Cholesterol-lowering effect of colestipol hydrochloride given twice daily in hypercholesterolemic patients

Systematic review on the risk and benefit of different cholesterol-lowering interventions

Meta-analyses have investigated the efficacy of cholesterol-lowering interventions in relation to the underlying risk of coronary heart disease and the extent and duration of cholesterol reduction. We systematically reviewed the efficacy of antilipidemic interventions on major mortality outcomes in relation to drug classes. We searched MEDLINE and EMBASE from 1966 through October 1996 for randomized, controlled trials of any cholesterol-lowering interventions reporting mortality data. We included 59 trials involving 85 431 participants in the intervention and 87 729 participants in the control groups. We pooled these trials into 7 pharmacological categories of cholesterol-lowering interventions: statins (13 trials), fibrates (12 trials), resins (8 trials), hormones (8 trials), niacin acid (2 trials), n-3 fatty acids (3 trials), and dietary interventions (16 trials). Of the cholesterol-lowering interventions, only statins showed a large and statistically significant reduction in mortality from coronary heart disease (risk ratio, 0.66; 95% confidence interval [CI], 0.54 to 0. 79) and from all causes (risk ratio, 0.75; 95% CI, 0.65 to 0.86). For both all-cause and cardiovascular mortality, the difference between statins and the combined estimate of the other classes of agents was unlikely to be due to chance (P<0.02 for both comparisons). Meta-regression analysis demonstrated that variability in results across trials could be largely explained on the basis of differences in the magnitude of cholesterol reduction. Statins have the largest effect on the reduction of cardiovascular and all-cause mortality, and this result recommends their use in preference to other antilipidemic agents. The greater effect of statins is likely due to the larger reduction in cholesterol.

Reduced LDL- and increased HDL-apoproteins in patients with hypercholesterolaemia under treatment with bezafibrate

The effect of bezafibrate on serum lipids, lipoproteins and the apoproteins A-I, A-II and B was studied in 18 patients with primary hypercholesterolaemia. Total cholesterol was lowered by 20% (P less than 0.05), LDL-cholesterol by 24% (P less than 0.05), and apo B by 14% (P less than 0.05), which is comparable to the effect obtained with anion exchange resins but with far fewer side-effects. HDL increased significantly during bezafibrate treatment both by measurement of HDL-cholesterol (+54%, P less than 0.05) and by the determination of HDL-apoproteins A-I (+ 19%, P less than 0.05) and A-II (+ 23%, P less than 0.05). This increase of HDL and the decrease of triglycerides was maintained for 6 weeks of placebo treatment after cessation of bezafibrate, while serum total and LDL cholesterol as well as apo B returned to their baseline levels.

Effect of colestipol and clofibrate, singly and in combination, on plasma lipid and lipoproteins in type IIb hyperlipoproteinemia

The effect of colestipol, clofibrate and a combination of these two drugs on plasma lipid and lipoprotein levels was evaluated in 14 adult male patients with Type IIb hyperlipoproteinemia. A crossover design with each patient receiving all three treatments was utilized. Twenty g of colestipol per day reduced total and LDL cholesterol by 39.1 and 51.5 mg/dl, respectively (p less than 0.001). There was an associated rise in total triglycerides of 63.5 mg/dl (p less than 0.01) with no significant change in HDL cholesterol. Clofibrate, 2.0 g per day, did not significantly lower either total (-7.9 mg/dl) or LDL cholesterol (+8.7 mg/dl). There was marked interpatient variability in terms of the LDL cholesterol response to clofibrate, but the majority of patients demonstrated an increase. HDL cholesterol levels increased by 6.7 mg/dl (p less than 0.01) and total triglycerides were reduced by 94.6 mg/dl (p less than 0.001). Utilizing the same dosages of both drugs, the combination of colestipol and clofibrate were less effective in lowering total and LDL cholesterol than colestipol therapy alone, and increases in HDL cholesterol and decreases in triglycerides similar to those obtained with clofibrate were observed.

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

The effects of colestipol HCl resin and clofibrate on plasma lipid and lipoprotein levels were compared in 65 patients with primary hypercholesterolemia. Patients were randomly assigned to treatment with colestipol (in progressive doses of 15, 20, and 30 g/day), clofibrate (2 g/day), or placebo resin; lipoprotein levels were determined at months 0, 2, 4, 6, and 9. The colestipol group received both colestipol and clofibrate during months 7 through 9 of the study. After 6 months of treatment, mean plasma total cholesterol fell from 333 to 266 (P less than 0.01) on colestipol, and from 329 to 270 (P less than 0.05) on clofibrate. More patients responded, however, to colestipol than to clofibrate. Both drugs also produced significant reductions in LDL cholesterol levels, and clofibrate lowered plasma triglycerides as well. HDL cholesterol level did not change significantly on either medication. The placebo group showed no change in any of the parameters studied. A significant difference was not observed between the effects of 15 g/day of colestipol and those of the higher doses studies. Addition of clofibrate to colestipol did not enhance the latter's hypocholesterolemic action.

