Rationale and management of hyperlipidemia of the nephrotic syndrome.

Hyperlipidemia is usually present in patients with the nephrotic syndrome. The most common lipid abnormality is hypercholesterolemia, although as the disorder progresses, hypertriglyceridemia may develop. Elevated plasma lipids have two potential vascular consequences, namely, atherosclerosis and progression of renal failure. Neither of these complications has been proven with certainty, but there is growing evidence to indicate that both may be long-term consequences of the nephrotic syndrome. Therefore, effective therapy of hyperlipidemia, particularly elevated cholesterol levels, is needed as a protection against these complications. Since nephrotic hypercholesterolemia frequently is severe, dietary therapy, although a valuable adjunct, will not normalize cholesterol levels in most nephrotic patients. Thus, if effective serum cholesterol lowering is to be achieved, drug therapy will be required. Bile acid-binding resins have been shown to lower cholesterol levels in nephrotic patients, but the decline in cholesterol concentrations is usually insufficient to produce a marked reduction in coronary risk. Nicotinic acid theoretically should be useful for treatment of nephrotic hyperlipidemia, but it has not been adequately tested. The new drugs that inhibit cholesterol synthesis, e.g., lovastatin, appear to be highly promising for treating elevations of both serum cholesterol and triglycerides in the nephrotic syndrome. However, testing of these drugs in this condition has been limited, and the possibility of significant side effects in an appreciable portion of patients has not been ruled out. Of particular concern is the development of severe myopathy that can produce myoglobinuria and acute renal failure. This side effect is relatively rare in patients without the nephrotic syndrome, but its prevalence in the latter condition has not been determined. The fibric acids will lower triglyceride levels in nephrotic patients, but they are not effective in lowering cholesterol levels; consequently, they probably have little role in the treatment of nephrotic hypercholesterolemia. Finally, the drug probucol will lower cholesterol levels in nephrotic patients, although not to desirable levels; still, probucol could prove useful in combination with other cholesterol-lowering drugs.