Mixed hypertriglyceridemia

The principal use of niacin is for mixed hyperlipidemia or as a second-line agent in combination therapy for hypercholesterolemia. It is a first-line agent or alternative for the treatment of hypertriglyceridemia and diabetic dyslipidemia. 

It is indicated as an adjunct to diet to reduce elevated total cholesterol, LDL-cholesterol and TG levels in patients with primary hypercholesterolemia, diabetic dyslipidaemia or mixed hyperlipidemia, hypertriglyceridemia, dysbetalipo-proteinemia and familial hypercholesterolemia. 

Monogenic dyslipoproteinemias can generally be grouped into five categories (1) hypertriglyceridemia with an increase in chylomicrons and the clinical sign of pancreatitis, (2) mixed hyperlipidemia with an increase in chylomicron and VLDL remnants and an increased risk of premature atherosclerosis, (3) hypercholesterolemia with an increase in LDL and an increased risk for premature atherosclerosis, (4) hypoalphalipoproteinemia with low HLD and an increased risk for premature atherosclerosis, and (5) hypolipoproteinemia with a decrease in VLDL and LDL, which may lead to neurological disease. 

Antilipemic stimulates lipoprotein lipase in endothelial cells and peripheral tissues. Used in hypertriglyceridemias and mixed triglyceridemia/hyper-cholesterolemia. Tox GI distress, cholelithiasis, skin rashes. 

In 1967, Fredrickson et al. (9) classified primary hyperlipoproteinemias into six phenotypes (I, Ha, lib. III, IV, and V) based on which lipoproteins and lipids were elevated. Current literature and practice, however, appear to favor the more descriptive classifications and subclassifications listed in Table 30.2 Primary disorders are currently classified as those that primarily cause hypercholesterolemia, those that primarily cause hypertriglyceridemia, and those that cause a mixed elevation of both cholesterol and triglycerides. Subclassifications are based on the specific biochemical defect responsible for the disorder. Classifications developed by Fredrickson have been included in Table 30.2 under the heading Previous Classification for comparative and reference purposes. 

Elevated plasma triglyceride levels can contribute to atherosclerosis and CHD in mixed hyperlipoproteinemias, whereas pure hypertriglyceridemias are primarily associated with pancreatitis and show little to no relationship to CHD (7,8). 

Bile acid sequestrants are indicated for the treatment of hypercholesterolemia in patients who do not adequately respond to dietary modifications. They may be used either alone or in combination with HMGRIs or niacin. These combinations often can achieve a 50% reduction in plasma LDL levels. Cholestyramine, but neither colestipol nor colesevelam, also is approved for the relief of pruritus associated with partial biliary obstruction. Bile acid sequestrants should not be used to treat hypertriglyceridemias or mixed hyperlipoproteinemias in which hypertriglyceridemia is the primary concern. These compounds also are contraindicated in patients with cholelithiasis or complete biliary obstruction because of the impaired secretion of bile acids caused by these conditions. Finally, cholestyramine and colestipol are contraindicated in patients with primary biliary cirrhosis, because this can further raise serum cholesterol (7,15,21). 

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