The effects of colestipol when combined with clofibrate in the treatment of severe hyperlipidemia. Short-term and long-term studies

Twenty-two patients suffering from hyperlipidemia and receiving therapy consisting of a lipid-lowering diet and clofibrate (1 g X 2) were in addition given colestipol hydrochloride (5 g X 3) (Colestid, Upjohn) in a randomized, cross-over study for 2 periods of 6 weeks. Both the cholesterol and the triglyceride concentrations in very low density lipoproteins remained unchanged during the colestipol treatment. The cholesterol concentration in low density lipoproteins decreased by 23% (P < 0.001) and increased in high density lipoproteins by 4% (P < 0.01). In a second part of the project, the effects on the lipoprotein lipids of 15 g of colestipol divided into 1, 2 or 3 daily doses were studied when added to ongoing therapy with clofibrate (1 g X 2) and lipid-lowering diet. When the colespitol was divided into 2 or 3 daily doses, the effects were manifested equally but were less pronounced when 1 dose per day was given. In a third study, 14 patients who were treated with a combination of lipid-lowering diet, clofibrate (1 g X 2) and colestipol hydrochloride (15 g daily) were followed over a 2-year period, during which time the serum cholesterol and triglyceride concentrations were maintained at a reduced level. The fasting blood glucose and serum insulin concentrations were increased during colestipol treatment. Such treatment should therefore not be given to patients with impaired glucose tolerance.

Colestipol: a review of its pharmacological properties and therapeutic efficacy in patients with hypercholesterolaemia

Colestipol is an anion exchange resin with bile acid sequestering properties resembling those of cholestyramine, another lipid-lowering binding resin. In daily doses of 15 to 30g colestipol reduces total plasma cholesterol concentrations (primarily low density lipoprotein cholesterol) by about 15 to 30%, but plasma triglyceride concentrations may be unchanged or in some patients increased. Thus, like cholestyramine, colestipol is of benefit in patients with primary hypercholesterolaemia without associated hypertriglyceridaemia (type IIa hyperlipoproteinaemia). Colestipol is odourless and tasteless, and is said by some to be more readily tolerated by patients than cholestyramine, leading to improved compliance, but such data has not been documented in most studies. Side effects of colestipol treatment are primarily gastrointestinal in nature since the drug is essentially unabsorbed. As with cholestyramine, colestipol may bind with other concomitantly administered drugs reducing their absorption or enterohepatic recirculation; dosage intervals of other concurrent medications should be adjusted to minimise the potential for such an interaction.

Use of combined diet and colestipol in long-term (7--7 1/2 years) treatment of patients with type II hyperlipoproteinemia

Long-term effects of diet and colestipol (a bile acid sequestrant) were studied in 25 patients with familial type II hyperlipoproteinemia. Serum lipids and body weights of an initial group of 30 patients were stabilized by low cholesterol-saturated fat-refined carbohydrate diet and the patients were then randomized into placebo and drug-treatment groups. After explaining that the drug is nontoxic and effective in lowering serum lipids, total cholesterol (C) and low-density lipoprotein cholesterol (LDL-C), colestipol (30 g/day) and diet were given to the 25 patients who remained in the long-term follow-up program. The treatment resulted in highly significant lowering of serum lipids (mg/dl, mean +/- SEM): C and LDL-C from 412.7 +/- 24.4 and 331.1 +/- 22.8 to 270 +/- 11.0 and 188.1 +/- 13.8, respectively (p less than 0.001 in each instance) over 7--7 1/2 years. Although we observed no absolute increase in high density lipoprotein (HDL), the HDL/LDL ratio was elevated. Long-term colestipol and diet treatment reduced the xanthoma size and stabilized serially angiographically visualized atherosclerotic lesions in 21 of the 25 patients who showed a satisfactory hypolipemic response. It did not cause nutritional or metabolic disturbances.

Abnormal low density lipoproteins in children with familial hypercholesterolemia--effect of polyanion exchange resins

In 20 children and adolescents with familial Type II a hyperlipoproteinemia, serum lipids and lipoproteins were examined before and during treatment with polyanion exchange resins. The composition of LDL was compared to that of helthy siblings. The patients were given Colestyramine (0.6 g/kg body weight) and Colestipol (0.5 g/kg body weight) in a cross-over study for 8 weeks each, after they had been under dietary treatment for at least 12 months. In 6 children, drug treatment had to be stopped due to side-effects. The most common complaints were gastrointestinal discomfort and constipation. Cholesterol, triglycerides and phopholipids were measured in whole serum and cholesterol, triglycerides and Apolipoprotein-B in isolated lipoprotein fractions after ultracentrifugation. Apo-B was determined by radial immunodiffusion. The Apo-B: cholesterol ratio in whole serum and in the LDL fraction was identical in the patients and in the controls. The LDL triglyceride: Apo-B ratio, however, was about 50% lower in the patients. This abnormal LDL composition was not altered by therapy with polyanion exchange resins. HDL cholesterol levels were significantly lower in the patients than in healthy children, and remained low during therapy. The decrease of total and LDL cholesterol (25%) and Apo-B (20%) was similar under both Colestipol and Colestyramine. Triglycerides and phospholipids showed no significant changes in therapy.