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Biomedical subjects

P R Wilkinson

Publications and source records attributed to P R Wilkinson.

At least 19 recordsLinked to original sources

Comparison of bevantolol and atenolol in chronic stable angina.

A randomized, double-blind, parallel-group study design was used to compare the antianginal efficacy of bevantolol (200 to 400 mg) and atenolol (50 to 100 mg) each administrated once daily for 8 weeks in 39 patients with chronic stable angina. Assessments were made using 24-hour ambulatory monitoring and treadmill exercise testing performed 22 to 24 hours after the last dose of medication. Both groups were comparable at the end of the placebo phase. In the bevantolol group, exercise time increased from 7.9 +/- 0.7 minutes with placebo to 9.3 +/- 0.7 minutes with bevantolol (mean +/- standard error of the mean) (p less than 0.05). Time to 1 mm ST depression was unaltered. Rest and exercise heart rate decreased (p less than 0.0001 and less than 0.0005, respectively) as did exercise double product (p less than 0.0001). In the atenolol group exercise time increased from 7.1 +/- 0.7 minutes with placebo to 8.2 +/- 0.8 minutes with atenolol (p less than 0.02). Time to 1 mm ST depression increased (p less than 0.005) and rest and exercise heart rate and double product decreased (p less than 0.0001 and less than 0.05, respectively). When within-group differences between placebo and active drug were compared for bevantolol and atenolol, no significant differences were detected. Both drugs were well tolerated and reduced ambulatory heart rate throughout the 24 hours. This study confirms that both bevantolol and atenolol are effective antianginal agents. Bevantolol compares well with atenolol in the treatment of patients with chronic angina, and there was a similar response to exercise testing with the 2 drugs.

Adrenergic beta-Antagonists

Efficacy of transdermal glyceryl trinitrate in the treatment of chronic stable angina pectoris.

A study was carried out to assess the efficacy of a new transdermal preparation of glyceryl trinitrate (Transiderm-Nitro 5) in the 24 hour prophylaxis of angina and to determine the duration of effect of a single patch application. Twelve men with chronic stable angina were studied in a randomised, placebo controlled, double blind trial. By serial treadmill exercise testing a therapeutic effect was shown at three hours; the exercise time to angina and to 1 mm ST segment depression and the total exercise time were all significantly increased. At 24, 48, and 72 hours, however, no therapeutic effect was observed. Recent studies have shown a similar lack of effect at 24 hours for various forms of transdermal delivery systems. It is suggested that this lack of effect is due to the rapid onset of tolerance probably as a result of the constancy of blood concentrations obtained by this method of administration.

Administration, Topical

A comparative trial of clonidine, propranolol and placebo in the treatment of moderate hypertension.

1 A double-blind cross over trial between clonidine, propranolol and a placebo in patients with moderate hypertension has been performed. 2 Thirty-two patients completed the study which consisted of three treatment periods in random order of 3 months each. Patients had their blood pressure recorded by an unbiased observer using a random-zero machine. 3 Both clonidine and propranolol produced a significant reduction in blood pressure (P less than 0.01), which was apparent by the second week of therapy. Propranolol gave a greater reduction in pulse rate than clonidine (P less than 0.01) but clonidine also reduced the pulse rate significantly (P less than 0.05). There was no evidence of postural hypotension on either drug. Side-effects were more common with clonidine but these tended to wear off after several weeks of therapy. 4 Clonidine and propranolol were equipotent in reducing blood pressure, but clonidine has more initial side-effects than propranolol.

Adult

Total body and serum potassium during prolonged thiazide therapy for essential hypertension.

Serum-potassium and total body potassium (T.B.K.) were measured serially for 1 year in a group of eighteen patients with mild essential hypertension. The patients were receiving a single daily dose of 10 mg. bendrofluazide without potassium supplements. At 12 months the mean value for serum-potassium (3-86 mmol per litre) was significantly lower than the mean pre-treatment value (4-26 mmol per litre). There was no significant decrease in T.B.K. in the same period. Diastolic blood-pressure fell significantly, and there were no apparent side-effects from the medication. In the group as a whole, a reduction of about 1 mmol per litre in serum-potassium was associated with an average reduction of 10% in T.B.K., but there was a large individual variation. The amount of potassium loss during the period of study did not seem to be clinically significant. It is suggested that routine potassium supplements are not essential in the treatment of uncomplicated essential hypertension with thiazide diuretics.

Bendroflumethiazide