QUESTRAN ® (Cholestyramine for Oral Suspension USP), the chloride salt of a basic anion exchange resin, a cholesterol lowering agent, is intended for oral administration. Cholestyramine resin is quite hydrophilic, but insoluble in water. The cholestyramine resin in QUESTRAN is not absorbed from the digestive tract. Four grams of anhydrous cholestyramine resin is contained in 9 grams of QUESTRAN powder. Four grams of anhydrous cholestyramine resin is contained in 5 grams of QUESTRAN LIGHT. It is represented by the following structural formula:

Cholesterol is probably the sole precursor of bile acids. During normal digestion, bile acids are secreted into the intestines. A major portion of the bile acids is absorbed from the intestinal tract and returned to the liver via the enterohepatic circulation. Only very small amounts of bile acids are found in normal serum.

QUESTRAN resin adsorbs and combines with the bile acids in the intestine to form an insoluble complex which is excreted in the feces. This results in a partial removal of bile acids from the enterohepatic circulation by preventing their absorption.

The increased fecal loss of bile acids due to QUESTRAN administration leads to an increased oxidation of cholesterol to bile acids, a decrease in beta lipoprotein or low density lipoprotein plasma levels and a decrease in serum cholesterol levels. Although in man, QUESTRAN produces an increase in hepatic synthesis of cholesterol, plasma cholesterol levels fall.

In patients with partial biliary obstruction, the reduction of serum bile acid levels by QUESTRAN reduces excess bile acids deposited in the dermal tissue with resultant decrease in pruritus.

QUESTRAN (Cholestyramine for Oral Suspension USP) contains the following inactive ingredients: acacia, citric acid, D&C Yellow No. 10, FD&C Yellow No. 6, flavor (natural and artificial Orange), polysorbate 80, propylene glycol alginate and sucrose. QUESTRAN LIGHT (Cholestyramine for Oral Suspension USP, Light) contains the following inactive ingredients: aspartame, citric acid, colloidal silicon dioxide, D&C Yellow No. 10, FD&C Red No. 40, flavor (natural and artificial Orange), maltodextrin, propylene glycol alginate and xanthan gum.

Cholesterol is probably the sole precursor of bile acids. During normal digestion, bile acids are secreted into the intestines. A major portion of the bile acids is absorbed from the intestinal tract and returned to the liver via the enterohepatic circulation. Only very small amounts of bile acids are found in normal serum.

Cholestyramine resin adsorbs and combines with the bile acids in the intestine to form an insoluble complex which is excreted in the feces. This results in a partial removal of bile acids from the enterohepatic circulation by preventing their absorption.

The increased fecal loss of bile acids due to Cholestyramine administration leads to an increased oxidation of cholesterol to bile acids, a decrease in beta lipoprotein or low density lipoprotein plasma levels and a decrease in serum cholesterol levels. Although in man, Cholestyramine produces an increase in hepatic synthesis of cholesterol, plasma cholesterol levels fall.

In patients with partial biliary obstruction, the reduction of serum bile acid levels by Cholestyramine reduces excess bile acids deposited in the dermal tissue with resultant decrease in pruritus.

1) QUESTRAN (Cholestyramine for Oral Suspension USP), is indicated as adjunctive therapy to diet for the reduction of elevated serum cholesterol in patients with primary hypercholesterolemia (elevated low density lipoprotein [LDL] cholesterol) who do not respond adequately to diet. QUESTRAN may be useful to lower LDL cholesterol in patients who also have hypertriglyceridemia, but it is not indicated where hypertriglyceridemia is the abnormality of most concern.

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 specific for the type of hyperlipoproteinemia determined prior to initiation of drug therapy. Excess body weight may be an important factor and caloric restriction for weight normalization should be addressed prior to drug therapy in the overweight.

