Increased plasma free dopamine after treatment with atenolol and oxprenolol in essential hypertension

In 19 men aged 50 with essential hypertension, 18 weeks' treatment with atenolol (n = 9) or oxprenolol (n = 10) increased supine plasma free dopamine concentrations by 78% (p less than 0.05) and 121% (p less than 0.001) respectively. Increments in plasma dopamine were observed in all patients except for one treated with atenolol. Supine peripheral venous adrenaline and noradrenaline concentrations were not influenced by beta-blockade. The mechanism and significance of the present elevation of plasma free dopamine by beta-blockade are unknown. However, increased plasma free dopamine may be involved in the hypotensive effect of chronic beta-adrenergic blockade, both beta-1 selective and non-selective, and may lend further support to decreased dopaminergic activity in essential hypertension.

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.

Increased plasma vasopressin and serum uric acid in the low renin type of essential hypertension

In 22 50-year-old men with long-standing, untreated essential hypertension of the low renin type, venous plasma vasopressin concentrations were about three times those of 15 matched normotensive control subjects (p less than 0.005). These patients also had increased arterial concentrations of noradrenaline and adrenaline (p less than 0.05) but there was no direct association between these two catecholamines and vasopressin. On the other hand, adrenergic beta-receptor blockade with oxprenolol reduced both blood pressure and plasma vasopressin (p less than 0.01) while venous plasma dopamine concentrations significantly increased. In addition, the hypertensives had highly significantly increased serum uric acid (p less than 0.001) that correlated positively with venous vasopressin concentrations (p less than 0.05). According to these data, patients with the volume-sustained low renin type of essential hypertension have increased plasma vasopressin concentrations that probably are inversely related to dopaminergic nervous activity. The data also indicate that increased plasma vasopressin correlates with serum uric acid, most probably through increased tubular reabsorption of this acid.

Controlled clinical study on antihypertensive treatment with a diuretic and methyldopa compared with a beta-blocking agent and hydralazine

Twenty-eight previously untreated patients with essential hypertension were included in a randomized double-blind cross-over study comparing the results of treatment with the established combination of a thiazide and methyldopa (regimen A) with the combination of a beta-receptor blocker and hydralazine (regimen B). Three patients each developed intolerable side-effects on each regimen but they were all treated successfully on the alternative regimen. The remaining 22 patients obtained a significant reduction in BP at rest and during exercise on both treatments, with no significant difference between the two schedules. Heart rate was significantly reduced at rest and during exercise with regimen B, while a significant reduction was also obtained following exercise on regimen A. There was no significant difference between the two regimens as to tolerable side-effects during treatment, which were registered in about 60% of the patients on each scheme. However, 64% of the patients were treated satisfactorily without side-effects on either regimen. It is concluded that the combination of a beta-blocking agent and hydralazine is without obvious advantages compared with the combination of thiazide and methyldopa in obtaining initial BP control in patients with essential hypertension.

[Potential possibilities of using adrenergic beta blockers in chronic heart failure]

The study was undertaken to examine the efficacy of beta-adrenoblockers used in 26 patients with chronic heart failure which had been caused by coronary heart disease in 12 patients, by rheumatic heart disease in 8 patients, by dilated cardiomyopathy in 5 patients, and by chronic myocarditis in 1 patient. beta-Blockers such as oxprenolol, propranolol, and metoprolol were supplemented to the therapy of the patients with chronic heart failure who were resistant to cardiac glycosides, diuretics, and vasodilators. This resulted in functional class improvement by the New York Heart Association from 3.67 +/- 0.1 to 2.29 +/- 0.1. The authors defined the following predictors of the efficacy of beta-blockers in chronic heart failure: duration of the disease, diastolic pressure, cardiac rhythm, and left ventricular ejection fraction and discussed the mechanisms responsible for their positive effect in chronic heart failure.

Elevated serum activity of N-acetyl-beta-glucosaminidase in essential hypertension: diagnostic value and reversal to normal values after antihypertensive therapy

Previous studies have shown that urinary N-acetyl-beta-glucosaminidase (NAG) is elevated in patients with hypertension, even without renal disease. To elucidate the value of measuring NAG, both in urine and serum of hypertensive patients, we measured NAG activity in the serum, plasma, and 24-hour urine by the fluorimetric method in 84 patients with uncomplicated essential hypertension before and after 6 months of effective treatment. NAG activities of these hypertensive patients were compared with those of 102 healthy normotensive subjects and 97 patients with various renal diseases and controlled hypertension. Serum NAG activity was clearly greater in patients with essential hypertension (427 +/- 124 U/mL) than in normotensive subjects (380 +/- 109 U/mL) or patients with renal disorders (393 +/- 115 U/mL) (P less than or equal to 0.004). The greater was the diastolic pressure in the hypertensive group, the greater was serum NAG activity (r = +0.30, P = 0.004). Hypertensive patients with high serum NAG activity were further characterized by a more exaggerated increase in systolic pressure (34 +/- 16 v 25 +/- 15 mm Hg, P = 0.051) and total peripheral resistance (19% +/- 18% v 12% +/- 13%, P = 0.042) in response to the cold pressor test and by a greater increase in systolic pressure (56 +/- 15 v 45 +/- 13 mm Hg, P = 0.009) and diastolic pressure (11 +/- 7 v 6 +/- 9, P = 0.043) in response to bicycle exercise testing than the group with low serum NAG activity. In contrast, urinary NAG activity tended to be only slightly higher in patients with essential hypertension than in the normotensive control group (33 +/- 31 v 23 +/- 29 U/mg creatinine [cr], P = 0.062), whereas patients with renal diseases had clearly increased urinary NAG activity (87 +/- 105 U/mg cr) (P less than 0.001). Following effective antihypertensive therapy, serum NAG activity decreased in patients with essential hypertension to values of normotensive control subjects (from 427 +/- 124 U/mL to 386 +/- 106 U/mL, P less than 0.01). A significant decrease in serum NAG activity was observed in patients with both initially high as well as low pretreatment serum NAG activities (P less than 0.001 and P less than 0.02, respectively). Urinary NAG activity overall was unchanged by antihypertensive treatment. We conclude that in patients with mild essential hypertension, serum NAG activity was already elevated (whereas urinary NAG activity was not) and was normalized by effective antihypertensive treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

