabolized by and/or inhibiting CYP2D6, the difference being nonsignificant (95% confidence interval on the difference -6.3%, 16.4%). Anticipated interactions from 62/82 CYP2D6-related combinations prescribed on adult wards (27/100 patients) and 19/30 prescribed to elderly patients (22/100 patients) were judged to be clinically important or potentially clinically important. The proportion of patients on functional elderly wards prescribed at least one drug interacting with CYP3A4 (87%) was significantly greater than that for patients on adult wards (57%, P < 0.001). The frequency of interactions involving CYP3A4 was significantly greater on functional elderly than adult wards (43/100 vs 22/100 patients, P < 0.025, 95% confidence interval on the difference 4, 38/100). CONCLUSIONS: Our findings confirm extensive polypharmacy on general adult psychiatric and functional elderly psychiatric wards. A substantial proportion of patients were receiving combinations of drugs that interact with CYP2D6 and/or CYP3A4, many of which are known to produce clinically important interactions. Doctors practising in old age psychiatry should be aware that patients on functional elderly wards are at increased risk of clinically important CYP3A4 interactions. Psychiatrists should consider the pharmacokinetic implications of drugs prescribed for use 'as needed', because of the potential for unpredictable interactions.

Adolescent↗

PubMed2003

Addiction.

Alcohol and psycho-active substance misuse has far-reaching social, psychological and physical consequences. Advances in neuroimaging technology have allowed neurobiological theories of addiction to become better characterized. We describe the neurobiology of dependence, withdrawal, abstinence and craving states in alcohol, stimulant and opiate misuse. Structural neuroimaging techniques such as CT and MRI with new analytical approaches such as voxel-based morphometry have shown wide-spread changes in stimulant and opiate abuse and atrophy, particularly in the frontal lobes, in alcoholism. Functional neuroimaging techniques such as PET, SPECT and fMRI reveal altered regional cerebral activity by all drugs of abuse. The neurochemistry of addiction, particularly involving dopamine, serotonin, opiate and GABA, has been studied with PET and SPECT and similarities between all drugs of abuse have been found such as reduced dopaminergic markers. The evidence derived from these advances in neuroimaging is likely to herald the emergence of new biological treatments in this important field.

Brain↗

PubMedDate not supplied

No evidence that panic attacks are associated with the white coat effect in hypertension.

The authors aimed to determine whether hypertensive patients with panic attacks or panic disorder have a larger white coat effect (difference between clinic blood pressure measured under standard conditions and mean daytime ambulatory blood pressure) than hypertensive patients without panic attacks. White coat effect was compared in a hospital hypertension clinic between 24 patients with panic attacks in the previous 6 months (12 with panic disorder) and 23 hypertensive controls. There were no significant differences between cases and controls in clinic blood pressure, mean daytime ambulatory blood pressure, or white coat effect (18/3 vs. 19/6 mm Hg; difference for systolic, -1.9 mm Hg; 95% confidence interval, -15.8 to +12.0; difference for diastolic, -3.0 mm Hg; 95% confidence interval, -10.2 to +4.3). Comparing only patients with panic disorder with controls, there were again no significant differences in clinic blood pressure, mean daytime ambulatory blood pressure, or white coat effect. This study provides no evidence for an exaggerated white coat effect in hypertensive patients who have experienced panic attacks or panic disorder. However, only larger studies could exclude differences in white coat effect <12/4 mm Hg, or an exaggerated white coat effect in a minority of patients with panic attacks.

Blood Pressure↗