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

Any increase in arterial pressure is the result of either an increase in cardiac output, an increase in total peripheral resistance or a combination of the two. Hypertension is not a homogeneous disease, however, and different mechanisms may be operative during the life span of the patient. Hypertension in the young, nonobese patient is usually hemodynamically characterized by high cardiac output, normal to slightly contracted intravascular volume and numerically normal total peripheral resistance. In contrast, hypertension in the middle-aged or elderly patient is usually hemodynamically characterized by normal to low cardiac output, contracted intravascular volume and high total peripheral resistance. Two further subgroups of hypertensive patients can be identified: obese patients, whose hypertension is characterized by high cardiac output, expanded intravascular volume and normal or low total peripheral resistance, and black patients, whose hemodynamic and fluid volume findings are similar to those of their white counterparts, but who tend to have lower heart rates and greater responsiveness to intravascular volume depletion than white hypertensive subjects. A rational therapeutic approach to essential hypertension should take into account these variable pathophysiologic features. Thiazide diuretics continue to be appropriate and generally well-tolerated choices for initial antihypertensive therapy in obese or in black patients. Many obese patients or black patients, however, are likely to develop early left ventricular (LV) hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Use of diuretic agents in obese or black patients with systemic hypertension. 372 40

Recent studies have confirmed the benefits of treating hypertension in the elderly. Thiazide diuretics appear to be effective in achieving goal blood pressure in a majority of patients above the age of 60 years. Increasing concern regarding the biochemical abnormalities associated with diuretic therapy has led to the more widespread use of lower doses of these agents. Preliminary results from a study of hydrochlorothiazide +/- amiloride treatment in 99 hypertensive patients aged 65 to 80 years indicate that hydrochlorothiazide 25 to 50 mg/day will lower diastolic blood pressure to less than 90 mmHg in about 90% of elderly patients with mild to moderate elevations in blood pressure. These lower dosages of hydrochlorothiazide were only occasionally associated with mild hypokalaemia. However, the addition of amiloride to the treatment regimen resulted in the maintenance of normal serum potassium concentrations. Thus, relatively low doses of thiazide diuretics may effectively lower blood pressure in elderly hypertensive patients while causing fewer biochemical abnormalities than previously associated with the use of these drugs.
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PMID:Diuretic therapy for hypertension in the elderly. 373 95

Thiazide therapy is a widely used first line treatment for arterial hypertension. Its useful value, particularly in mild or moderate hypertension, is sometimes reduced by metabolic side-effects, as hypokalaemia and hyperuricaemia. In the present study the antihypertensive efficacy of a new, non-sulphonamide diuretic Bay g 2821 (muzolimine) was evaluated in comparison with the combination of hydrochlorothiazide-amiloride over a period of 4 weeks. A highly significant decrease in systolic and diastolic blood pressures was produced by both treatments. No decrease in serum potassium nor an increase in cholesterol, triglycerides, uric acid or glucose was detected during the 4 week treatment period. Subjective side-effects, such as headache and dizziness, were very rarely observed during Bay g 2821 treatment. The new diuretic appears, therefore, to be effective in the treatment of arterial hypertension without untoward side-effects.
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PMID:Cross-over study of muzolimine and hydrochlorothiazide-amiloride in hypertensive patients. 400 27

Thiazide diuretics are used commonly to treat hypertension. Unfortunately, they also are known to elevate serum cholesterol levels. Because serum lipid fraction levels differ between the sexes, possible sex-related differences in thiazide-induced changes in serum total cholesterol (TC), triglycerides (TG) and high density lipoprotein cholesterol (HDL-C) levels were examined. Four groups of male and female hamsters were treated for a minimum of 3 months with hydrochlorothiazide (HCTZ) at zero, 1, 2 or 4 mg/kg/day. At zero dose, there was no difference in TG levels between the sexes; however, females had significantly higher TG concentrations than did males at 1, 2 and 4 mg HCTZ (all p less than 0.05). Females demonstrate a significant dose response with HCL-C levels increasing with increasing doses of HCTZ, (r = 0.983; p less than 0.02); in contrast males had a similar increase in HDL-C at all dose levels (all p less than 0.05) thus there was no demonstrable dose response (r = 0.539). Total cholesterol concentrations were significantly higher in the females than in males (p less than 0.05) at all 3 dose levels as well as at zero dose. Further, the females demonstrated a direct dose response in TC levels (r = 0.986; p less than 0.02) while the males showed no such dose response (r = 0.824; p less than 0.01). Based on these findings we conclude that: 1) HCTZ increases TG, TC and HDL-C levels in both male and female hamsters; 2) TC levels are higher in females than in males regardless of HCTZ dose; 3) only females show a dose-dependent increase in HCL-C and TC in response to HCTZ. These sex-related changes in lipid fractions occurring with HCTZ treatment, if they occur in humans, may contribute to sex-related differences in rates and severity of atherosclerosis in HCTZ-treated populations.
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PMID:Thiazide-induced hypercholesterolemia: sex differences. 405 54