[Nifedipine and gingival hypertrophy]

Nifedipine-induced gingival hypertrophy is a rare side effect reported by the producers of this drug but, surely, not well known in all its aspects. In the present case report this pathology is studied in a patient treated with nifedipine for 30 months for cardiac angina, analyzing the histologic features, the therapy plain conducted for the hypertrophy and the most important pathogenetic theories formulated till now.

[Electrocardiographic and echocardiographic changes during antihypertensive therapy]

To investigate the changes of electrocardiographic and echocardiographic indexes of left ventricular hypertrophy (LVH) during antihypertensive therapy, 100 hypertensive patients, mean age 46 years, were studied in pretreatment condition and during 12 months of antihypertensive therapy. In pretreatment condition, 83 patients showed LVH by echocardiography (echo; left ventricular mass index greater than 130 g/m2) and 30 patients had LVH by electrocardiography (ECG) (Sokolow index greater than 35 mm). In comparison to echo index of LVH, Sokolow index showed a sensibility of 34% and a specificity of 88%. Both LV mass echo index and ECG index significantly decreased after 3 months but in different way. LV mass index mainly decreased after 12 months, whereas Sokolow index particularly decreased after 6 months, with no further changes in the subsequent months. After 12 months of therapy, the LV mass echo index normalized in 19% of the patients (16/83) and Sokolow index normalized in 57% (17/30). ECG sensibility and specificity, in comparison to LV mass echo, was 20% and 100%, respectively. Thus, ECG appears less sensitive than echo in the detection of LVH. During antihypertensive therapy ECG index of LVH normalized more precociously and to a greater extent than the echo index. However, the normalization of LVH by ECG does not necessarily mean that a complete anatomic regression of LVH has occurred.

[Changes in lipid fractions of blood during the treatment of hypertension with prazosin and trasicor]

The paper deals with the study into the benefits of prazosin and trasicor used in arterial hypertension. Their effects on the blood lipid composition were evaluated. With prazosin, the steady antihypertensive effect was reached in 81.0%, whereas with trasicor, it was attained in 46%. When prazosin was given, total cholesterol and triglycerides were statistically significantly decreased by 6.8 and 14.8%, respectively, while high density lipoproteins was increased by 9.1%. When trasicor was administered, no changes were observed in the spectrum of serum lipids. Thus, prazosin is effective in correcting two major risk factors for coronary heart disease, namely arterial hypertension and hyperlipoproteinemia, thereby reducing a risk for coronary heart disease.

Importance of quantitative analysis of ventricular arrhythmias for predicting the prognosis in low-risk postmyocardial infarction patients. European Infarction Study Group

In 378 placebo patients enrolled in the European Infarction Study (EIS), a secondary prevention study after acute myocardial infarction, 24-h baseline Holter monitoring was done 14 to 31 days after MI, and the relationship of electrical (ventricular arrhythmias) and mechanical (clinical signs of ventricular dysfunction) risk factors was analysed on the basis of mortality during the subsequent 2 years of follow-up. There was a rather low overall 2-year mortality rate of 6.9%. Consecutive arrhythmias (ventricular pairs and runs of ventricular premature beats) and left-ventricular dysfunction alone were associated with a low mortality of 4.0% and 3.6%, respectively. However, the combination of both defined a high-risk group characterized by a 2-year mortality rate of 16.7%. Additionally, the risk of dying was dependent on the frequency of consecutive arrhythmias: 22.2% of the patients with greater than 10 ventricular pairs per day died during the follow-up period in contrast to 9.9% of those with only 1-10 ventricular pairs per day. Thus, only the combination of electrical and mechanical risk factors, and especially the frequency of consecutive VPB, is helpful in identifying a subgroup of postMI patients with poor clinical outcome. An intervention study should restrict itself to this risk population only.

Efficacy and tolerability of long term oxprenolol and chlorthalidone singly and in combination in hypertensive blacks

Sixty two black patients who had confirmed but untreated hypertension participated in a double blind clinical trial of the efficacy and tolerability of slow-release oxprenolol in a daily dose of 160 mg initially and 320 mg subsequently versus chlorthalidone 50 mg daily. Thereafter, a combination of oxprenolol with chlorthalidone in an initial dose of 160 mg and 25 mg and a subsequent dose of 320 mg and 50 mg, respectively, was administered and the effects compared with those of the same drugs given singly. The trial lasted for 3 years, but each participant took active medication for 1 year. Oxprenolol as monotherapy had no effect on the blood pressure, irrespective of the dose. Chlorthalidone as monotherapy produced a significant fall in blood pressure (p less than 0.01). Combining the 2 drugs enhanced their blood pressure lowering effects (p less than 0.001). Oxprenolol as monotherapy and as part of combination therapy was well tolerated by all patients. Chlorthalidone as monotherapy was well tolerated by most patients while a fraction of the patients developed biochemical derangements. These results confirm the findings that a beta-blocker alone may be ineffective in lowering blood pressure in hypertensive blacks. The results also show that the efficacy and tolerability of a beta-blocker and a diuretic are enhanced by their combined administration. Finally, the results show that increasing the dose of a beta-blocker or a diuretic does not produce a further increase in its blood pressure lowering effect.

