Antihypertensive agents hypertensive renal disease

Therapeutic uses Thiazide diuretics decrease blood pressure in both the supine and standing positions postural hypotension is rarely observed, except in elderly, volume-depleted patients. These agents counteract the sodium and water retention observed with other agents used in the treatment of hypertension (for example, hydralazine). Thiazides are therefore useful in combination therapy with a variety of other antihypertensive agents including (3-blockers and ACE inhibitors. Thiazide diuretics are particularly useful in the treatment of black or elderly patients, and in those with chronic renal disease. Thiazide diuretics are not effective in patients with inadequate kidney function (creatinine clearance less than 50 mls/min). Loop diuretics may be required in these patients. 

Diabetes is the most frequent cause of end-stage renal disease. Hypertension, which is common among patients with type 2 diabetes, accelerates the development and progression of renal disease. Early and tight blood pressure control in diabetic patients, preferably with antihypertensive agents that have proven reno-protective properties, is therefore essential to minimize loss of kidney function. Several controlled clinical trials have investigated and proved the beneficial effects of ARBs on type 2 diabetic nephropathy [10-14]. 

Patients with hypertension may develop damage to either the renal tissue (parenchyma) or the renal arteries. Chronic kidney disease presents initially as microalbuminuria (30-299 mg albumin in a 24-hour urine collection) that can progress to macroalbuminuria and overt kidney failure. The rate of kidney function deterioration is accelerated when both hypertension and diabetes are present. Once patients have an estimated glomerular filtration rate (GFR) of less than 60 mL/m per minute or macroalbuminuria, they have chronic kidney disease, and the risk of cardiovascular disease and progression to severe chronic kidney disease increases. Strict BP control to a goal of less than 130/80 mm Hg can slow the decline in kidney function. This strict control often requires two or more antihypertensive agents. 

Hypertension is the most common cardiovascular disease. Thus, the third National Health and Nutrition Examination Survey (NHANES III), conducted from 1992 to 1994, found that 27% of the USA adult population had hypertension. The prevalence varies with age, race, education, and many other variables. Sustained arterial hypertension damages blood vessels in kidney, heart, and brain and leads to an increased incidence of renal failure, coronary disease, cardiac failure, and stroke. Effective pharmacologic lowering of blood pressure has been shown to prevent damage to blood vessels and to substantially reduce morbidity and mortality rates. Many effective drugs are available. Knowledge of their antihypertensive mechanisms and sites of action allows accurate prediction of efficacy and toxicity. As a result, rational use of these agents, alone or in combination, can lower blood pressure with minimal risk of serious toxicity in most patients. 

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