Comparison of the effects of colestipol hydrochloride and clofibrate on plasma lipids and lipoproteins in the treatment of hypercholesterolemia

Efficacy and safety of high-density lipoprotein cholesterol-increasing compounds: a meta-analysis of randomized controlled trials

OBJECTIVES

The aim of this research was to estimate the efficacy and safety of current high-density lipoprotein cholesterol (HDL-C)-increasing drugs.

BACKGROUND

Epidemiologic evidence has shown that HDL-C is inversely related to coronary heart disease (CHD) risk. However, the evidence for reducing CHD risk by raising HDL-C is thin, predominantly due to the paucity of effective and safe HDL-increasing drugs.

METHODS

Randomized controlled trials with fibrates and niacin, published between 1966 through February 2004 (MEDLINE), were retrieved. Information on treatment, baseline characteristics, serum lipids, end points, and side-effects were independently abstracted by two authors using a standardized protocol.

RESULTS

Data from 53 trials (16,802 subjects) using fibrates and 30 trials (4,749 subjects) using niacin were included. Random-effects model showed 11% versus 10% reduction in total cholesterol, 36% versus 20% reduction in triglycerides, 8% versus 14% reduction in low-density lipoprotein cholesterol, and 10% versus 16% increase in HDL-C for fibrates and niacin, respectively. Apart from flushes in the niacin group, both fibrates and niacin were shown to be well-tolerated and safe. Fibrates reduced the risk for major coronary events by 25% (95% confidence interval 10% to 38%), whereas current available data for niacin indicate a 27% reduction.

CONCLUSIONS

Fibrates reduce major coronary events and increase HDL-C levels without significant toxicity. Niacin has a more potent effect on HDL-C levels, whereas data on cardiovascular event rate reduction are limited. Future studies need to evaluate whether additional HDL increase by fibrates or particularly newer niacin formulations on top of statin therapy translates into further event reduction in high-risk subjects, without significant toxicity.

Effect of fibric acid derivatives on blood lipid and lipoprotein levels

The literature for the last seven years was reviewed in terms of the effect of the various fibric acid derivatives on blood lipid and lipoprotein levels. The criteria for review resulted in a greater focus on three of the newer fibric acid derivatives: bezafibrate, ciprofibrate, fenofibrate. In type II A hyperlipoproteinemia, all fibric acid derivatives produce modest reductions in total plasma cholesterol and low-density lipoprotein cholesterol. The evidence suggests that bezafibrate, ciprofibrate, and fenofibrate may produce greater reductions in low-density lipoprotein cholesterol than those usually observed with clofibrate and gemfibrozil. All fibric acid derivatives produce modest reductions in triglycerides and modest increases in high-density lipoprotein cholesterol in type II A hyperlipoproteinemia. In type II B hyperlipoproteinemia, the low-density lipoprotein cholesterol lowering effect of fibric acid derivatives is generally less than that observed in type II A hyperlipoproteinemia. In type II B hyperlipoproteinemia, there is a mean decrease in low-density lipoprotein cholesterol for all patients studied. However, there is a considerable interpatient variation ranging from significant decreases to significant increases in low-density lipoprotein cholesterol. Further studies are required to assess whether the low-density lipoprotein cholesterol lowering effect is greater with the newer fibric acid derivatives. All fibric acid derivatives produce clinically significant decreases in triglyceride levels in type II B. There is also an associated increase in high-density lipoprotein cholesterol. In type IV hyperlipoproteinemia, all fibric acid derivatives produce clinically significant reductions in triglyceride. There is also an associated increase in high-density lipoprotein cholesterol and generally also an increase in low-density lipoprotein cholesterol levels. The available data do not suggest a clinically significant difference in the hypotriglyceridemic effect of the various fibric acid derivatives in type IV hyperlipoproteinemia. The lipid-altering effects of the various fibric acid derivatives were usually less in those studies that contained placebo and dietary controls. Additional controlled clinical trials are needed to accurately discriminate the relative lipid-and lipoprotein-altering effects of the various fibric acid derivatives.

The effects of colestipol hydrochloride on serum lipoprotein lipid and apolipoprotein B and A-I concentrations in children heterozygous for familial hypercholesterolemia

The effects of colestipol hydrochloride on serum lipoprotein lipid and apolipoprotein B and A-I concentrations in children heterozygous for familial hypercholesterolemia. Acta Paediatr Scand, 72:81, 1983.--Colestipol hydrochloride was administered to 28 children with familial hypercholesterolemia type II-A, and its effects on serum lipoproteins were tested against a placebo in a cross-over design. All children consumed a diet low in cholesterol and high in linoleic acid. Colestipol therapy resulted in a 15.7% decrease in serum very low plus low density lipoproteins and in a 13.5% decrease in serum apolipoprotein B. High density lipoprotein cholesterol, serum apolipoprotein A-I and serum triglycerides remained unaltered.

Ciprofibrate in the therapy of type II hypercholesterolemia. A double-blind trial

The hypolipidemic efficacy of ciprofibrate was evaluated in patients with type II hypercholesterolemia. Patients were randomized to placebo or ciprofibrate (50 mg or 100 mg/day) and, after a 6-week baseline period, received medication for a period of 12 weeks. Blood samples were analyzed every 2 weeks. Twenty patients completed the study (4 on placebo, 7 on 50 mg/day, and 9 on 100 mg/day ciprofibrate). The drug was well tolerated in all patients. Lipid values in the patients on active drug decreased and attained stable values after 4 weeks of treatment. Compared to baseline values, total and LDL cholesterol decreased 11% and 13% on the 50-mg dose whereas HDL increased 8%. Plasma triglyceride fell by 22%. In patients receiving 100 mg ciprofibrate, total and LDL cholesterol fell by 20% (334 leads to 269 mg/dl) and 24% (262 leads to 198 mg/dl), respectively. HDL increased 9.8% (51 leads to 56 mg/dl) and triglyceride decreased by 30% (102 leads to 69 mg/dl). Values in the placebo group remained stable. We conclude that once daily therapy with 100 mg ciprofibrate, is effective in reducing LDL levels in patients with type II hypercholesterolemia (mainly heterozygous FH) and that this decrease is paralleled by small rises in HDL.

Regulation of high density lipoprotein levels

Current concepts of the structure and metabolism of high density lipoproteins are presented and factors that influence their levels in human beings are surveyed.