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Biomedical subjects

R G Wilcox

Publications and source records attributed to R G Wilcox.

At least 73 records · Page 4Linked to original sources
PubMed1984

The effects of acute or chronic ingestion of propranolol or metoprolol on the metabolic and hormonal responses to prolonged, submaximal exercise in hypertensive men.

We have studied the effects of single oral doses of, and of 28 days treatment with, placebo, propranolol or metoprolol, on the metabolic and hormonal responses to prolonged exercise in hypertensive men. Blood glucose levels fell during exercise on all occasions. No additional effects of the beta-adrenoceptor antagonists, compared to placebo, were observed. The exercise-induced increase in plasma potassium was enhanced after a single dose of propranolol or metoprolol, and also after chronic treatment with propranolol. Chronic treatment with either drug led to an increase in plasma potassium levels at rest. The growth hormone response to exercise was potentiated by a single dose of metoprolol or propranolol, and after chronic treatment with the drugs. A single dose of propranolol (but not metoprolol) was associated with a marked increase in plasma cortisol and adrenaline levels during exercise. After chronic treatment no such increase occurred. In both the acute and chronic phases of the study, blood lactate levels were higher during exercise in the presence of either propranolol or metoprolol compared to placebo, whereas non-esterified fatty acid levels were lower. A single dose of metoprolol produced a significantly greater reduction in blood glycerol levels during exercise than a single dose of propranolol. After chronic treatment, both propranolol and metoprolol produced similar reductions in blood glycerol levels during exercise. After a single dose, both drugs significantly augmented the increase in plasma noradrenaline levels during exercise. A similar effect was seen after chronic treatment.

Blood Glucose↗
PubMed1982

Is exercise good for high blood pressure?

Ten men with uncomplicated essential hypertension (mean standing blood pressure 165/109 mm Hg) and 10 normal controls matched for age and weight were studied for the hypotensive potential of moderate exercise. Tests were conducted on a treadmill set to induce a steady heart rate of 120 beats/min and performed over five 10-minute periods separated by three minutes' rest and finishing with 30 minutes' sitting quietly in a chair.During exercise the mean systolic pressures were identical in the hypertensive patients and controls (175+/-SEM 5 mm Hg), the controls therefore sustaining an appreciably greater increase in pressure. During the 30-minute rest period after the tests both the control and hypertensive groups showed a significant and sustained fall in absolute systolic pressures as compared with pre-exercise values (p <0.001), the mean percentage reductions being 22% and 25% respectively.If a fall in blood pressure after exercise is maintained for four to 10 hours, then a "good walk" twice a day might be reasonable treatment for mild hypertension. Studies are continuing to determine the amount of exercise needed and the duration for which the reduction in blood pressure is maintained.

Adult↗
PubMed1982

Comparison between atenolol and nadolol in essential hypertension at rest and on exercise.

1 The effects of 4 week treatment periods of once-daily atenolol 100 mg, nadolol 80 mg, nadolol 160 mg and placebo on resting and exercise heart rate and blood pressure were compared in a single-blind crossover trial in fifteen patients with essential hypertension. 2 Both atenolol and nadolol, irrespective of dose, reduced resting and exercise blood pressures to the same extent. 3 Nadolol caused a greater bradycardia both at rest and during exercise than did atenolol, thereby effecting a greater reduction in double-product. 4 During progressive treadmill exercise neither atenolol nor nadolol prevented a linear increase in heart rate and blood pressure which were parallel to, but at a lower level than, that produced by placebo. 5 In each individual patient the magnitude of the hypotensive effect produced by one drug was similar to that produced by the other. 6 All the treatment periods resulted in the same linear increase in the patients' perceived exertion scores during exercise despite marked differences in haemodynamic responses evoked by the beta-adrenoceptor blockers compared with placebo. 7 Neither atenolol or nadolol produced any significant change in peak expiratory flow rate compared with placebo.

Adrenergic beta-Antagonists↗
PubMed1981

Prognosis of patients with "chest pain ?cause".

