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Biomedical subjects

B Davies

Publications and source records attributed to B Davies.

At least 253 records · Page 14Linked to original sources
PubMed1976

The effect of tricyclic antidepressant drugs on the heart.

The effects on the heart rate and ECG of anaesthetised guines-pigs of amitriptyline, doxepin, imipramine and nortiptyline infused at 1.0 mg/kg/min until death were observed. In addition an in vitro study on guinea-pig atria was performed on the chronotropic and inotropic effects of these drugs and of desmethylimipramine and protriptyline at a concentration of 10(-5) M. The effect of sodium bicarbonate (3 mEq/kg i.v.) and propranolol (0.01--0.2 mg/kg i.v.) on amitriptyline and doxepin induced ECG changes was also assessed. A difference in the cardiac effects of the in vivo and in vitro model was observed. Guinea-pigs infused with doxepin survived significantly longer than those infused with amitriptyline, imipramine or nortriptyline. No statistically significant difference was found between the tricyclic drugs with respect to onset of widening of the QRS complex, increased PR and QT intervals. In the spontaneously beating atrial preparation doxepin was the most potent cardio-depressant. Sodium bicarbonate had no effect on arrhythmias induced by tricyclics, while propranolol, apart from the bradycardia induced, was without beneficial effect on the ECG. The guinea-pig provides a good model for studying the arrhythmogenic actions of tricyclic antidepressants.

Animals↗
PubMed1976

Observer variation and depressive phenomenology.

An investigation into observer variation and depressive phenomenology is described. A group of 6 clinicians independently completed a 43-item sheet for 20 depressed patients at the same clinical interview. The coefficient of agreements on the items are given. Patient variables and observer variables did not have any influence on the degree of agreement. There was also an agreement in the subtyping of depression.

Adjustment Disorders↗
PubMed1976

Cardiac effects of different tricyclic antidepressant drugs.

The effects of tricyclic antidepressants on the heart are reviewed. Statistically significant increases in heart rate and in atrioventricular conduction times were found following the administration of tricyclic drugs to 32 depressed patients. The method of His bundle electrocardiography was used to study atrioventricular conduction in ambulant patients and in patients admitted after an overdose of tricyclic antidepressant drugs. Distal conduction defects were frequently found in patients following tricyclic overdosage, but these were not seen with doxepin overdosage. Impaired distal conduction was also found in occasional patients on therapeutic doses of tricyclic drugs. Some animal experiments giving similar results to the above clinical findings are also described. The clinical implications of these findings are discussed.

Amitriptyline↗
PubMed1976

The measurement of plasma levels of tricyclic antidepressant drugs.

A double-isotope derivative dilution procedure for measuring plasma levels of Nortriptyline is described. The assay is specific, sensitive, precise and reproducible. Studies on the variation in steady-state plasma levels are described on a fixed oral dosage of nortriptyline. Between individual variations in steady-state plasma levels are large. Between day within individual variation is 15-20%. Dosage regime, time of blood sampling after last oral dose and the method of blood handling are unlikely to affect the steady-state plasma levels. Within an individual, the oral dose, duration of treatment and concomitant drug treatment are all important determinants of the steady-state plasma level.

Blood Preservation↗
PubMed1976

Rating scales as predictors of response to tricyclic antidepressants.

Fifty-three patients suffering from depressive illness were classified as 'responders' or 'non-responders' on the basis of an "amelioration score" of the Hamilton Rating Scale for depression after six weeks treatment with nortriptyline hydrochloride at 150 mgs. daily. A multivariate analysis of variance was performed on the four psychological rating scale scores used, to determine whether rating scales could predict treatment response to tricyclis antidepressants was found to be at 75% probability.ic anti-depressants was found to be at 757. probability.ic antidepressants. There was a significant difference between the two groups after adjustment for age. Subjects were then classified as 'non-responders' and 'responders' on the basis of their discriminant scores. The prediction of response to tricycl

Adult↗
PubMed1975

A comparative study of four depression rating scales.

Comparisons were made between the overall scores on the Beck, Hamilton, Zung and a visual analogue rating scale in a group of depressed patients. The comparisons were made initially and at one, two and three weeks. Significant correlations between the global scores were found on these depression scales. The value of these scales in clinical research studies in depression is discussed wirh special mention of the value of the visual analogue scale.

Adult↗