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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To compare the antihypertensive effect of two beta-blocking agents, metoprolol (Seloken) and atenolol (Tenormin), a double-blind study was performed in 55 patients. Following a six-week placebo period the patients, who all had mild to moderate essential hypertension (WHO I-II), were randomly allocated to treatment with either metoprolol (n = 28) or atenolol (n = 27). During a six-week period they received 100 mg of either drug once daily. For patients who at the end of that period did not reach a diastolic blood pressure (BP) of less than 95 mmHg the daily dose was increased to 200 mg. Patients who responded (diastolic BP less than 95 mmHg) continued on the initial dosage regimen. When comparing the two groups with regard to the reduction of BP, there was no difference either 24 hours after the last dose or 5-9 hours after drug administration. The decrease in supine systolic/diastolic BP was 18/16 mmHg on metoprolol and 20/16 on atenolol. The decrease in heart rate was comparable in the two groups. Eight patients in the metoprolol and 7 in the atenolol group had their dose increased to 200 mg at the end of the first six-week period. This means that the number of patients not responding to 100 mg daily was comparable in the two groups. We did not observe any differences in side-effects of the two drugs. The results clearly suggest that atenolol and metoprolol are equipotent following once daily administration in patients with mild to moderate hypertension.
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PMID:Metoprolol and atenolol administered once daily in primary hypertension. A clinical comparison of the efficacy of two selective beta-adrenoceptor blocking agents. 701 97

A double-blind within-patient study was carried out on Zimbabwean Blacks to investigate the effect of once-daily atenolol on hypertension in doses of 100 and 200 mg/d. Atenolol 200 mg produced significant changes in diastolic pressure readings taken in the supine and standing positions and after exercise; with atenolol 100 mg modest but non-significant changes occurred. These findings are less impressive than those previously reported in White subjects. We conclude that beta-adrenoceptor blocking agents should not be used as drugs of first choice for hypertension in our Black population.
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PMID:Once-daily atenolol in hypertensive Zimbabwean blacks. A double-blind trial using two different doses. 701 66

Atenolol 100 mg and penbutolol 40 mg given once a day were both effective in controlling moderate hypertension, as judged by a randomised controlled, double-blind trial in 45 patients treated for six weeks. Both drugs significantly reduced the resting supine and erect blood pressures. No serious adverse effects could be attributed to either drug. Bradycardia occurred more frequently with atenolol than with penbutolol. Penbutolol, which possesses intrinsic sympathomimetic activity, may be useful in the treatment of patients in whom some other beta-blocker has failed to bring about adequate control of the blood pressure, despite marked bradycardia.
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PMID:Use of fixed doses of beta blocking drugs in the treatment of hypertension. Randomised study of atenolol and penbutolol. 704 70

1 The report presents the effects on blood lipids and uric acid of six different antihypertensive drugs, used alone and of five different combinations of two antihypertensive drugs. 2 Prazosin significantly lowered serum LDL + VLDL cholesterol and total triglycerides. Atenolol lowered LDL + VLDL cholesterol to a smaller but significant extent. Both pindolol and hydrochlorothiazide (HCTH) were without effect, while oxprenolol significantly increased total triglycerides. Propranolol significantly lowered HDL cholesterol and increased total triglycerides and uric acid. 3 The combination prazosin and pindolol had a favourable effect on the lipid profile, while the combination propranolol and HCTH lowered HDL cholesterol but increased total triglycerides. Propranolol and prazosin lowered HDL cholesterol, while methyldopa and HCTH, and HCTH and amiloride were without effect on blood lipids. 4 It is suggested that the metabolic effects of antihypertensive drugs could be of special importance in long-term treatment of mild hypertension.
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PMID:Antihypertensive drugs and blood lipids: the Oslo study. 710 58