All 662 patients admitted to the two coronary care units in Nottingham during 12 consecutive months were followed up prospectively for one year. At the time of discharge from hospital they were categorised according to set criteria into the following diagnostic groups: definite, probable, or possible myocardial infarction; ischaemia heart disease without infarction; chest pain ?cause; and other diagnoses. Eighty-nine patients (13% of admissions) were categorised as having chest pain ?cause. No deaths occurred among these patients during the observation period, although two were readmitted with myocardial infarction. Patients with chest pain ?cause had few problems during the year after admission, and at the end of that time 75% were in their original employment. Patients admitted with ischaemic heart disease had a similar death rate (between six weeks and one year after admission) to those with myocardial infarction, and only 36% were in their original employment one year after admission. Chest pain ?cause is a clinically useful diagnostic category to which patients may be allocated after only simple investigations.

Adult↗
PubMed1981

Acute intervention studies in patients with myocardial infarction using atenolol, propranolol, oxprenolol and disopyramide phosphate.

The value of beta-blockade and of disopyramide phosphate in the immediate treatment of patients with suspected acute myocardial infarction was assessed in two placebo controlled trials. In the first study 388 patients with suspected acute myocardial infarction were randomly allocated to treatment with propranolol, atenolol, or placebo, and when analysed on an initial intention to treat basis there was no significant difference between the three groups in respect of the mortality at one year. In addition, there was no evidence to suggest that either atenolol, or propranolol reduced the incidence of 'serious' ventricular arrhythmias in the coronary care unit. In the second study 473 patients with suspected acute myocardial infarction were randomly allocated to treatment with oxprenolol, disopyramide phosphate, or placebo. Again no significant differences were seen with respect to the mortality at six weeks. There was, however, a significantly increased incidence of heart failure in the group which received disopyramide phosphate. Patients who received this drug also showed a reduced number of dysrhythmic episodes on 24-hour ECG recordings, but this trend did not achieve statistical significance. These results suggest that none of the three beta-blockers tested nor disopyramide phosphate is likely to reduce the mortality from acute myocardial infarction when given prophylactically, although disopyramide phosphate does reduce the incidence of 'serious' ventriicular arrhythmias.

Adrenergic beta-Antagonists↗
PubMed1981

Comparative study of atenolol, metoprolol, metoprolol durules, and slow-release oxprenolol in essential hypertension.

Twenty-five patients with moderate essential hypertension (standing diastolic blood pressure 100-125 mmHg, phase 5) completed a single-blind placebo-controlled cross-over study comparing four week periods of treatment with atenolol 100 mg, metoprolol 100 mg, metoprolol durules 200 mg, slow-release oxprenolol 160 mg, and slow-release oxprenolol 320 mg respectively. All the drugs were significantly better than placebo at reducing resting blood pressure at 24 hours. Atenolol produced the greatest mean reduction of pressure and was the most effective drug for most patients, though the differences between atenolol and metoprolol durules were not statistically significant. These two drugs, however, were significantly more effective than the remainder. A similar ranking was seen with respect to the reduction of the blood pressure and heart rate response to exercise. None of the treatments had any significant effect on the patients' rating of perceived exertion during the exercise test.

Adrenergic beta-Antagonists↗
PubMed1980

Randomised placebo-controlled trial comparing oxprenolol with disopyramide phosphate in immediate treatment of suspected myocardial infarction.

473 patients with suspected acute myocardial infarction were entered into a randomised, double-blind, placebo-controlled comparison of disopyramide phosphate, 150 mg three times a day, and oxprenolol, 40 mg three times a day. When analysed on an intension-to-treat basis there was no significant difference in 6-week mortality between the groups, but patients who were able to continue on the active medications fared better than the patients who had to be withdrawn. The withdrawal rate because of heart failure in patients randomised to receive disopyramide was significantly increased. Patients receiving this agent also showed a reduced number of arrhythmic episodes on 24-h tape recordings but this trend did not achieve statistical significance. The results show that the early use of either oxprenolol or disopyramide phosphate in patients with suspected acute myocardial infarction is unlikely to improve mortality.