Pharmacological treatment of hypertension can cause clinically significant alterations in endocrine function through effects on glucose homeostasis, thyroid and parathyroid hormones, adrenal steroid metabolism and reproductive/pituitary physiology. Long term use of thiazide diuretics causes deterioration in glucose tolerance, probably secondary to potassium depletion. Hypoglycaemic complications of beta-blockers (mainly the non-selective compounds) can be dramatic, especially in type I diabetics. Clonidine, diazoxide and calcium antagonists have all been associated with deterioration in glucose tolerance and their long term use should be avoided in type II diabetics if possible. Propranolol lowers T3 levels by decreasing the conversion of T4 to T3. Prazosin causes elevations in T4 and thyroid-stimulating hormone, while sodium nitroprusside use may result in hypothyroidism. Numerous agents are associated with sexual dysfunction, including methyldopa, reserpine, clonidine and spironolactone. Thiazide diuretics may cause hypercalcaemia, particularly in patients with hyperparathyroidism, by decreasing urinary calcium as well as directly influencing bone and gut calcium handling. Conversely, propranolol may decrease circulating parathyroid hormone levels and correct the hypercalcaemia seen in hyperparathyroidism. Awareness of drug-induced changes in endocrine function will facilitate the rational management of the hypertensive patient.
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PMID:Effects of antihypertensive drugs on endocrine function. 614 2

A 24-yr-old woman with hypertension, hypokalemic alkalosis, low plasma renin and hypoaldosteronism was studied. Plasma aldosterone, renin and potassium returned to normal and blood pressure fell after sodium restriction or the administration of triamterene. Thiazide therapy also normalized her blood pressure while dexamethasone, spironolactone and furosemide did not improve her symptoms. Plasma aldosterone levels were low and responded poorly to a short term ACTH injection, but responded well to the maximal adrenal stimulation by ACTH-Z. Plasma levels of cortisol, corticosterone and deoxycorticosterone were within the normal range. Adrenal scintigram with 131I-adosterol and abdominal computed axial tomography did not reveal the presence of a sizeable adrenal tumor. In addition, the urinary kallikrein excretion was low after sodium restriction and showed no response to saline infusion. These findings suggest that the excessive secretion of unusual mineralocorticoids may not exist in this case. From these observations and the results of the therapeutic responses to the diuretic agents, we conclude that the primary cause of the disorder of this patient seems to be a renal defect in the distal tubule in handling sodium and potassium which is similar to that in Liddle's syndrome.
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PMID:Hypertension, hypokalemia and hypoaldosteronism with suppressed renin: a clinical study of a patient with Liddle's syndrome. 627 44

Major trials evaluating antihypertensive therapy are reviewed, and the current issues surrounding the choice of therapy in mild and isolated systolic hypertension are discussed. Several major trials have shown that patients with mild hypertension benefit from therapy. These results have prompted widespread use of antihypertensive agents; however, there are still no clear guidelines on when drug therapy should be initiated. Only the Hypertension Detection and Follow-up Program has shown significant decreases in coronary heart disease (CHD) related deaths. Thiazide diuretics are recommended as agents of first choice in the stepped-care approach to the management of uncomplicated mild to moderate hypertension. The Multiple Risk Factor Intervention Trial evaluated the effects of modifying several cardiovascular risk factors in more than 12,000 high-risk men. It failed to document significant differences in CHD-related mortality in patients who received special care as compared with those who received usual care. Concerns have been raised about the contribution of antihypertensive therapy, particularly diuretics, to the lack of differences in therapeutic outcomes. There is renewed interest in lipid alterations secondary to antihypertensive agents and the effect of diuretic-induced hypokalemia. Antihypertensive therapy should be instituted with an individualized assessment of the potential benefits of therapy relative to the short- and long-term risks of treatment.
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PMID:Current issues in the management of hypertension. 636 15

The introduction of the western diet and lifestyle to Japan has been associated with changes in body build, lipid levels, and disease pattern. An increased incidence of coronary heart disease parallels increased fat intake. Thiazide diuretics and beta blockers may have adverse effects on blood lipids in man leading to an increase in the risk of coronary heart disease; therefore, for many patients these drugs may not offer the optimum treatment strategy. Hence, prazosin, a drug that effectively lowers blood pressure without adversely affecting lipid metabolism, has been evaluated in nine studies within Japan. Prazosin showed adequate antihypertensive effects even at doses as low as 1 to 3 mg per day. Sustained constant blood pressure reductions were achieved with maintenance doses of 3 to 6 mg per day without significant side effects. Even when given in low doses, prazosin increased high-density lipoprotein cholesterol while inhibiting elevations of total cholesterol and decreasing triglycerides. In view of these findings, prazosin as a single agent can be considered for monotherapy of hypertension.
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PMID:Studies on the effect of prazosin on blood pressure and serum lipids in Japanese hypertensive patients. 636 47

Potassium balance was followed in 12 subjects with hypertension during treatment either with timolol and hydrochlorothiazide or with timolol, hydrochlorothiazide, and amiloride. Subjects treated with the beta-blocker and thiazide developed potassium depletion, which was prevented by concomitant treatment with amiloride. Thiazide augments timolol-induced potassium loss and it is suggested that the renal handling of potassium is changed by other mechanisms. The decrement in potassium loss during concomitant amiloride treatment cannot be explained.
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PMID:Thiazide-induced potassium loss not prevented by beta blockade. 637 34

Thiazide diuretics used alone to treat hypertension can cause hypokalaemia in a substantial proportion of patients. The possibility exists that any benefit of reducing high blood pressure by such treatment may be offset by an increased mortality due to arrhythmias initiated by hypokalaemia.
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PMID:Hypokalaemia induced by thiazide diuretics in the treatment of hypertension: a cause for concern, not nihilism. 664


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