Comparison of calcium channel blocker and ACE inhibitor therapy on the progression of renal insufficiency

Dosing of antihypertensive medications in patients with renal insufficiency

The use of antihypertensive agents in patients with renal insufficiency necessitates careful consideration of dosages, titration, and monitoring. Renal function must be estimated to appropriately make dosage adjustments for antihypertensives that exhibit extensive renal elimination. Thiazide diuretics are useful in mild degrees of renal insufficiency but loop diuretics become necessary as renal function deteriorates further. With either class, low dosages should be used to prevent hypovolemia, hyponatremia, and hypokalemia which may worsen renal blood flow. Angiotensin-converting enzyme (ACE) inhibitors have become popular because they may have unique renal protective properties. All ACE inhibitors except fosinopril require reduced dosages and/or less frequent administration in patients with renal insufficiency. It is often necessary to use a diuretic with an ACE inhibitor and special dosing considerations are important. Due to demographic and physiologic characteristics of patients with renal insufficiency, beta blockers are often reserved for patients with other indications for beta blockers such as ischemic heart disease. Several beta blockers are eliminated primarily by the kidney and dosage reductions are necessary for these agents. Calcium antagonists may also have renal protective effects. Because calcium antagonists are metabolized extensively, significant dosage adjustments are not necessary. Data suggest that antihypertensives may slow the decline in renal insufficiency. The pharmacokinetics of several antihypertensives change with renal impairment because of reduced elimination. Therefore, dosage adjustments, slower titration, and less frequent administration are often necessary.

Hypertension and endstage renal disease

OBJECTIVE

To review current literature regarding the development of hypertensive renal disease, its epidemiology, and its pathophysiology. This review focuses on strategies to slow or halt the progression of endstage renal disease (ESRD) in hypertension, including the role of blood pressure control, different types of antihypertensive agents, early treatment, and dietary considerations.

DATA SOURCES

Information was retrieved from searching the MEDLINE database for articles consisting of epidemiologic studies, clinical studies, and review articles pertaining to hypertension and ESRD. Information also was obtained from the US Renal Data System annual data reports.

STUDY SELECTION

Emphasis was placed on clinical trials in the English language addressing issues in hypertension and ESRD. Clinical trials reporting relationships between blood pressure control and ESRD, as well as those comparing different antihypertensive agents, were evaluated.

DATA EXTRACTION

The methodology and results from clinical trials were evaluated. Studies were assessed according to the measures of renal function used, baseline data collected, degree of blood pressure control, and antihypertensive therapy.

DATA SYNTHESIS

Clinical trials including patients with essential hypertension, diabetes mellitus, and renal insufficiency of various etiologies were evaluated. The recommendations from these evaluations were based on study design and the types of populations used (i.e., blacks vs. whites, diabetics vs. nondiabetics).

CONCLUSIONS

Blood pressure control is currently the most important strategy to slow or halt the progression of renal insufficiency in hypertensive individuals. Whether specific antihypertensives are renal protective is still controversial, but results from clinical trials are promising.