Acute Disease↗
PubMed1980

Sulphinpyrazone in acute myocardial infarction: studies on cardiac rhythm and renal function.

Ninety-eight patients with acute myocardial infarction were randomly allocated to receive sulphinpyrazone 200 mg four times daily or placebo on admission to a coronary care unit. Twenty-four-hour electrocardiogram tape recordings showed no significant reduction in serious arrhythmias in the sulphinpyrazone-treated group. In addition to the expected all in serum urate concentration, patients taking sulphinpyrazone showed a persistent increase in their serum urea and creatinine concentrations when compared with those in the placebo groups (p < 0.05 and p < 0.01 respectively). These differences could not be accounted for by differences in the extent and severity of the infarction between the two groups. These results suggest that sulphinpyrazone has no discernible antiarrhythmic effect in acute myocardial infarction.

Arrhythmias, Cardiac↗
PubMed1980

Randomised trial comparing propranolol with atenolol in immediate treatment of suspected myocardial infarction.

The value of beta-blockade for suspected acute myocardial infarction was assessed by determining the six-week and one-year mortality rates in patients started on propranolol, atenolol, or placebo immediately on entry to a coronary care unit. A total of 388 patients entered this double-blind, randomised study, and when analysed on the basis of the initial, intention-to-treat categories there was no significant difference between the three groups in respect of the mortality rate at one year. There was, however, a high withdrawal rate from the trial; the reasons for this illustrate problems of physician compliance and interpretation of data, which are common to all early-entry trials of haemodynamically active agents in acute myocardial infarction.

Adult↗
PubMed1980

Cardiovascular reflexes in patients after myocardial infarction. Effect of long-term treatment with beta-adrenoceptor antagonists.

A double-blind study was made of men who had had a myocardial infarction at least one year previously, and who were being treated with propranolol, atenolol, or placebo. They were compared with age- and sex-matched control subjects. Under resting conditions, there were no differences between the systemic arterial blood pressures, forearm blood flows, or heart rates of the control subjects and the post-infarction patients treated with placebo. The patients, however, showed signs of reduced sympathetic effects on the cardiovascular system when their reflex responses to the Valsalva manoeuvre, lower body negative pressure, and performance of a mental task were assessed. Long-term treatment with propranolol or artenolol had little effect on resting systemic arterial blood pressure or forearm blood flow, but caused a significant reduction in resting heart rate. Differences in the reflex responses of these patients and those on placebo were attributable to the effects of the beta-adrenoceptor antagonists on resting heart rate. These results indicate that post-infarction patients do not have signs of overactivity of autonomic nervous control of the cardiovascular system. Furthermore, long-term treatment of such patients with beta-adrenoceptor antagonists does not impair cardiovascular reflexes.

Adrenergic beta-Antagonists↗
PubMed1980

Importance of age in prehospital and hospital mortality of heart attacks.

Prehospital and hospital fatality rates were calculated for each 10-year age group of 2788 patients transported to hospital with heart attacks. The prehospital fatality rate rose progressively from 4 per cent in the youngest age group to 45 per cent in the oldest. There was no age-related difference between the groups in the interval between the onset of symptoms and the first call for help, and a similar proportion of each group summoned a general practitioner. Among those admitted to hospital there was a progressive rise with age in the proportion eventually found to have had a definite or probable myocardial infarction, and among such patients the hospital fatality rate rose from 8 per cent in the youngest group to 35 per cent in the oldest. There was a progressive rise with age in the symptoms and signs of, and treatment for, heart failure. Reported fatality rates from myocardial infarction can only be interpreted if the ages of the patients are known in detail.

Adult↗
PubMed1979

Verification of smoking history in patients after infarction using urinary nicotine and cotinine measurements.