A randomized comparison of early with conservative use of antihypertensive drugs in the management of pregnancy-induced hypertension

Two treatment strategies were compared in 155 women with pregnancy-induced hypertension who were also given comprehensive non-pharmacological care. The mean gestation at entry was 28 weeks. As long as the diastolic blood pressure (DBP) remained below 106 mmHg, oxprenolol, or oxprenolol plus dihydralazine, were given to the early treatment group, and matching placebos to the control group. Open antihypertensive treatment was provided for patients whose DBP rose above 105 mmHg. Proteinuria occurred in seven women in each group. In the early treatment group, 13 of the 78 women were delivered by caesarean section; the corresponding numbers in the control group were 27 of 76 (17 vs 36%, 95% confidence interval (CI) of difference: 5-33%); the sections included seven and 16 in the early treatment and control groups, respectively, for severe hypertension and/or fetal distress. There were five perinatal deaths, two in the early treatment group and three in the control group. Early treatment did not influence gestational age at birth or birthweight. Respiratory distress syndrome occurred in four infants in the early treated group and in 10 in the control group; 14 infants in the former group and 26 in the latter were in hospital for more than 10 days (18 vs 35%; 95% CI of difference 4-32%). These results indicate that early antihypertensive treatment with oxprenolol is safe for the fetus and newborn in pregnancy-induced hypertension, but has no advantage over non-pharmacological care in terms of fetal growth. However, it may prevent acute hypertension in late pregnancy and associated fetal distress, and thus reduce the number of caesarean sections.

Beta-blocking agent facilitating the spontaneous passage of ureteral stones

Based on data from neurophysiological studies, the author checked the action of a beta-blocking agent facilitating spontaneous stone passage from the ureter. Experience has shown that, compared with the control group, the beta-receptor-blocking agents proved to be useful in the facilitation of a spontaneous discharge of stones located in the lower part of the ureter.

Efficacy of four antihypertensive drugs (clonidine, enalapril, nitrendipine, oxprenolol) on stress blood pressure

The impact of 4 antihypertensive drug regimens on blood pressure (BP) during everyday life stress and on BP during experimental stress in the laboratory was examined in an open clinical study. Sixty middle-aged men with mild-to-moderate essential hypertension never previously treated were treated either with low-dose clonidine (n = 10), oxprenolol (n = 20), nitrendipine (n = 20) or enalapril (n = 10). Before therapy, all 4 groups did not differ in age, weight, degree of obesity, BP at work site and casual BP measured in the outpatient clinic. After 6 months of effective therapy (casual BP within the normotensive range), casual diastolic BP was identical among the 4 groups, whereas systolic BP was lower in patients treated with clonidine or oxprenolol than in those who received enalapril. A disparate pattern of antihypertensive efficacy among the 4 groups emerged when stress BP was compared, with average ambulatory BP higher in patients receiving clonidine or enalapril than in those who had oxprenolol or nitrendipine. During ambulatory BP monitoring, patients treated with oxprenolol had the lowest level at each level of physical activity and self-reported emotional arousal. During bicycle exercise, patients receiving clonidine had the highest increase in systolic BP and those administered oxprenolol the lowest, whereas the BP response during mental stress was similar among all 4 therapeutic groups. The analysis of the hemodynamic response pattern during mental stress unmasked further disparities. Oxprenolol provoked an abnormal hemodynamic response during mental stress tests (increase in total peripheral resistance), whereas nitrendipine and enalapril preserved the physiological hemodynamic profile (decrease of total peripheral resistance).(ABSTRACT TRUNCATED AT 250 WORDS)

Disparities in blood pressure control under various antihypertensive regimens

Ambulatory blood pressure recordings and stress blood pressures during exercise were compared among hypertensive patients effectively treated with oxprenolol, nitrendipine, enalapril or low-dose clonidine. After 6 months of therapy, the means of blood pressure at rest and casual diastolic pressure were nearly identical among the four therapeutic groups. Although all pressures fell to within the normotensive range, casual systolic pressures were lower in patients treated with sympatholytic agents than in those taking enalapril. In contrast, average ambulatory blood pressure was less controlled in patients given clonidine or enalapril than in those given oxprenolol or nitrendipine. During physical stress patients taking clonidine showed the highest stress blood pressures and those taking oxprenolol the lowest pressures. The study demonstrated that although blood pressure was reduced to within the normotensive range in all four therapeutic groups, analysis of values of ambulatory blood pressure and stress blood pressure during physical activity showed a disparate pattern of antihypertensive efficacy.

Effects of chlorthalidone, oxprenolol, and their combination in hypertensive blacks: a randomized double-blind crossover study

One hundred twenty black patients with mild to moderate essential hypertension participated in a double-blind placebo-controlled crossover study of the efficacy and tolerability of slow release oxprenolol versus chlorthalidone singly and in combination. Oxprenolol as monotherapy produced no effect on blood pressure as compared with placebo even after doubling the dose. Chlorthalidone as monotherapy produced a significant decrease in blood pressure (p less than 0.01). Combining oxprenolol with chlorthalidone yielded hypotensive effects in excess of those of either of the components given singly. Oxprenolol produced a significant decrease in plasma renin activity (PRA) whereas chlorthalidone produced a significant increase in PRA. These results indicate that a beta-blocking agent alone is ineffective in lowering blood pressure in hypertensive blacks, even when the dose is high. Oxprenolol may increase the hypotensive effect of chlorthalidone by counteracting the hypokalemic effect of the diuretic and by attenuating the diuretic-induced increase in plasma renin activity.