Prior to initiating therapy with QUESTRAN, secondary causes of hypercholesterolemia (e.g., poorly controlled diabetes mellitus, hypothyroidism, nephrotic syndrome, dysproteinemias, obstructive liver disease, other drug therapy, alcoholism), should be excluded, and a lipid profile performed to assess Total cholesterol, HDL-C, and triglycerides (TG). For individuals with TG less than 400 mg/dL (<4.5 mmol/L), LDL-C can be estimated using the following equation:

LDL-C = Total cholesterol – [(TG/5) + HDL-C]

For TG levels >400 mg/dL, this equation is less accurate and LDL-C concentrations should be determined by ultracentrifugation. In hypertriglyceridemic patients, LDL-C may be low or normal despite elevated Total-C. In such cases QUESTRAN may not be indicated.

Serum cholesterol and triglyceride levels should be determined periodically based on NCEP guidelines to confirm initial and adequate long-term response. A favorable trend in cholesterol reduction should occur during the first month of QUESTRAN therapy. The therapy should be continued to sustain cholesterol reduction. If adequate cholesterol reduction is not attained, increasing the dosage of QUESTRAN or adding other lipid-lowering agents in combination with QUESTRAN should be considered.

Since the goal of treatment is to lower LDL-C, the NCEP 4 recommends that LDL-C levels be used to initiate and assess treatment response. If LDL-C levels are not available then Total-C alone may be used to monitor long-term therapy. A lipoprotein analysis (including LDL-C determination) should be carried out once a year. The NCEP treatment guidelines are summarized below.

1) QUESTRAN monotherapy has been demonstrated to retard the rate of progression 2,3 and increase the rate of regression3 of coronary atherosclerosis.

2) QUESTRAN is indicated for the relief of pruritus associated with partial biliary obstruction. QUESTRAN for oral suspension has been shown to have a variable effect on serum cholesterol in these patients. Patients with primary biliary cirrhosis may exhibit an elevated cholesterol as part of their disease.

QUESTRAN is contraindicated in patients with complete biliary obstruction where bile is not secreted into the intestine and in those individuals who have shown hypersensitivity to any of its components.

PHENYLKETONURICS: CHOLESTYRAMINE for ORAL SUSPENSION USP, LIGHT CONTAINS 14.0 mg PHENYLALANINE PER 5 GRAM DOSE.

The most common adverse reaction is constipation. When used as a cholesterol-lowering agent predisposing factors for most complaints of constipation are high dose and increased age (more than 60 years old). Most instances of constipation are mild, transient, and controlled with conventional therapy. Some patients require a temporary decrease in dosage or discontinuation of therapy.

Less Frequent Adverse Reactions: Abdominal discomfort and/or pain, flatulence, nausea, vomiting, diarrhea, eructation, anorexia, and steatorrhea, bleeding tendencies due to hypoprothrombinemia (Vitamin K deficiency) as well as Vitamin A (one case of night blindness reported) and D deficiencies, hyperchloremic acidosis in children, osteoporosis, rash and irritation of the skin, tongue and perianal area. Rare reports of intestinal obstruction, including two deaths, have been reported in pediatric patients.

Occasional calcified material has been observed in the biliary tree, including calcification of the gallbladder, in patients to whom QUESTRAN has been given. However, this may be a manifestation of the liver disease and not drug related.

One patient experienced biliary colic on each of three occasions on which he took QUESTRAN. One patient diagnosed as acute abdominal symptom complex was found to have a “pasty mass” in the transverse colon on x-ray.

Other events (not necessarily drug related) reported in patients taking QUESTRAN include:

Gastrointestinal—GI-rectal bleeding, black stools, hemorrhoidal bleeding, bleeding from known duodenal ulcer, dysphagia, hiccups, ulcer attack, sour taste, pancreatitis, rectal pain, diverticulitis.

Laboratory test changes—Liver function abnormalities.

Hematologic—Prolonged prothrombin time, ecchymosis, anemia

Hypersensitivity—Urticaria, asthma, wheezing, shortness of breath.

Musculoskeletal—Backache, muscle and joint pains, arthritis.

