Thiazide diuretics hypertension

Turner, S.T., et al., "C825T Polymorphism of the G Protein Beta(3)-Subunit and Antihypertensive Response to a Thiazide Diuretic," Hypertension, 37, 739-743 (2001). 

Bendroflumethiazide - thiazide diuretic hypertension, cardiac failure... 

Thiazide diuretic Hypertension This effect may be an unusual adverse... 

In contrast to the dose limitations when thiazide diuretics used as monotherapy, the treatment of severe hypertension that is unresponsive to three or more drugs may require larger doses of the thiazide diuretics. Hypertensive patients may become refractory to drugs that block the sympathetic nervous system or to vasodilator drugs because these drugs engender a state in which the blood pressure is very volume-dependent. It therefore is appropriate to consider the use of thiazide diuretics... 

Thiazide diuretics have a venerable history as antihypertensive agents until the advent of the angiotensin-converting enzyme (ACE) inhibitors this class of drugs completely dominated first line therapy for hypertension. The size of thi.s market led until surprisingly recently to the syntheses of new sulfonamides related to the thiazides. Preparation of one of the last of these compounds starts by exhaustive reduction of the Diels-Alder adduct from cyclopentadiene and malei-mide (207). Nitrosation of the product (208), followed by reduction of the nitroso group of 209,... 

G protein p-3 subunit Truncated protein with increased signal transduction in carriers of the 825T allele. Associated with hypertension and with the response to thiazide diuretics. 

Amiloride (Midamor) is used in the treatment of CHF and hypertension and is often used with a thiazide diuretic. Spironolactone and triamterene are also used in tiie treatment of hypertension and edema caused by CHF, cirrhosis, and the nephrotic syndrome Amiloride, spironolactone, and triamterene are also available with hydrochlorothiazide, a thiazide diuretic that enhances tiie antihypertensive and diuretic effects of the drug combination while still conserving potassium. 

In patients with chronic kidney disease and hypertension, ACE inhibitors and ARBs are preferred, usually in combination with a diuretic.67 ACE inhibitors in combination with a thiazide diuretic are also preferred in patients with a history of... 

Two types of diuretics are used for volume management in HF thiazides and loop diuretics. Thiazide diuretics such as hydrochlorothiazide, chlorthalidone, and metolazone block sodium and chloride reabsorption in the distal convoluted tubule. Thiazides are weaker than loop diuretics in terms of effecting an increase in urine output and therefore are not utilized frequently as monotherapy in HF. They are optimally suited for patients with hypertension who have mild congestion. Additionally, the action of thiazides is limited in patients with renal insufficiency (creatinine clearance less than 30 mL/minute) due to reduced secretion into their site of action. An exception is metolazone, which retains its potent action in patients with renal dysfunction. Metolazone is often used in combination with loop diuretics when patients exhibit diuretic resistance, defined as edema unresponsive to loop diuretics alone. 

Thiazide diuretics such as chlorothiazide act on the distal tubule, a portion of the tubule that is permeable to sodium. The mechanism of action of these diuretics involves inhibition of NaCl reabsorption by blocking the Na+, CL symporter in the luminal membrane. The thiazide diuretics are only moderately effective due to the location of their site of action. Approximately 90% of the filtered Na+ ions have already been reabsorbed when the filtrate reaches the distal tubule. These drugs may be used for treatment of edema associated with heart, liver, and renal disease. Thiazide diuretics are also widely used for the treatment of hypertension. 

The answer is a. (Katzung, pp 255-256.) Thiazide diuretics can be used in the treatment of nephrogenic diabetes insipidus. Its other uses include the treatment of hypertension, CHF, and nephrolithiasis due to idiopathic hypercalcuria. 

Most patients with stage 1 hypertension should be treated initially with a thiazide diuretic, angiotensin-converting enzyme (ACE) inhibitor, angio-... 

Thiazide diuretics act on the beginning of the distal convoluted tubule by inhibiting sodium re-absorption. Thiazide diuretics are indicated in hypertension, and at higher doses to relieve oedema caused by heart failure. Thiazide diuretics lead to hyponatraemia and hypokalaemia. They may cause hypercalcaemia and are therefore avoided in patients with this condition. 

Thiazide diuretics (benzothiadia-zines) include hydrochlorothiazide, benzthiazide, trichlormethiazide, and cyclothiazide. A long-acting analogue is chlorthalidone. These drugs affect the intermediate segment of the distal tubules, where they inhibit a Na+/Ch cotransport, Thus, reabsorption of NaQ and water is inhibited. Renal excretion of Ca decreases, that of Mg + increases. Indications are hypertension, cardiac failure, and mobilization of edema. 

In addition to the thiazide diuretics like hydrochlorothiazide (19) and chlorthalidone used in the treatment of hypertension for a long time, a few newer diuretics such as azosemide and torasemid (188) have been introduced for... 

It is used for treating hypertension in patients who do not respond to thiazide diuretics. It can be nsed as an adjuvant drug in thiazide treatment for reaching an optimal level of blood pressnre. A synonym of this drag is hylorel. 