[Type A behavior and psychological characteristics of hypertensive patients undergoing antihypertensive treatment]

The aim of this study was to evaluate the presence of "type A" behaviour and possible psychological distress in 373 hypertensive patients. One-hundred and ninety-five males, 56.2 +/- 6.2 years old and one-hundred and seventy-eight females, 57.1 +/- 6.2 years old, coming from the IPPPSH and still under double-blind treatment with or without a beta-blocker (oxprenolol 160 mg SR), were studied by means of the Jenkins Activity Survey form C and several tests from the Cognitive Behavioural Assessment Battery (CBA-2.0). Seventy-four point eight percent of the patients showed a "type A" pattern, and 25.5% were in the extreme predictive interval for coronary heart disease according to WCGS. "Type A" pattern was not influenced by variables such as age, sex, education, job or previous pharmacological treatment. The patients studied did not show any particular psychological distress at the psychometric evaluation. However, special social and cultural characteristics and different therapies influenced some symptoms, such as anxiety, depression and somatic lamentation. According to this study: "type A" behaviour seems to be a steady feature of the hypertensive patient; furthermore, it seems to be due to a "biological imprinting" which can be considered a cause of hypertension; psychological distress depends on a particular set of environmental stimuli. In the first case an accurate prevention is needed while, in the second case adequate pharmacological and/or psychological therapies are needed.

Concentration-effect relationships for oxprenolol in patients with essential hypertension

1. Plasma drug concentrations, and heart rate and blood pressure responses to exercise at a predetermined load were examined in twelve hypertensive patients following single and repeated doses of oxprenolol administered once daily as oral osmotic drug delivery systems (10/170 and 16/260 oxprenolol OROS). 2. Plasma oxprenolol concentration profiles after each preparation were consistent with the criteria for sustained drug release. Levels immediately after exercise were significantly higher than those prior to exercise (P less than 0.001), but differences were slight. 3. Both OROS drug forms reduced exercise heart rate for 24 h after single and repeated doses; effects were greater for 16/260 OROS than for 10/170 OROS. Significant reductions in post-exercise systolic BP were observed 24 h after drug administration and after repeated doses there was little difference between the preparations. Effects on diastolic BP after exercise were slight. 4. The relationship between plasma oxprenolol concentrations and exercise heart rates fitted an exponential mathematical model which makes allowance for inter-individual variability. No such kinetic-dynamic relationship could be defined for post-exercise systolic or diastolic BP.

Myocardial ischemia in untreated hypertensive patients: effect of a single small oral dose of a beta-adrenergic blocking agent

In a non-double-blind, prospective, randomized study, the intra-operative electrocardiograms of 128 mildly hypertensive surgical patients were examined in order to determine the incidence of myocardial ischemia during anesthesia. No patient had been receiving chronic antihypertensive therapy prior to the study, but a single small oral dose of a beta-adrenergic blocking agent (labetalol, atenolol, or oxprenolol) was given to 89 of them along with premedication. Forty-four per cent of the untreated control patients and 61% of the patients pretreated with a beta-adrenergic blocking agent had normal preoperative electrocardiograms and no risk factors for coronary artery disease other than hypertension (this difference between groups was not statistically significant). During tracheal intubation and/or emergence from anesthesia, a brief, self-limited episode of myocardial ischemia was detected in 11 of 39 untreated control patients, and in two of 89 patients pretreated with a beta-adrenergic blocking agent (P less than 0.001). Tachycardia always accompanied the ischemic events, but a conspicuous increase in blood pressure did not. The authors conclude that mild hypertension, when untreated prior to the induction of anesthesia, is associated with a high incidence of myocardial ischemia; and that a single small oral dose of a beta-adrenergic blocking agent, given with pre-medication, can significantly reduce that risk.

Crossover design to test antihypertensive drugs with self-recorded blood pressure

In a double-blind, within-patient study, blood pressure was measured at regular intervals at the clinic by the physician and each day at home by the patient. Both methods of blood pressure measurement demonstrated an antihypertensive effect of the diuretics chlorthalidone (25 mg) and triamterene (50 mg) and the beta-blocker oxprenolol (160 mg) and the greater efficacy of the combination of the two therapies. During placebo, as well as during active treatment, blood pressure values were higher at the clinic than at home, except when the patients were taking the beta-blocker, which minimized the arousal response during blood pressure measurements in the clinic. With 2-week treatment periods, separated by 2 weeks of placebo administration, blood pressure returned toward its initial level after each of the three treatments and none of the carryover effects was significant at the 5% level. This methodology was intended to make it possible to demonstrate in 27 patients at the clinic and in 20 patients with measurements made at home, at the usual statistical risks (alpha = 5%, beta = 10%), a fall of 5 mm Hg in diastolic blood pressure in comparison with a placebo. Moreover, at the end of this 3-month follow-up, each patient could continue to receive the treatment that was the most effective and the best tolerated. In conclusion, the use of a within-patient trial design, with a 15-day washout period between active treatments and careful recording of blood pressure values, can minimize the number of patients included in hypertension trials and offer to each patient the possibility of individualization of treatment.

