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Biomedical subjects

D B Frewin

Publications and source records attributed to D B Frewin.

At least 73 records · Page 4Linked to original sources
PubMed1982

Compliance with prescribed medications in visually compromised subjects.

The compliance with prescribed medications has been assessed in a group of 65 patients with compromised vision. It was found that the mean level of compliance in this group with respect to all medications was 64.2 +/- 2.1%, and that this level was significantly lower than that obtained for a group of 40 normally sighted individuals of comparable age. It is recommended that medication routines should be kept as simple as possible in patients with visual loss, and that suitable pill dispensers be used to enhance compliance where appropriate. Counselling and family support may additionally encourage adherence to drug regimens.

Aged↗
PubMed1982

The comparative effects of prilocaine, lignocaine and cocaine on the response of the rabbit ear artery to adrenaline and noradrenaline.

The effects of prilocaine, lignocaine or cocaine together with either adrenaline or noradrenaline was tested by applying combinations of these preparations to an isolated rabbit ear artery and measuring changes in intra-arterial pressure. Potentiation of the response was greatest with combinations of local anaesthetic and adrenaline; with noradrenaline the response was significantly potentiated only when the lowest concentrations of cocaine were used. It is suggested that some of this effect could be attributed to the differential inhibition by the local anaesthetic agents of the neuronal uptake of the catecholamines. This inhibition was prominent with all combination which contained adrenaline, but only occurred with noradrenaline when that vasoconstrictor agent was combined with cocaine.

Animals↗
PubMed1982

Pulmonary extraction of catecholamines in critically ill patients.

Plasma catecholamine concentrations in blood obtained simultaneously from the pulmonary and radial arteries of ten critically ill patients have been measured. The mean mixed venous concentrations of noradrenaline, adrenaline and dopamine were extremely high, noradrenaline 11.3 pmol/ml (SD 11.6), adrenaline 2.7 pmol/ml (SD 3.0) and dopamine 7.1 pmol/ml (SD 12.3). An appreciable drop in the concentrations occurred as the blood passed from the pulmonary artery to the radial artery (mean fall 24.1, 29.7 and 45.8% respectively). Four patients receiving a therapeutic dopamine infusion were also studied and demonstrated similar trends in catecholamine concentrations. The results suggest a substantial pulmonary clearance mechanism for all three catecholamines.

Aged↗
PubMed1981

Compliance with aerosol therapy in chronic obstructive lung disease.

The compliance of 114 patients with chronic airways disease to therapy with aerosol salbutamol and beclomethasone dipropionate was examined over two consecutive periods of approximately four weeks. Values ranging from 90-110 percent compliance were recorded for the two agents and a further increase in compliance was noted with both aerosols during the second month of surveillance. Over-use of salbutamol occurred in those patients who had been recently discharged from hospital. It was concluded that the high level of compliance was due to the symptomatic nature of the illness and the over-use of the bronchodilator was attributed to the usually prompt relief it provided.

Adolescent↗
PubMed1981

Compliance with anticoagulant drug therapy: a study on patients with prosthetic heart valves.

The compliance to anticoagulants of a group of patients with prosthetic heart valves has been assessed in the present study. It was found that the level of compliance to these agents was of the order of 90%. Additional compliance data were generated in relation to cardiac drugs and diuretics, which were taken concurrently by the patients. Significant differences were noted between the three categories, the diuretics being the group for which compliance was least. It is postulated that the formal routine adopted by clinics managing patients on anticoagulants greatly enhances compliance with these drugs. The inconvenience of the mode of action of diuretics is no doubt a significant factor in the poor compliance found with them.

Adult↗
PubMed1981

Vascular responses to REN-293 (2-amino-3[3, 5-dihydroxyphenyl]-1-propanol hydrochloride)--a new sympathomimetic agent.

In this study the effects of REN-293 have been examined on the rat tail artery "in situ'. It was found that the drug was totally dependent on the sympathetic nerves for its vasoconstrictor action. This action was blocked by phentolamine and attenuated by pre-treatment of the vessel with tyramine. When a comparative study of the vasoconstrictor effects of several sympathomimetics was performed, it was found that REN-293 was more potent than tyramine and ephedrine, but less so than etilefrine. It would appear that REN-293 is of interest as a pharmacological tool for examining sympathetic nerve function, but its usefulness in the therapy of orthostatic hypotension is likely to be limited, due to the very indirect nature of its sympathomimetic action.

Animals↗
PubMed1981

Changes in plasma catecholamine concentrations during endotracheal intubation.

The changes in arterial pressure and arterial concentrations of noradrenaline, adrenaline and dopamine were monitored in 16 patients undergoing endotracheal intubation. Significant increases in mean arterial pressure and plasma noradrenaline were noted. The increases in arterial pressure were associated with increases in noradrenaline concentrations. Adrenaline and dopamine concentrations did not change significantly following intubation. The results suggest a predominantly sympathetic response during intubation and the need for prophylaxis in patients at risk.

