Colestipol

INDICATIONS & USAGE Since no drug is innocuous, strict attention should be paid to the indications and contraindications, particularly when selecting drugs for chronic long-term use. Colestipol hydrochloride tablets are indicated as adjunctive therapy to diet for the reduction of elevated serum total and LDL-C in patients with primary hypercholesterolemia (elevated LDL-C) who do not respond adequately to diet. Generally, colestipol hydrochloride tablets have no clinically significant effect on serum triglycerides, but with their use, triglyceride levels may be raised in some patients. Therapy with lipid-altering agents should be a component of multiple risk factor intervention in those individuals at significantly increased risk for atherosclerotic vascular disease due to hypercholesterolemia. Treatment should begin and continue with dietary therapy (see NCEP guidelines). A minimum of six months of intensive dietary therapy and counseling should be carried out prior to initiation of drug therapy. Shorter periods may be considered in patients with severe elevations of LDL-C or with definite CHD. According to the NCEP guidelines, the goal of treatment is to lower LDL-C, and LDL-C is to be used to initiate and assess treatment response. Only if LDL-C levels are not available, should the Total-C be used to monitor therapy. The NCEP treatment guidelines are shown below. LDL-Cholesterol mg/dL (mmol/L) Definite Atherosclerotic Disease* Two or More Other Risk Factors** Initiation Level Goal No No ≥190 (≥4.9) <160 (<4.1) No Yes ≥160 (≥4.1) <130 (<3.4) Yes Yes or No ≥130 (≥3.4) ≤100 (≤2.6) * Coronary heart disease or peripheral vascular disease (including symptomatic carotid artery disease). ** Other risk factors for coronary heart disease (CHD) include: age (males: ≥45 years; female: ≥55 years or premature menopause without estrogen replacement therapy); family history of premature CHD; current cigarette smoking; hypertension; confirmed HDL-C <35 mg/dL (0.91 mmol/L); and diabetes mellitus. Subtract one risk factor if HDL-C is ≥60 mg/dL (1.6 mmol/L).

CLINICAL PHARMACOLOGY Cholesterol is the major, and probably the sole precursor of bile acids. During normal digestion, bile acids are secreted via the bile from the liver and gall bladder into the intestines. Bile acids emulsify the fat and lipid materials present in food, thus facilitating absorption. A major portion of the bile acids secreted is reabsorbed from the intestines and returned via the portal circulation to the liver, thus completing the enterohepatic cycle. Only very small amounts of bile acids are found in normal serum. Colestipol hydrochloride binds bile acids in the intestine forming a complex that is excreted in the feces. This nonsystemic action results in a partial removal of the bile acids from the enterohepatic circulation, preventing their reabsorption. Since colestipol hydrochloride is an anion exchange resin, the chloride anions of the resin can be replaced by other anions, usually those with a greater affinity for the resin than the chloride ion. Colestipol hydrochloride is hydrophilic, but it is virtually water insoluble (99.75%) and it is not hydrolyzed by digestive enzymes. The high molecular weight polymer in colestipol hydrochloride apparently is not absorbed. In humans, less than 0.17% of a single 14 C-labeled colestipol hydrochloride dose is excreted in the urine when given following 60 days of dosing of 20 grams of colestipol hydrochloride per day. The increased fecal loss of bile acids due to colestipol hydrochloride administration leads to an increased oxidation of cholesterol to bile acids. This results in an increase in the number of low-density lipoprotein (LDL) receptors, increased hepatic uptake of LDL and a decrease in beta lipoprotein or LDL serum levels, and a decrease in serum cholesterol levels. Although colestipol hydrochloride produces an increase in the hepatic synthesis of cholesterol in man, serum cholesterol levels fall. There is evidence to show that this fall in cholesterol is secondary to an increased rate of clearance of cholesterol-rich lipoproteins (beta or low-density lipoproteins) from the plasma. Serum triglyceride levels may increase or remain unchanged in colestipol hydrochloride treated patients. The decline in serum cholesterol levels with colestipol hydrochloride treatment is usually evident by one month. When colestipol hydrochloride is discontinued, serum cholesterol levels usually return to baseline levels within one month. Periodic determinations of serum cholesterol levels as outlined in the National Cholesterol Education Program (NCEP) guidelines, should be done to confirm a favorable initial and long-term response 1 . In a large, placebo-controlled, multiclinic study, the LRC-CPPT 2 , hypercholesterolemic subjects treated with cholestyramine, a bile-acid sequestrant with a mechanism of action and an effect on serum cholesterol similar to that of colestipol hydrochloride, had reductions in total and LDL-C. Over the 7-year study period the cholestyramine group experienced a 1