Impact of smoking on heart attacks, strokes, blood pressure control, drug dose, and quality of life aspects in the International Prospective Primary Prevention Study in Hypertension

Effects of smoking are highlighted in a posthoc analysis of this randomized, double-blind International Prospective Primary Prevention Study in Hypertension (IPPPSH). At the time of entry, 37% of the men and 23% of the women were smoking cigarettes, and only 537 patients changed their smoking status during the trial. In men and women, smoking doubled cardiac and cerebrovascular event rates. Nonsmoking men had fewer myocardial infarctions and sudden deaths when treated with oxprenolol. Smoking status did not affect in-study blood pressure control, the type of drugs, or the combinations used, but smokers were given higher doses of oxprenolol. For a given blood pressure during antihypertensive treatment, rates for cardiac and cerebrovascular events were higher in smokers. Heart rates were higher in both oxprenolol and non-beta-blocker-treated smokers. Smoking dose dependently increased hematocrit level. Among physician-elicited symptoms, dyspnea and cold extremities were more frequent in smokers, whereas dyspnea, headaches, impotence, dizziness, and anxiety states were common, with unsatisfactory blood pressure control (diastolic blood pressure greater than 95 mm Hg). Quality of life may be more jeopardized by smoking, poor blood pressure control, or diuretic use than by beta-blocker-based therapy. In the IPPPSH, the patient who smoked had double the cardiovascular complication rates without cardiac benefit from the beta-blocker despite higher doses given; the higher heart rate and hematocrit level may have been contributing factors.

Comparison of oxprenolol vs methyldopa as second-line antihypertensive agents in the elderly

Direct within-patient comparisons of the effects of centrally acting sympathetic inhibitors and beta-blockers on blood pressure (BP) of the elderly have not been done. In the present study, 32 elderly hypertensive patients were treated with a diuretic. Methyldopa (500 mg/d) (16 patients, subgroup A) or slow-release oxprenolol (80 mg/d) (subgroup B) was added as a second-step antihypertensive agent for a period of eight weeks, after which the second-step agents were switched, respectively, for another period of eight weeks. In subgroup A the supine BP dropped from 193/99 to 169/93 mm Hg and the standing BP from 183/100 to 163/92 mm Hg, whereas in subgroup B the supine BP fell from 190/103 to 182/97 mm Hg and the standing BP from 187/101 to 172/95 mm Hg. After switching the drugs, the respective BP values were 177/91 and 170/95 mm Hg and 170/90 and 156/89 mm Hg. In the doses given, methyldopa therapy is more effective than oxprenolol therapy in lowering the BP of elderly hypertensive patients.

Evaluation of two oxprenolol oral osmotic (OROS) delivery systems in patients with essential hypertension

The effects of two oxprenolol oral osmotic (OROS) delivery systems on heart rate and blood pressure before and during recovery from exercise at a predetermined load were examined in twelve patients with hypertension previously responding to beta-blocker monotherapy. Haemodynamic responses were attenuated during the 24 h after single and repeated (15 days') once daily administrations of 10/170 and 16/260 oxprenolol OROS. At 24 h after repeated doses, compared to placebo there were significant reductions in resting blood pressure and in heart rate immediately following exercise. Attenuation of heart rate after exercise was dose related but differences between the systems with respect to resting heart rate and blood pressure were inconsistent. Antihypertensive responses after repeated doses were greater than those after single doses. However, reductions in resting and exercise heart rates were consistently less on chronic therapy. This may reflect enhanced expression of the partial agonist activity of oxprenolol due to altered receptor sensitivity after prolonged beta-blockade. The plasma oxprenolol profiles after both systems indicated slow absorption and substantial concentrations were apparent 24 h after drug administration. These observations suggest that both oxprenolol OROS systems display sustained drug release and on once daily dosing provide 24 h beta-blockade and control of blood pressure at rest and following exercise.

Beta-blockade reverses regional dysfunction in ischemic myocardium

To determine the protective effect of oxprenolol-induced beta-blockade on the compromised myocardium (critical constriction of the left anterior descending coronary artery) against the adverse effect of high concentrations of halothane, halothane dose-response curves were obtained in six dogs in each of three phases: preconstriction (control), critical constriction, and critical constriction with the addition of 0.3 mg/kg intravenous oxprenolol. The extent of depression of ventricular function was essentially the same in the three phases. However, at high halothane concentrations (2.0% inspired), the depression of systolic shortening in the compromised segment was significantly minimized after oxprenolol so that shortening was 10.2% +/- 1.8 instead of 6.5% +/- 1.4 (P less than 0.05); moreover the large increase in postsystolic shortening observed during critical constriction was abolished after oxprenolol. This suggests a protective effect of oxprenolol on regional myocardial function in the presence of critical constriction, possibly by an effect on myocardial metabolism or endocardial blood flow.

Electrocardiographic changes during antihypertensive therapy in the International Prospective Primary Prevention Study in Hypertension

In the International Prospective Primary Prevention Study in Hypertension, electrocardiographic changes before and during 3- to 5-year antihypertensive treatment were investigated in a cohort of 5819 men and women aged 40 to 64 years with entry diastolic blood pressures of 100 to 125 mm Hg. They were randomly allocated to treatment regimens that either included or excluded the slow-release beta-blocker oxprenolol. Electrocardiograms (ECGs) were assessed using the Minnesota Code and assigned to groups of normal ECGs or ECGs with pressure-related, ischemic, "intermediate," or "other" abnormalities. Antihypertensive treatment was associated with a decrease (mainly in men) of pressure-related and (mainly in women) of intermediate abnormalities. Ischemic abnormalities increased, particularly in men. Inclusion of the beta-blocker resulted in a greater reduction in intermediate abnormalities and in a lesser increase in ischemic abnormalities. Better blood pressure control was associated with a lesser increase in ischemic abnormalities and in a regression of pressure-related abnormalities. The presence of ST segment depression and of a complete left bundle branch block in the entry ECG was associated with a significant risk for sudden death and myocardial infarction. Optimal blood pressure control prevents pressure-induced cardiac target organ damage and, hence, heart failure, and may delay the progression of ischemic abnormalities. This tallies with the lower critical cardiac event rate associated with lower blood pressure that was observed in the same study.