Adult↗
PubMed1981

Induction of microsomal drug metabolism in man and in the rat by exposure to petroleum.

To determine the effect of petroleum exposure on the activity of hepatic mixed function oxidase enzymes, salivary elimination kinetics of antipyrine were determined in 19 petrol station attendants and compared with 19 controls. Antipyrine half life in petrol station attendants was shorter than in controls. Microsomal preparations (10 000 x g supernatants) were prepared from six male Porton rats exposed to petrol vapour (5 ppm at an air flow rate of 41/min for eight hours a day for three weeks) and six control rats maintained under the same conditions without exposure to petrol vapour. The rates of oxidative metabolism of antipyrine, aminopyrine, ethylmorphine, aniline, and benzo(a)pyrene were all increased by more than 45% in the petrol-exposed rats. The results indicate that petrol vapour is a moderately potent inducer of mixed function oxidase activity in rats, and that occupational exposure to petroleum may result in enhanced microsomal drug metabolism.

Adolescent↗
PubMed1980

Atenolol in hypertension: follow-up of patients crossed over to this agent from propranolol, pindolol or metoprolol.

Thirty hypertensive patients treated with a drug regimen which contained a beta-receptor antagonist (either propranolol, pindolol or metoprolol) exhibited an improvement in blood pressure control when atenolol was substituted for the corresponding beta-blocker in the drug regimen. Additional benefits noted were a reduction in concomitant drug therapy and an improvement in reported side effects. Atenolol caused a significant decrease in heart rate in the group for which the mean follow-up period was 23.6 months.

Adult↗
PubMed1980

The effect of sympathomimetic agents on noradrenaline efflux from a blood vessel.

The effect of several sympathomimetic agents on the efflux of noradrenaline and its metabolites has been evaluated using the ventral artery of the rat tail as the experimental model. This vessel is richly endowed with sympathetic nerves and is therefore well suited to examine the efflux patterns of that transmitter. Etilefrine, tyramine, ephedrine and REN-293 were all found to increase the efflux of 3H-noradrenaline and/or 3H-DOPEG to different degrees from the artery. Possible reasons for this variation in metabolite efflux are discussed.

Animals↗
PubMed1980

Plasma potassium levels in hypertensive patients receiving fixed-combination diuretic therapy.

Among 54 patients attending a hospital hypertension clinic and receiving the fixed-combination diuretic Moduretic (hydrochlorothiazide 50 mg, amiloride 5 mg), there was a 44.4% incidence of hypokalaemia. The mean drop in plasma potassium level was 0.69 mmol/L (P less than 0.0001), the mean low level being 2.81 mmol/L. Seventy-four per cent of falls occurred within 52 weeks of the start of therapy, 19.5 weeks being the average period between a normal and a low plasma potassium level. There was no difference in the fall in potassium level between male and female subjects, and beta-blockers were not obviously protective, although there was a statistically significant smaller fall in potassium level in females treated with them. The clinical significance of the unexpected hypokalaemia is uncertain; but even with fixed-combination diuretics, it remains necessary to monitor the plasma potassium level regularly in order to avoid complicating situations. The results of the present study would cast doubt on the efficacy of 5 mg of amiloride with 50 mg of hydrochlorothiazide in fixed-combination form in preventing hypokalaemia in this clinical situation.

Adult↗
PubMed1980

Postoperative epilepsy: a double-blind trial of phenytoin after craniotomy.

In a double-blind trial of phenytoin for the prevention of postoperative epilepsy in craniotomy patients, epilepsy was observed in 7.9% (8/101) of patients treated with phenytoin and in 16.7% (17/102) of those receiving placebo. Therapeutic drug levels were associated with a significant reduction in the frequency of epilepsy. Three-quarters of the fits occurred within a month of cranial surgery. High rates of epilepsy have been observed after cranial surgery in patients with meningioma, aneurysm, and head injury with or without intracranial clots, and routine prophylaxis with phenytoin would seem to be indicated in such patients.

Clinical Trials as Topic↗
PubMed1980

Pindolol in orthostatic hypotension: possible therapy?

The association of recumbent hypertension with orthostatic hypotension provides a clinical situation which is extremely difficult to treat. The present report describes two patients who presented with this disorder and evaluates the use of pindolol in their management.

Humans↗
PubMed1980

Comparative enzyme-inducing effects of chlorpromazine and fluphenazine therapies in psychotic patients.

Antipyrine elimination kinetics were measured in psychotic patients receiving either long-term chlorpromazine or fluphenazine decanoate therapy and in non-medicated control subjects. Patients receiving chlorpromazine metabolised antipyrine faster than the controls while, in patients receiving fluphenazine decanoate, there was not change. The results suggest that long-term chlorpromazine therapy induced the activity of drug-metabolising enzymes, whereas fluphenazine decanoate therapy had no effect.

Adult↗