DOSAGE & ADMINISTRATION For adults, colestipol hydrochloride tablets are recommended in doses of 2 to 16 grams/day given once or in divided doses. The starting dose should be 2 grams once or twice daily. Dosage increases of 2 grams, once or twice daily should occur at 1-or 2-month intervals. Appropriate use of lipid profiles as per NCEP guidelines including LDL-C and triglycerides, is advised so that optimal but not excessive doses are used to obtain the desired therapeutic effect on LDL-C level. If the desired therapeutic effect is not obtained at a dose of 2 to 16 grams/day with good compliance and acceptable side effects, combined therapy or alternate treatment should be considered. Colestipol hydrochloride tablets must be taken one at a time and be promptly swallowed whole, using plenty of water or other appropriate liquid. Do not cut, crush, or chew the tablets. Patients should take other drugs at least one hour before or four hours after colestipol hydrochloride tablets to minimize possible interference with their absorption. (See Drug Interactions.) Before Administration of Colestipol Hydrochloride Tablets Define the type of hyperlipoproteinemia, as described in NCEP guidelines. Institute a trial of diet and weight reduction. Establish baseline serum total and LDL-C and triglyceride levels. During Administration of Colestipol Hydrochloride Tablets The patient should be carefully monitored clinically, including serum cholesterol and triglyceride levels. Periodic determinations of serum cholesterol levels as outlined in the NCEP guidelines should be done to confirm a favorable initial and long-term response. Failure of total or LDL-C to fall within the desired range should lead one to first examine dietary and drug compliance. If these are deemed acceptable, combined therapy or alternate treatment should be considered. Significant rise in triglyceride level should be considered as indication for dose reduction, drug discontinuation, or combined or alternate therapy.

ADVERSE REACTIONS Gastrointestinal The most common adverse reactions are confined to the gastrointestinal tract. To achieve minimal GI disturbance with an optimal LDL-C lowering effect, a gradual increase of dosage starting with 2 grams, once or twice daily is recommended. Constipation is the major single complaint and at times is severe. Most instances of constipation are mild, transient, and controlled with standard treatment. Increased fluid intake and inclusion of additional dietary fiber should be the first step; a stool softener may be added if needed. Some patients require decreased dosage or discontinuation of therapy. Hemorrhoids may be aggravated. Other, less frequent gastrointestinal complaints consist of abdominal discomfort (abdominal pain and cramping), intestinal gas (bloating and flatulence), indigestion and heartburn, diarrhea and loose stools, and nausea and vomiting. Bleeding hemorrhoids and blood in the stool have been infrequently reported. Peptic ulceration, cholecystitis, and cholelithiasis have been rarely reported in patients receiving colestipol hydrochloride granules, and are not necessarily drug related. Difficulty swallowing and transient esophageal obstruction have been rarely reported in patients taking colestipol hydrochloride tablets. Transient and modest elevations of aspartate aminotransferase (AST, SGOT), alanine aminotransferase (ALT, SGPT) and alkaline phosphatase were observed on one or more occasions in various patients treated with colestipol hydrochloride. The following nongastrointestinal adverse reactions have been reported with generally equal frequency in patients receiving colestipol hydrochloride tablets, colestipol granules, or placebo in clinical studies: Cardiovascular Chest pain, angina, and tachycardia have been infrequently reported. Hypersensitivity Rash has been infrequently reported. Urticaria and dermatitis have been rarely noted in patients receiving colestipol hydrochloride granules. Musculoskeletal Musculoskeletal pain, aches and pains in the extremities, joint pain and arthritis, and backache have been reported. Neurologic Headache, migraine headache, and sinus headache have been reported. Other infrequently reported complaints include dizziness, light-headedness, and insomnia. Miscellaneous Anorexia, fatigue, weakness, shortness of breath, and swelling of the hands or feet, have been infrequently reported. To report SUSPECTED ADVERSE REACTIONS, contact Edenbridge Pharmaceuticals at 1-877-381-3336 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

CONTRAINDICATIONS Colestipol hydrochloride tablets are contraindicated in those individuals who have shown hypersensitivity to any of their components.

OVERDOSAGE Overdosage of colestipol hydrochloride tablets has not been reported. Should overdosage occur, however, the chief potential harm would be obstruction of the gastrointestinal tract. The location of such potential obstruction, the degree of obstruction and the presence or absence of normal gut motility would determine treatment.