Disparate effects of initial antihypertensive therapy on well-being

We investigated the effects of baseline antihypertensive therapy on well-being in a randomized single-blind study in patients with recently diagnosed essential hypertension (WHO stage I). Sixty middle-aged men were treated either with a beta-blocker (oxprenolol) or a calcium-entry blocker (nitrendipine). Well-being was assessed by questionnaires on mood and anxiety. Both regimens were equally effective at lowering blood pressure. Differences in mood were found between patients on the beta-blocker and those on the calcium-entry blocker in the first week of therapy. Responders and non-responders to calcium-entry blocker did not differ in mood and anxiety. Non-responders to beta-blocker had a less balanced mood after the onset of therapy than patients effectively treated with this regimen over 9 months. These results suggest that the impact of therapy on well-being should be carefully assessed during antihypertensive therapy, and might be considered a major determinant of patients' compliance.

Disparate hemodynamic responses to mental challenge after antihypertensive therapy with beta blockers and calcium entry blockers

The hemodynamic response to mental challenge was studied in 40 male outpatients with mild essential hypertension. The patients were treated randomly either with a beta adrenoreceptor blocker (oxprenolol) or with a calcium entry blocker (nitrendipine). Cardiovascular reactivity was evaluated with two different mental arithmetic tasks before and six months after treatment by continuously measuring systolic and diastolic pressure (ultrasonic Doppler device), heart rate (electrocardiography), and stoke volume (impedance cardiography). Patients in both treatment groups had equal decreases in arterial pressure and the same pressures at rest. In patients receiving calcium entry blockers, mental challenge provoked an increase in stroke volume and a decrease in total peripheral resistance similar to results in the pretreatment phase. In contrast, beta adrenoreceptor blockade reversed the hemodynamic response pattern to a distinct decrease in stroke volume (p less than or equal to 0.05) and an increase in total peripheral resistance (p less than or equal to 0.05). In addition, an attenuated heart rate response (p less than or equal to 0.01) and a larger increase in diastolic pressure (p less than or equal to 0.01) were found in the beta blocker group compared with the calcium entry blocker group. Although beta blockers and calcium blockers produce equal decreases in arterial pressure, beta blockers evoke an abnormal hemodynamic response to mental challenge, whereas calcium entry blockers preserve the physiologic reactivity pattern of the untreated state.

Evaluation of oxprenolol slow release and osmotic release by exercise testing and ambulatory electrocardiographic monitoring in patients with chronic stable angina pectoris

We have treated eleven patients with chronic stable angina pectoris with slow-release oxprenolol (160 mg and 320 mg) in a double-blind crossover study and evaluated its efficacy objectively by exercise testing between 180 and 240 min after dosing. The mean exercise time increased significantly from 6.2 min on placebo to 7.2 min and 7.3 min on oxprenolol 160 mg and 320 mg respectively. No overall beneficial effects could be demonstrated for the higher dose. A further 20 patients received slow release oxprenolol 160 mg and 10/170 mg "Oros" (osmotic release) oxprenolol in a double-blind crossover study using exercise testing and ambulatory electrocardiographic monitoring at 21-23 h after dosing. The mean exercise time increased significantly from 7.0 min on placebo to 8.3 min on slow-release oxprenolol and to 8.1 min on "Oros" oxprenolol. The effects of the 2 treatments on exercise and ambulatory heart rates were comparable. Two patients were withdrawn during the double-blind treatment period while receiving oxprenolol slow-release, one because of unstable angina and another because of throbbing headache. These findings confirm that slow-release oxprenolol is effective in treating chronic stable angina pectoris at the 160-mg dose. "Oros" oxprenolol 10/170 mg has a profile of action closely similar to but without any additional benefit over slow-release oxprenolol 160 mg.

Antihypertensive effects of 12 beta adrenoceptor antagonists in conscious spontaneously hypertensive rats: relationship to changes in plasma renin activity, heart rate and sympathetic nerve function

Twelve beta adrenoceptor antagonists were examined for their effects on mean blood pressure (MBP), heart rate (HR), plasma renin activity (PRA) and sympathetic nerve function in spontaneously hypertensive rats (SHR). The selected drugs included cardioselective agents (acebutolol, atenolol and metoprolol), agents with intrinsic sympathomimetic activity (oxprenolol, acebutolol, alprenolol and pindolol) and agents with local anesthetic activity (propranolol, oxprenolol, acebutolol, alprenolol and labetalol). All 12 beta adrenoceptor antagonists, administered once daily for 4 days (30 mg/kg p.o.), significantly decreased MBP of SHR. This reduction in MBP was dissociable from both reductions in HR as well as peripheral beta adrenoceptor blockade. In addition, the onset of MBP reduction was slower than the onset of beta adrenoceptor blockade and became greater with duration of treatment. PRA activity was significantly and markedly reduced by both bunolol and metoprolol shortly after dosing at a time when HR was significantly reduced but MBP was not. Conversely, at a time when MBP was significantly reduced by both bunolol and metoprolol, PRA and HR were found to be normal. The changes in HR and PRA were correlated with peripheral beta adrenoceptor blockade but changes in MBP were not. Bunolol, metoprolol and propranolol had no consistent inhibitory effect on pressor responses to nerve stimulation in pithed SHR, although positive chronotropic responses to norepinephrine, tyramine, dimethylphenylpiperazinium and angiotensin I and II were significantly and markedly reduced. It is concluded that beta adrenoceptor antagonists, as a class, reduce MBP of conscious SHR, provided that sufficient time is allowed for this observation to occur. Furthermore, the reduction in MBP caused by beta adrenoceptor antagonists is unrelated to acute beta adrenoceptor blockade, changes in HR, reductions in PRA or inhibition of sympathetic nerve function. Finally, cardioselectivity, intrinsic sympathomimetric activity and local anesthetic activity are not required for the antihypertensive activity of these agents.

