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

We compared methods of classifying hypertension according to plasma renin activity in 54 patients with essential hypertension and examined the validity of using these classifications to choose between two hypotensive drugs. A prospective, double-blind crossover study was used. Normal values for plasma renin activity were established from 111 control subjects. Plasma renin activity was related to race and inversely to age in hypertensive patients (P less than 0.05) but not in normal subjects. Three methods of classification correlated well but did not identify exactly the same renin-suppressed patients. Chlorthalidone produced a greater reduction in blood pressure and restored blood pressure to normal in a larger percentage of patients in both low-renin (59 per cent) and normal-renin (32 per cent) subgroups than propranolol (12 and 16 per cent). Renin determinations are of limited benefit in the choice of therapy for most patients with essential hypertension.
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PMID:Renin profiling in hypertension and its use in treatment with propranolol and chlorthalidone. 77 25

The mechanisms of anti-hypertensive effect of diuretics remain unknown. The purpose of this study was to test the hypothesis that long-term treatment with chlorthalidone decreases the responsiveness of resistance vessels to neurohormones. The study was performed in deoxycorticosterone acetate (DOCA)-salt hypertensive rats with and without treatment with chlorthalidone (Chlor. 8 mg/day, for 20 days). Resting mean arterial pressure in freely moving state was significantly reduced in DOCA-salt-Chlor rats when compared to DOCA-salt rats (116 +/- 3 vs 147 +/- 7 mmHg, respectively). Chlorthalidone treatment reduced the high plasma sodium content observed in DOCA-salt rats to the same levels observed in normotensive control groups. Results obtained in isolated perfused mesenteric arteries showed: a) the increase in perfusion pressure elicited by norepinephrine (NE), serotonin (SE) and vasopressin (VP) was significantly greater in DOCA-salt than in DOCA-salt + Chlor rats or control normotensive rats; b) the endothelium removal increased the pressor responses to NE, SE and VP in a similar way in all groups. These data provide evidence that long-term chlorthalidone treatment reduces vascular hyperresponsiveness to these neurohormones. In addition, these results indicate that this reduction in vascular hyperresponsiveness, associated with a decrease in extracellular sodium level, could be a possible mechanism by which the diuretics reduce the high blood pressure.
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PMID:Chlorthalidone reduces vascular hyperresponsiveness in DOCA-salt hypertensive rats. 162 12

In the present work the clinical, biological, radiological, electrocardiographic and hormonal characteristics are analyzed in 51 patients suffering mild essential hypertension, in whom treatment with captopril in monotherapy or associated to chlortalidone managed to normalize arterial pressure and maintained the pressure control during a period of one year. Captopril in monotherapy at a dose of 50 to 150 mg/day normalized blood pressure in 34 patients (66.7%) while in the remaining 17 patients (33.3%) the association of 25 mg of Chlortalidone was required. When comparing the subgroup of patients whose blood pressure levels were controlled with captopril as the only used drug (Group A) against those who required the association with diuretics (Group B), we could only observe significant differences regarding the blood pressure level and cardiothoracic index, being these higher in the group of patients who required pharmacologic association. We conclude that only the severity of hypertension allows to predict the necessity of associating a diuretic to captopril in order to obtain the control of blood pressure levels.
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PMID:[Do clinical parameters exist that permit predicting the need to combine a diuretic with captopril in the initial treatment of essential arterial hypertension?]. 209 Nov 31

Hypertension caused by deoxycorticosterone-salt (DOC-salt) may involve enhanced sympathetic tone and some diuretics may exert their antihypertensive action by modulating presynaptic adrenergic sensitivity. This study analyzes the noradrenergic sensitivity of the perfused mesentery isolated from DOC-salt hypertensive rats treated or not with chlorthalidone. Chlorthalidone treatment reduced arterial hypertension in DOC-salt treated rats (from 160 +/- 7 to 127 +/- 5 mmHg). The diuretic completely prevented the increase in sympathetic tone and blunted the decreased vagal tone observed in DOC-salt rats. Norepinephrine-induced vasoconstriction was enhanced in perfused mesenteries isolated from DOC-salt rats. This alteration was attenuated in preparations from chlorthalidone-treated DOC-salt animals. Blockade of neuronal catecholamine uptake using cocaine did not change these responses. These data suggest that chlorthalidone reduces the vascular hyperresponsiveness to catecholamines observed in DOC-salt treated hypertensive rats.
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PMID:Chlorthalidone alters the vascular reactivity of DOC-salt hypertensive rats to norepinephrine. 210 Oct 67