The abihty of metolazone, chlorothalidone, and indapamide to remove edematous liquid from the body is practically identical to that of thiazide diuretics. These drugs are used for relieving edema associated with hepatic, renal, and cardiac diseases, as well as for treating general hypertension either independently, or in combination with other drugs. 

Hypertension therapy suggests wide use of diuretics, including thiazide diuretics, drugs related to them, such as metolazone (21.3.20) and indapamide (21.3.26), furosemide (21.4.11), loop diuretics, as well as potassium sparing diuretics—spironolactone (21.5.8), triamterene (21.5.13), and amyloride (21.5.18). 

The molecular mechanism of diuretics acting as antihypertensive agents is not completely clear however, use of diuretics causes a significant increase in the amount of water and electrolytes excreted in urine, which leads to a reduction in the volume of extracellular fluid and plasma. This in turn leads to a reduction of cardiac output, which is the main parameter responsible for a drop in arterial blood pressure and venous blood return. Cardiac output is gradually restored, but the hypotensive effect remains, possibly because of the reduced peripheral resistance of vessels. It is also possible that diuretics somehow lower vascular activity of noradrenaline and other factors of pressure in the organism. Methods of synthesizing thiazide diuretics used for hypertension are described in the preceding chapter. Chapter 21. 

Essential hypertension - For the treatment of patients with essential hypertension. It may be used alone or given with other classes of antihypertensives, especially thiazide diuretics. 

Reduction of peripheral vascular resistance and cardiac afterload, probably because the enhanced loss of the sodium ions leads to a blunted vasoconstrictor response to endogenous catecholamines. This effect is relevant in the long-term treatment of essential hypertension with thiazide diuretics. 

Salvetti A, Ghiadoni L. Thiazide diuretics in the treatment of hypertension an update. J Am Soc Nephrol 2006 17(4 Suppl 2) S25-9. 

Thiazide diuretics are effective antihypertensive agents in black hypertensive patients and studies suggest that they cause a greater decrease in blood pressure in black patients than in whites. The better hypotensive response in black hypertensive patients is probably due to the fact that, in comparison with whites, more black patients have an expanded intracellular volume and low plasma renin activity. In developing countries, in which the majority of black people live, the cost of therapy is important. Thiazide diuretics are because of their low cost important baseline drugs in the treatment of hypertension. 

Studies with ACE inhibitors have shown that in black patients the response is poor. However, the response becomes the same as in whites when ACE inhibitors are combined with a low-dose thiazide diuretic. ACE inhibitors can be effective in black hypertensive patients but in higher doses compared to white and Indian peoples. 

In summary, black hypertensive patients respond well to thiazide diuretics, CCB, vasodilators like prazosin, doxazosin or the vasodilating /3-blocker la-betalol. It is suggested that in black hypertensive patients a thiazide diuretic should be routinely added when a /3-blocker or an ACE inhibitor is used. This above information is summarized in Table 10. 

Prazosin is effective in reducing all grades of hypertension. The drug can be administered alone in mild and (in some instances) moderate hypertension. When the hypertension is moderate or severe, prazosin generally is given in combination with a thiazide diuretic and a -blocker. The antihypertensive actions of prazosin are considerably potentiated by coadministration of thiazides or other types of antihypertensive drugs. 

Captopril, as well as other ACE inhibitors, is indicated in the treatment of hypertension, congestive heart failure, left ventricular dysfunction after a myocardial infarction, and diabetic nephropathy. In the treatment of essential hypertension, captopril is considered first-choice therapy, either alone or in combination with a thiazide diuretic. Decreases in blood pressure are primarily attributed to decreased total peripheral resistance or afterload. An advantage of combining captopril therapy with a conventional thiazide diuretic is that the thiazide-induced hypokalemia is minimized in the presence of ACE inhibition, since there is a marked decrease in angiotensin Il-induced aldosterone release. 

The p-blockers are quite popular antihypertensive drugs. They are well tolerated, and serious side effects are seldom observed. When used alone over several weeks, p-blockers produce a signihcant reduction in blood pressure in approximately 30% of patients with mild to moderate hypertension. Thus, -blockers can be employed as a first step in the management of high blood pressure. However, they are often used in conjunction with a diuretic when therapy with a single agent is not satisfactory. The combination of a p-blocker, thiazide diuretic, and vasodilator provides signihcant control of moderate to severe hypertension in approximately 80% of patients. 

When a patient is treated with a thiazide diuretic for hypertension, all of the following are likely EXCEPT ... 

C. Although still highly controversial, the initial use of a thiazide diuretic for monotherapy has been recommended by the Joint National Committee on Detection, Evaluation and treatment of High Blood Pressure. Triamterene and Aldactone are rarely used alone and exhibit no antihypertensive activity. A recent study found that the loop diuretics bumetanide and furosemide effectively reduced blood pressure. Serum lipid levels were less affected than with thiazide diuretics or chlorthalidone. However, thiazide diuretics are a more conservative and approved approach for the initial treatment of hypertension that avoid the more dramatic fluid and electrolyte shifts that occur with loop diuretics. 

Do not use fixed combinations of methyldopa and thiazide diuretics for initiai management of hypertension. 

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