Hydrochlorothiazide and triamterene with sustained-release oxprenolol in the treatment of hypertension

A single-blind, three-way Latin square crossover study without wash-out periods was performed in a general practice. Thirty moderately hypertensive patients were studied to compare the antihypertensive effect of 160 mg sustained-release oxprenolol once daily, 25 mg hydrochlorothiazide/50 mg triamterene once daily or a combination of the two preparations once daily, each treatment being given for 1 month. Blood pressure control was significantly better with the combination than with either agent used separately. Pulse rates, as expected, were lower when sustained-release oxprenolol was taken either alone or in the combination. Adverse events led to withdrawal in 1 patient only. Otherwise, all treatments were well tolerated and compliance was excellent. Renal function tests indicated a slight increase in creatinine, urate and urea levels after the treatments which included hydrochlorothiazide compared with oxprenolol alone, although the results were of no clinical significance.

Interference by sulphinpyrazone with the antihypertensive effects of oxprenolol

The interfering effect of sulphinpyrazone, a uricosuric agent which reduces the activity of cyclo-oxygenase, with the antihypertensive activity of oxprenolol, a non-cardioselective beta-blocker with sympathomimetic activity, has been evaluated. Ten patients with primary arterial hypertension of mild to moderate degree entered a randomized double-blind cross-over study versus placebo. They were given oxprenolol + placebo or oxprenolol + sulphinpyrazone for 15 days, and then the treatments were crossed-over for a further 15 days. Oxprenolol significantly reduced blood pressure (161 +/- 3/101 +/- 1 vs 149 +/- 4/96 +/- 2 mmHg) and heart rate (72 +/- 3 vs 66 +/- 3 beats/min). During administration of the combination with sulphinpyrazone the blood pressure increased to its pretreatment level (156 +/- 5/101 +/- 2 mmHg). The effect of oxprenolol on heart rate was not influenced by the combined treatment (67 +/- 6 beats/min). The results may be explained by 1) sulphinpyrazone-induced inhibition of prostaglandin synthesis, which could interfere with the antihypertensive activity of oxprenolol, or 2) sulphinpyrazone-induced acceleration of the metabolism of oxprenolol.

The development of reliable compliance tests for antihypertensive drugs

Many tests for measuring compliance have been proposed, but in most cases compliance rates have been determined without taking into account the factors influencing the interval during which a drug can be detected by a qualitative test after having been taken by the patient. The drug half-life, often used for determining the time at which the sample is collected, is inadequate for obtaining conclusive test results. A procedure is described for the determination of urine collection intervals during which reliable information on compliance can be obtained, using oxprenolol, hydrochlorothiazide, and pindolol as examples.

Myocardial infarctions and cerebrovascular accidents in relation to blood pressure control. The IPPPSH Collaborative Group

The International Prospective Primary Prevention Study in Hypertension (IPPPSH) was a long-term clinical trial designed to examine the effects of treatment on hypertension. It shows that in a population who at entry to the study had diastolic blood pressures of 100-125 mmHg, failure to achieve blood pressure control increases the risk of sudden death and myocardial infarction as well as stroke in both sexes and emphasizes the need to control blood pressure on a long-term basis. The absolute cardiac risk reduction associated with pressure control is greater for men than women below achieved diastolic pressures of 101-105 mmHg.

Predictors of blood pressure increases after withdrawal of antihypertensive therapy

We examined possible predictors of the recurrence of high blood pressure (BP) in patients who remained normotensive after withdrawal of drug therapy. Thirty untreated male patients with WHO stage I essential hypertension (mean age 43 +/- 6 years) were randomly allocated to oxprenolol or nitrendipine groups. Before therapy, BP at rest, during mental arithmetic (MA) and during the cold pressor (CP) test was assessed. After 6 months of effective monotherapy, all drugs were withdrawn and casual BP was followed up for 5 months. Two weeks after cessation of therapy 26% were hypertensive again, after 4 weeks 28%, after 12 weeks 48% and after 21 weeks 74%. The two therapeutic groups did not differ in their BP increase after discontinuation of therapy. Predictors for the return of high BP were age, pretreatment BP, systolic and diastolic BP increase to the CP test. Analyses of covariance for age and pretreatment BP confirmed that reactivity to the CP test was a predictor of the return of hypertension.

Effect of oxprenolol on ventricular arrhythmias: the European Infarction Study experience

In 736 patients, 24 hour electrocardiographic recordings were performed 14 to 36 days after acute myocardial infarction before the start of randomized treatment with 320 mg of slow release oxprenolol (n = 358) or placebo (n = 378). Follow-up 24 hour electrocardiographic recordings were obtained 5 to 12 days (median 10) and 3, 6 and 12 months after the first administration of the study medication. Oxprenolol-treated patients had a significantly lower daytime heart rate as compared with the placebo group, whereas no difference was found at night. At baseline, 22.1% of the patients allocated to oxprenolol treatment and 29.6% of the placebo group had more than 30 ventricular extrasystoles in 1 hour at least once during 24 hour monitoring; multiform ventricular extrasystoles were present in 58.4 and 62.7%, ventricular couplets in 29.6 and 33.9% and ventricular tachycardia (3 or more consecutive ventricular extrasystoles) in 21.5 and 20.9% of the oxprenolol-treated and placebo-treated patients, respectively. During the 1 year follow-up period, the prevalence of these arrhythmias did not change significantly in either treatment group. There was a trend toward a reduction in the daytime frequency of ventricular couplets in the oxprenolol group. After 3 and 6 months, only multiform ventricular extrasystoles were significantly less frequent in the oxprenolol group than in the placebo group (47.4 and 42.7% versus 59.7 and 57.9%, respectively). Twelve months after the acute event, however, multiform ventricular extrasystole frequency was the same in both groups of patients (52.1 versus 51.0%, respectively). Thus, oxprenolol had a weak suppressant effect on ventricular tachyarrhythmias in survivors of myocardial infarction.