Urinary concentrations of nicotine and its major metabolite cotinine were measured in volunteers whose smoking habits were known to test the reliability of the measurements as indicators of current smoking. In the non-smokers detectable concentrations were always below the confidence limits set for the method, while in smokers the concentrations were always above these limits. After subjects stopped smoking cotinine appeared in the urine for longer than nicotine and was still detectable at least 36 hours after the last cigarette had been smoked. When this method was used to verify the smoking histories given by patients attending an infarction clinic it was estimated that 46-53% of previous smokers had actually stopped smoking compared with the 63% who said that they had done so. It is suggested that simultaneous assays of urinary nicotine and cotinine may be a useful means of verifying patients' current smoking habits.

Cotinine↗
PubMed1979

Effect of beta-blockers on arrhythmias during six weeks after suspected myocardial infarction.

Twenty-four-hour electrocardiographic tape-recording was used to investigate the incidence of arrhythmias in patients with suspected myocardial infarction who were receiving either propranolol, atenolol, or placebo. Recordings begun within 24 hours after admission to a coronary care unit showed that 76% of patients eventually found to have had a myocardial infarction had ventricular arrhythmias of a type generally regarded as serious, whereas of patients in whom myocardial infarction was not substantiated, only 24% had such arrhythmias. At one and six weeks after admission the incidence of arrhythmias ranged from 25% to 33% irrespective of diagnosis. Of patients monitored at both one and six weeks, however, only 5% had arrhythmias on each occasion. Patients treated with propranolol and atenolol showed a similar incidence of arrhythmias to those taking placebo. There was no difference in the incidence or type of arrhythmias recorded between patients who died and those who were still alive at six weeks.These results confirm that "serious" ventricular arrythmias occur in most patients during the acute phase of myocardial infarction and suggest that they do not constitute an independent risk factor. Beta-blockers showed little evidence of useful antiarrhythmic action in the dosage used, but increasing the dosage in suspected myocardial infarction is not practicable because of the risk of hypotension. The findings raise grave doubts about the value of studying arrhythmias to assess drugs intended to reduce mortality from myocardial infarction.

Arrhythmias, Cardiac↗
PubMed1978

Dexamethasone in acute stroke.

Over 13 months 118 patients admitted to hospital with acute stroke were allocated at random to treatment with either dexamethasone or placebo. At one year there was no significant difference in the numbers of survivors or in the quality of life between the two groups. The results suggest that there is no indication for the routine administration of dexamethasone to a heterogeneous group of patients with stroke.

Acute Disease↗
PubMed1978

Randomised study of six beta-blockers and a thiazide diuretic in essential hypertension.

Atenolol was compared with five other beta-blockers and a thiazide diuretic in a randomised cross-over trial of once-daily treatment of essential hypertension. Atenolol was significantly better at reducing resting and exercise blood pressures at 24 hours than any of the other drugs and had a low incidence of side effects. Both timolol and acebutolol had a significant hypotensive effect at 24 hours and a low incidence of side effects, suggesting that further increases in dosage might be effective and well tolerated. Labetalol proved ineffective when given once daily, and the high incidence of side effects, equalled only by pindolol, would probably prohibit further increases in dosage. Bendrofluazide was equal or superior to all the beta-blockers except atenolol at reducing resting blood pressure, and its cheapness still makes it an agent of first choice in mild or moderate essential hypertension.

Acebutolol↗
PubMed1978

Serum lipid concentrations and blood pressure in obese women.

In 70 obese women no correlation was found between body weight and serum cholesterol or triglyceride concentrations, but there was a significant correlation between weight and blood pressure. Weight reduction by diet or jejunoileal shunt was not accompanied by any significant change in serum lipid concentrations other than the decrease in serum cholesterol expected after intestinal bypass. Twelve months after bypass surgery was carried out on 14 patients, however, both systolic and diastolic blood pressures were significantly reduced and at levels appropriate to the patients' new weights. These results suggest that obesity in women cannot be taken to indicate the presence of hyperlipidaemia and that sustained weight loss may lower blood pressure.

Adolescent↗