Atenolol, a cardioselective beta-adrenergic blocking agent, was given as the sole hypotensive drug for 8-12 weeks to 20 patients with hypertension of varying degrees of severity. Initial systolic blood pressure ranged from 162-238 mm Hg (mean +/- SEM 196 +/- 5.5 mm Hg) and diastolic blood pressure ranged from 105-143 mm Hg (118 +/- 2.5 mm Hg). Three patients had accelerated hypertension, six had cardiomegaly with recent exertional dyspnea and three were diabetics. Atenolol, 100-300 mg once daily, controlled both the supine and standing blood pressure and markedly attenuated the initial hypertensive response to severe exercise. In 17 patients (85%), atenolol therapy reduced blood pressure more than 20/10 mm Hg; however, adequate blood pressure control was not achieved in severe hypertension. A significant hypotensive action developed within 2 weeks of treatment, and control of hypertension was maintained for 2 weeks after sudden interruption of therapy. No patient had postural or postexercise hypotension. The drug appeared to exert its maximum hypotensive effect at the 100-mg dosage. The magnitude of the hypotensive response was related to the initial systolic blood pressure (r = 0.77, p less than 0.01) and the degree of inhibition of exercise tachycardia (r = 0.66, p less than 0.01). The atenolol plasma level and its hypotensive action were not related. Except for impairment of glucose tolerance in diabetic patients, atenolol had minimal side effects.
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PMID:Clinical evaluation of atenolol in hypertensive patients. 724 4

1 The pharmacological properties of atenolol suggest its possible usefulness in pregnancy-induced hypertension. The pharmacokinetics of atenolol in the pregnant woman, concentrations in cord blood, and its effects on maternal blood pressure and the foetus, are evaluated. 2 We studied 13 pregnant women with hypertension, most of them uncontrolled on methyldopa. Whole blood concentrations and urinary excretion of the drug were measured over 24 h following a 100 mg dose. Effects on maternal blood pressure, pulse rate and foetal heart rate and cardiotocograph were compared for the 4 days before treatment and the first 4 days of treatment. The birth weights and Apgar scores of the babies were recorded. 2 The pharmacokinetics of atenolol (plasma half-life of about 8 h) in pregnant women do not differ from the findings in the non-pregnant. The levels of atenolol in the cord blood were confirmed as approximately equal to those in the maternal blood. 4 In the ten women in whom blood pressure was assessed a small significant fall in blood pressure was observed. 5 A 5% mean fall in foetal heart rate resulted but in one case was a rate below 120 beats/min recorded. There was no evidence of depression of the stress response of the foetal heart. Apgar scores 5 min post partum were satisfactory. 6 Atenolol appears to be safe for use in hypertensive pregnancies. Its effectiveness as an antihypertensive agent in pregnancy requires further controlled evaluation.
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PMID:Atenolol in the treatment of pregnancy-induced hypertension. 733 38

1 In an open, randomized cross-over investigation of thirteen patients (nine and four women, aged 37-67 years) with mild or moderate essential hypertension a comparison between atenolol and metoprolol was carried out in order to study the effects of 50, 100 and 200 mg given once daily on blood pressure and heart rate at rest and during exercise. 2 Before one beta-adrenoceptor blocking drug was replaced by the other in a patient an intervening drug-free interval of sufficient length was secured to allow an increase in the blood pressure to pretreatment levels. 3 A maximal fall in blood pressure was achieve with 50 mg atenolol once daily, with no further reduction when the dose was increased to 100 mg or 200 mg. Maximal blood pressure reduction was achieved with 100 mg metoprolol daily, while the hypertensive effect of 50 mg once daily was not consistent. Significant reductions in heart rate in all test situations were observed with 50 mg atenolol, while 200 mg metoprolol 100 was necessary to reduce exercise-induced tachycardia. 4 Atenolol 50 mg and metoprolol 100 mg once daily are efficient in treating mild or moderate hypertension and doses beyond these may not reduce the blood pressure further. On the contrary lower doses than generally recommended may be effective in the individual patient.
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PMID:A comparative study of atenolol and metoprolol in the treatment of hypertension. 734 Aug 90