Angiotensin converting enzyme inhibitors and quality of life: the European trial

Two prospective multi-centre randomized trials were initiated to compare the relative efficacy and influence on quality of life of captopril, alone or in combination with hydrochlorothiazide, against either methyldopa, alone or in combination with hydrochlorothiazide, or oxprenolol in combination with chlorothalidone. The complaint rate, activity index and psychiatric morbidity were evaluated as indices of quality of life. Captopril was associated with a significantly (P less than 0.05) greater reduction in complaint rate compared with methyldopa and a tendency for less symptoms of depression compared with oxprenolol (P = 0.06), the latter drug being associated with an increase in depression scores. The trends in quality of life indices in the captopril-treated patients would suggest the need for double-blind placebo-controlled trials to investigate these apparent benefits.

A comparison of single doses of bucindolol and oxprenolol in hypertensive patients

Single doses of bucindolol 50, 100 and 200 mg were compared to placebo and single doses of oxprenolol 40, 80 and 160 mg in seven patients with mild hypertension, in a double-blind randomized study. Both bucindolol and oxprenolol inhibited exercise induced tachycardia. The mean maximum inhibition of exercise heart rate was similar after each dose of both drugs (20%, P less than 0.001). Bucindolol produced a significantly greater reduction in blood pressure than either oxprenolol or placebo. This was most apparent in standing systolic and diastolic and post-exercise systolic blood pressures between 1 and 2 h after dosing and was dose-related. All seven patients experienced adverse effects related to hypotension within the first 2 h after ingestion of bucindolol 200 mg. Plasma concentrations of oxprenolol, bucindolol or 5-hydroxy-bucindolol, sampled 2 h after dosing, could not be related to either the changes in blood pressure or to the occurrence of symptoms. The results emphasise the need for careful dose-finding of new drugs prior to their more widespread evaluation in phase 3 studies.

Antihypertensive treatment in pregnancy: analysis of different responses to oxprenolol and methyldopa

One hundred and eighty three hypertensive pregnant women were randomly assigned to antihypertensive treatment with oxprenolol (96 women) or methyldopa (87 women). Control of hypertension was equivalent in both treatment groups, and in 64 (35%) cases hydralazine had to be added to the treatment to achieve the therapeutic goal (diastolic blood pressure below 85 mm Hg). Five perinatal deaths occurred, one in the oxprenolol group and four in the methyldopa group. Detailed analysis confirmed a previous report of greater fetal growth in the group treated with oxprenolol; this trend was present regardless of severity of hypertension and parity. With increasing duration of treatment the differences between the two groups diminished, and there was no difference after 10 weeks of treatment, a finding that may explain some of the reported discrepancies among therapeutic studies. As hypertension in pregnancy may pursue an accelerated course, necessitating urgent delivery, and there is no satisfactory method of predicting the duration of treatment in individual patients fetal benefit is most likely to be achieved by treatment with oxprenolol, provided that there is no maternal contraindication to treatment with beta blockers.

Cardiovascular risk and risk factors in a randomized trial of treatment based on the beta-blocker oxprenolol: the International Prospective Primary Prevention Study in Hypertension (IPPPSH). The IPPPSH Collaborative Group

Myocardial infarction, sudden cardiac death, cerebrovascular accidents, blood pressure control and treatment tolerability were studied in a randomized double-blind trial conducted in 6357 men and women aged 40-64 years with uncomplicated essential hypertension (diastolic blood pressures 100-125 mmHg). At the start of the trial 3185 patients received treatment based on a beta-blocker (oxprenolol), while in the remaining 3172 placebo replaced oxprenolol. Supplementary drugs, excluding beta-blockers, were used as necessary in both treatment groups, with the aim of reducing diastolic pressure to 95 mmHg or less. Patients were followed for 3-5 years, a total of 25 651 patient years at risk. In most respects the two groups fared equally well; sudden death (relative risk [RR] 1.08; 95% confidence interval [Cl] 0.68 and 1.72), myocardial infarction (RR 0.83; Cl 0.59 and 1.16) and cerebrovascular accident (RR 0.97; Cl 0.64 and 1.47) rates were similar. Beta-blocker based therapy was associated with significantly lower average blood pressures, earlier ECG normalization, less hypokalaemia and fewer withdrawals from double-blind treatment for uncontrolled hypertension. Doctor-elicited and patient-assessed unwanted effects demonstrated overall good tolerability. In smokers the cardiac event rate was doubled. We propose that beta-blocker treatment effects depend on smoking status, with a significant interaction benefiting non-smoking men. Lower blood pressures during treatment were associated with substantially lower rates for cardiac as well as cerebrovascular events. Proportional hazards analysis also underlines the importance of other cardiovascular risk factors. The IPPPSH stresses the need for a comprehensive approach to the management of blood pressure and other risk factors in hypertensive patients.

The relative antihypertensive potency of propranolol, oxprenolol, atenolol, and metoprolol given once daily. A double-blind, crossover, placebo-controlled study in ambulatory patients

The antihypertensive effect of four beta-blocking agents given once daily was compared with that of placebo in a prospective, crossover, double-blind study of 150 patients. The preparations tested were slow-release propranolol hydrochloride, 160 mg, atenolol, 100 mg, slow-release oxprenolol hydrochloride, 160 mg, and metoprolol, 200 mg. Propranolol and atenolol produced a significant decline in lying, standing, and postexercise blood pressure and pulse rate values. The effects of oxprenolol and metoprolol were not significantly different from that of placebo.