ISH is a distinct pathogenetic entity defined by SBP readings of greater than or equal to 160 and DBP less than 90 mmHg. The etiology, although not well understood, is in some manner related to a reduction in connective tissue elasticity of large blood vessels and an increase in aortic impedance or a decrease in aortic wall compliance. The pathophysiologic consequences include an increased resistance to systolic ejection of blood and a disproportionate increase in SBP. Although not directly related, there is an important increase in peripheral vascular resistance. The prevalence of ISH in several studies is about 7 percent in those over age 60 and increases with age to nearly 20 percent in those over age 80. There is higher prevalence in females and nonwhites. The guidelines for detection of ISH are similar to those for blood pressure evaluation in general. Precautions for detection and evaluation in the elderly include multiple blood pressure measurements in the fasting state and sitting and supine blood pressure measurements before and during therapy. Pseudohypertension, although rare, should be kept in mind. There is a clear risk associated with ISH for stroke, CVD, and premature death, which increases with age and rising levels of SBP. ISH can be controlled effectively with pharmacologic therapies. A reasonable goal is a 20 mmHg reduction in systolic pressure. Proof of reduced risk for stroke, CHD, and death in those with controlled ISH remains to be demonstrated. The SHEP pilot study has demonstrated feasibility of addressing this issue. The full-scale SHEP study addresses this issue and has completed recruitment of the desired sample size and is in follow-up phase. Scheduled completion is in 1991. While we wait for the SHEP full-scale trial results, the prudent approach is for nonpharmacologic therapy and use of pharmacologic agents in that group of patients who demonstrate a large cardiovascular risk burden or increasing symptoms specifically associated with hypertension. The decision to treat must be on an individual patient basis. Pharmacologic therapy is possible in most patients with few or no adverse effects. The "low and slow" approach to therapy is helpful in minimizing these adverse effects. Low-dose diuretics have been documented to be effective in blood pressure control. Chlorthalidone, 12.5 or 25 mg per day, is suggested. Other agents, such as beta-blockers, reserpine, ACE inhibitors, and calcium channel blockers, are best used as Step 2 agents.
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PMID:Systolic hypertension in the elderly: controlled or uncontrolled. 218 67

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.
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PMID:Efficacy and tolerability of long term oxprenolol and chlorthalidone singly and in combination in hypertensive blacks. 219 98

The unpredictable effect of antihypertensive therapy on coronary risk resulting from changes in lipid levels is an increasingly recognized problem. Different drugs have been shown to exert varying effects on lipids. This problem is particularly evident in young hypertensive patients who may be candidates for lifelong therapy. The effects of chlorthalidone and metoprolol on fasting plasma lipids and lipoprotein levels were compared in two similar nonrandomized groups of patients with mild hypertension. Chlorthalidone therapy was associated with an increase in serum cholesterol of 8.1% (17 mg/dl), mainly reflecting an increase in low-density lipoprotein (LDL) cholesterol. Serum triglycerides increased by 16% (20 mg/dl) and high-density lipoprotein (HDL) cholesterol levels decreased by 10% (3 mg/dl, not significant). Metoprolol therapy induced no changes in total, low, very low, or high-density lipoprotein. Serum triglyceride concentration increased by 22% (28 mg/dl). Application of the Israel Ischemic Heart Disease Study data to these findings indicates a slight decrease at most in the 5-year estimated probability of myocardial infarction in the chlorthalidone-treated group, whereas a clearly favorable influence on the calculated risk of coronary heart disease was observed for those treated with metoprolol. These data suggest that the different forms of therapy for mild hypertension carry varying degrees of significance in terms of risk of coronary heart disease, which should be considered when choosing medication.
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PMID:Do beta-blockers alter lipids and what are the consequences? 248 Nov 77

We compared the effects of relaxation therapy in hypertensive patients taking placebo, a beta-blocker (atenolol, 100 mg/d), or a diuretic (chlorthalidone, 50 mg/d), and we also compared the effects of relaxation therapy with the effects of the latter two drugs alone. Blood pressures were measured not only in the relaxation therapists' office and at a hypertension clinic, but also in the patient's environment by means of 24-hour ambulatory blood pressure recordings. The effect of relaxation therapy, while statistically significant, was modest. There was no generalization of effect to ambulatory blood pressure. Atenolol was significantly more effective than relaxation in reducing both systolic and diastolic pressure. Chlorthalidone was significantly more effective than relaxation in reducing systolic but not diastolic pressure in the hypertension clinic only. The long-term effects of relaxation were independent of concomitant drug use, but within the actual relaxation sessions blood pressure dropped further during chlorthalidone than during placebo or atenolol treatment.
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PMID:Relaxation therapy for hypertension. Comparison of effects with concomitant placebo, diuretic, and beta-blocker. 287 44

The clinical efficacy and tolerability of fenquizone (10 mg), a thiazide-like diuretic, were studied in comparison with chlorthalidone (25 mg) in 20 hypertensive out-patients during a four-month treatment course. Both drugs were very active in reducing hypertension. Fenquizone proved to be more active on systolic blood pressure, while there were no differences between groups regarding diastolic blood pressure. Chlorthalidone induced a more significant loss of plasma K+ than fenquizone. Fenquizone showed also a significant decrease of symptoms (headache, dizziness) due to hypertension. No undesirable side effects were observed.
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PMID:Double-blind crossover study of fenquizone compared to chlorthalidone in essential hypertension. 390 76

Nineteen patients with uncomplicated essential hypertension and low activity of plasma renin in response to a change from recumbency to an upright posture along with furosemide administration were given spironolactone, 400 mg/d, or chlorthalidone, 100mg/d, in a double-blind, random-sequence, crossover trial. The sequence of treatments was placebo for 2 months, one active drug for 2 months, placebo again for 1 month and the other active drug for 2 months. With both active treatments the average systolic, diastolic and mean arterial pressures decreased significantly. The two agents were equally efficacious in lowering the blood pressure regardless of the severity of hypertension during placebo treatment. Body weight, 24--hour urinary excretion of sodium, the plasma renin activity and the plasma aldosterone level at the end of the initial placebo period did not allow us to predict the response to either drug. Both drugs reduced the body weight and increased the stimulated plasma renin level activity. Chlorthalidone significantly increased the serum uric acid level and significantly reduced the serum potassium level. Three patients experienced orthostatic dizziness during spironolactone therapy, but no adverse symptoms were observed with chlorthalidone therapy. Thus, spironolactone is an effective alternative to thiazide-type drugs in patients with low-renin essential hypertension.
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PMID:Comparison of chlorthalidone and spironolactone in low--renin essential hypertension. 633


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