beta-Adrenoceptor antagonists such as propranolol and atenolol ameliorate the symptoms of human hyperthyroidism. We wished to define whether the cardiac changes of hyperthyroidism are attenuated by treatment with the beta-adrenoceptor antagonist atenolol. Rats were treated with triiodothyronine (T3) [1 mg/kg/day subcutaneously (s.c.) for 14 days] together with oral atenolol (100 mg/day on days 8-14); physiological parameters, inotropic and chronotropic responses in isolated cardiac tissues to compounds that increase intracellular cyclic AMP, and ventricular beta 1- and beta 2-adrenoceptors were measured. Administration of T3 produced marked hyperthyroidism, leading to increased metabolism, cardiac hypertrophy, tachycardia, hypertension, marked decrease in or loss of positive inotropic responses to calcium chloride, norepinephrine (NE), forskolin, and theophylline and increased ventricular beta 1- and beta 2-adrenoceptor density. Atenolol treatment of hyperthyroid rats attenuated the increases in heart rate (HR), rectal temperature, and O2 consumption but did not alter cardiac hypertrophy, hypertension, decreased positive inotropic responses or increased beta-adrenoceptor density. We conclude that beta-adrenoceptor antagonists produce only limited changes in hyperthyroidism-induced cardiovascular responses; furthermore, beta-adrenoceptor antagonists are unlikely to attenuate the cardiovascular risk factors of hyperthyroidism.
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PMID:Beta-adrenoceptor antagonism and the hyperthyroid rat heart. 752 70

Hypertensive crises are now uncommon in developed countries, and few doctors will have experience in their management. A review of the drugs used by clinicians in Scotland suggests considerable diversity in approach but broadly follows the best advice that is available in the literature. For emergencies such as hypertensive encephalopathy and hypertension associated with aortic dissection in which irreversible damage would occur within hours if left untreated, patients should probably be admitted to Intensive Care Units and be given nitroprusside. Similarly nitroprusside or nitroglycerin would be appropriate choice for hypertension that is complicated by acute left ventricular failure. By contrast if the risk to the patient is measured in days rather than hours then oral therapy will be quite sufficient. Atenolol or nifedipine retard can safely be given as initial treatment for uncomplicated malignant hypertension, and nifedipine retard can be used for the milder cases of encephalopathy or heart failure. The use of sublingual drugs in the management of hypertensive emergencies and urgencies cannot be recommended as the fall in blood pressure is both unpredictable and uncontrolled with the consequent and unacceptable risk of organ ischaemia.
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PMID:Management of hypertensive crises. 760 39

Centrally acting antihypertensive drugs are recognized to be safe and effective treatment for high blood pressure. Centrally mediated side effects, such as sedation, are commonly dose- and treatment-limiting events. Imidazoline-preferring receptors, while functionally similar to alpha 2 adrenoceptors, are distinguishable not only on the basis of in vitro radioligand binding but also in vivo in terms of side effects. Drugs with an imidazoline structure lower blood pressure but are less likely to impair psychomotor function. A placebo-controlled study compared moxonidine 0.1 mg with clonidine 0.1 mg orally in nine normal subjects. Both active drugs lowered blood pressure compared to placebo (clonidine more than moxonidine). However, psychomotor function and self-scored sedation and dry mouth were significantly affected only by clonidine. In a long-term (4 weeks) double-blind cross-over study in essential hypertension, rilmenidine was well tolerated and had similar effects to those of atenolol on erect and supine blood pressure. Rilmenidine had no effect on a wide range of autonomic and psychomotor tests or on responses to mental or physical stress. Atenolol, by contrast, had the predicted effects of a beta adrenoceptor antagonist on heart rate during exercise and the Valsalva maneuver. Imidazoline-preferring drugs offer a new and realistic approach to antihypertensive therapy with blood pressure reduction not limited by marked sedation within the therapeutic dose range.
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PMID:Clinical pharmacology of drugs acting on imidazoline and adrenergic receptors. Studies with clonidine, moxonidine, rilmenidine, and atenolol. 767 87


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