[Diuretics in the treatment of congestive heart failure].
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Biomedical subjects
Publications and source records attributed to L Corea.
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The short- and long-term effects of two calcium channel blocking drugs, verapamil and nifedipine, on blood pressure, heart rate, plasma catecholamines, plasma renin activity, plasma volume and cardiac performance (echocardiography) were studied in essential hypertensive patients and in normal subjects. Verapamil, 160 mg orally, reduced blood pressure within 60 minutes in 22 hypertensive patients, but not in 12 normotensive subjects. Nifedipine, 10 mg sublingually, reduced blood pressure within 15 minutes in 19 hypertensive patients, but not in 7 normotensive subjects. Plasma noradrenaline was significantly increased both in normal subjects and in hypertensive patients only after nifedipine was administered. Verapamil (80 mg three times a day) first, and nifedipine (10 mg three times a day) thereafter, or vice versa, were given to 12 hospitalized hypertensive patients on a fixed sodium and potassium intake; the drugs produced similar blood pressure reductions, but heart rate and plasma catecholamines were increased only after nifedipine (p less than 0.05). Neither drug affected plasma volume, aldosterone or plasma renin activity. Long-term ambulatory treatment with verapamil (80 or 160 mg three times a day for 2 to 4 months) or nifedipine (10 mg three times a day for 2 months) produced changes in all variables that were similar to those observed in the hospital (controlled) study. Shortening fraction was significantly increased after nifedipine (p less than 0.05) but no change was observed after verapamil. In conclusion, blood pressure is effectively reduced by both verapamil and nifedipine; an appreciable adrenergic stimulation may be caused by nifedipine, but usually not by verapamil, and fluid retention, renin release or myocardial depression is not observed during verapamil or nifedipine treatment.
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Twenty-seven mild to moderate essential hypertensive patients were treated with captopril alone or combined with hydrochlorothiazide and left ventricular echocardiographic changes were evaluated after 1, 3 and 6 months. The left ventricular mass decreased slightly after 3 months, together with mean wall stress and total peripheral resistance, while the cardiac performance, as measured by fractional shortening and cardiac output, was unaffected. A high degree of individual variability was observed, and only 9 out of 20 patients examined after 3 months had a consistent reduction in left ventricular mass. The effect of captopril on the isomyosin composition was also evaluated in 4 normotensive rats after 12 weeks of drug administration. No interference with the physiological pattern was observed and no modifications of the biochemical and structural properties of the myocardium were detected.
In a multicenter, randomized, double-blind study, 108 hypertensive patients were treated with either chlorthalidone 25 mg or slow-release metoprolol 200 mg both given once daily over 4 weeks. Blood pressure and heart rate at rest and at the peak of an isometric exercise test (30% of maximal voluntary contraction for 3 min) were recorded at random and at the end of the study. Both treatments induced a significant (p less than 0.01) blood pressure reduction at rest and at the peak exercise, 50.0% of patients on chlorthalidone and 59.2% on metoprolol, respectively, having a lying diastolic blood pressure less than 95 mmHg. A weak but significant (p less than 0.001) positive correlation was found between age and change in systolic and diastolic blood pressure after chlorthalidone. Such a relationship was absent in the metoprolol group, where a significant (p less than 0.01) positive correlation was found between diastolic pressure rise from rest to the peak exercise at randomization, and the reduction in resting diastolic pressure at the end of the study. Treatments were well tolerated, only a decrease (p less than 0.05) in serum potassium (from 4.4 to 4.0 mEq/l) in the chlorthalidone group was observed. Results suggest that age may influence the antihypertensive response to chlorthalidone, while diastolic pressure rise in isometric exercise may predict the degree of pressure response to sustained beta-adrenergic blockade with metoprolol.
1. Nifedipine, a calcium antagonist drug, was given sublingually (10 mg) to seven normal subjects and 19 patients with essential hypertension. In addition, 12 of the hypertensive subjects then received nifedipine (10 mg thrice daily) for 3 weeks. 2. Sublingual administration of nifedipine in hypertensive patients induced a prompt and sustained reduction of blood pressure, without a significant increase of heart rate; in normotensive subjects blood pressure did not change, and heart rate was significantly increased. After chronic treatment, blood pressure remained reduced and heart rate did not rise. 3. Plasma catecholamines and plasma renin activity increased significantly in normotensive subjects after acute administration. 4. After both acute and chronic administration, only plasma noradrenaline was significantly increased in hypertensive patients; in long-term treatment, it was increased in both the lying and standing positions. 5. Nifedipine is an active antihypertensive drug, which may induce some degree of sympathetic activation.
Tienilic acid (TA) is a common new diuretic agent with a potent uricosuric action. In a double-blind cross-over study its antihypertensive effect was compared to that of hydrochlorothiazide (HCT). 20 patients with essential hypertension were studied: after I weeks of placebo wash-out 10 patients received TA (dose range 250-750 mg/die) and 10 HCT (dose range 50-150 mg/die), for 5 weeks. Systolic and diastolic blood pressures were significantly and equally reduced (p < 0.001) after the first week of treatment in both groups. While serum uric acid concentration increased after HCT, it was significantly reduced (p < 0.001) after TA treatment. Serum potassium was slightly reduced with both treatments. Serum tryglicerides, unchanged after HCT, showed a slight tendency to reduction on TA treatment. Ten patients with congestive heart failure, on full digitalis treatment, were given TA (dose range 250-1000 mg/die): in each patient a prompt diuretic effect was observed, associated to a significant reduction of body weight and to a marked improvement of the clinical signs of heart failure. Therefore, TA is an effective diuretic agent which may be conveniently used in the treatment of arterial hypertension and congestive heart failure, as it induces a diuretic effect comparable to that obtained with HCT, reducing at the same time, serum uric acid levels.
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Arterial plasma noradrenaline and adrenaline concentrations before, during and after an attack of pain, induced first by constant supine exercise and then by multistep atrial pacing, were determined in four patients with coronary occlusion disease and stable angina pectoris. An identical protocol was applied to a patient with atypical precordial pain (anxiety state) and normal coronary arteriograms. When compared, the results led to the following conclusions: 1) during supine exercise arterial plasma catecholamine concentrations, particularly noradrenaline, progressively increase, reaching highest values in temporal coincidence with the onset or the peak of pain, 2) during multistep atrial pacing-induced angina no significant changes of arterial plasma catecholamine concentrations are seen. These data, obtained from the same patients, further emphasize that the application of atrial pacing to the study of pathophysiology of angina pectoris and for evaluating antianginal drugs, especially if interfering with adrenosympathetic system activity, must be considered with caution.
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