Neurologic—Headache, anxiety, vertigo, dizziness, fatigue, tinnitus, syncope, drowsiness, femoral nerve pain, paresthesia.

Eye—Uveitis.

Renal—Hematuria, dysuria, burnt odor to urine, diuresis.

Miscellaneous—Weight loss, weight gain, increased libido, swollen glands, edema, dental bleeding, dental caries, erosion of tooth enamel, tooth discoloration.

Overdosage with QUESTRAN has been reported in a patient taking 150% of the maximum recommended daily dosage for a period of several weeks. No ill effects were reported. Should an overdosage occur, 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.

The recommended starting adult dose for all QUESTRAN powdered products (QUESTRAN Powder and QUESTRAN Light) is one packet or one level scoopful once or twice a day. The recommended maintenance dose for all QUESTRAN powdered products is 2 to 4 packets or scoopfuls daily (8-16 grams anhydrous cholestyramine resin) divided into two doses. Four grams of anhydrous cholestyramine resin is contained in each measured dose of QUESTRAN as follows:

It is recommended that increases in dose be gradual with periodic assessment of lipid/lipoprotein levels at intervals of not less than 4 weeks. The maximum recommended daily dose is six packets or scoopfuls of QUESTRAN (24 grams of anhydrous cholestyramine resin). The suggested time of administration is at mealtime but may be modified to avoid interference with absorption of other medications. Although the recommended dosing schedule is twice daily, QUESTRAN may be administered in 1–6 doses per day.

QUESTRAN should not be taken in its dry form. Always mix QUESTRAN with water or other fluids before ingesting. See Preparation Instructions.

QUESTRAN ® Powder (Cholestyramine for Oral Suspension USP) is available in cans containing 378 grams and in cartons of sixty 9 gram packets. Four grams of anhydrous cholestyramine resin are contained in 9 grams of QUESTRAN Powder. The 378 g can includes a 15 cc scoop. The scoop is not interchangeable with scoops from other products.

QUESTRAN ® LIGHT (Cholestyramine for Oral Suspension USP), Light is available in cans containing 210 grams and in cartons of sixty 5 gram packets. Four grams of anhydrous cholestyramine resin are contained in 5 grams of QUESTRAN LIGHT. The 210 g can includes a 9 cc scoop. The scoop is not interchangeable with scoops from other products.

In a large, placebo-controlled, multi-clinic study, LRC-CPPT 1, hypercholesterolemic subjects treated with QUESTRAN had mean reductions in total and low-density lipoprotein cholesterol (LDL-C) which exceeded those for diet and placebo treatment by 7.2% and 10.4%, respectively. Over the seven-year study period the QUESTRAN group experienced a 19% reduction (relative to the incidence in the placebo group) in the combined rate of coronary heart disease death plus non-fatal myocardial infarction (cumulative incidences of 7% QUESTRAN and 8.6% placebo). The subjects included in the study were men aged 35 - 59 with serum cholesterol levels above 265 mg/dL and no previous history of heart disease. It is not clear to what extent these findings can be extrapolated to females and other segments of the hypercholesterolemic population. (See also PRECAUTIONS: Carcinogenesis, Mutagenesis, Impairment of Fertility.)

Two controlled clinical trials have examined the effects of QUESTRAN monotherapy upon coronary atherosclerotic lesions using coronary arteriography. In the NHLBI Type II Coronary Intervention Trial 2, 116 patients (80% male) with coronary artery disease (CAD) documented by arteriography were randomized to QUESTRAN or placebo for five years of treatment. Final study arteriography revealed progression of coronary artery disease in 49% of placebo patients compared to 32% of the QUESTRAN group (p<0.05).

In the St. Thomas Atherosclerosis Regression Study (STARS) 3, 90 hypercholesterolemic men with CAD were randomized to three blinded treatments: usual care, lipid-lowering diet, and lipid-lowering diet plus QUESTRAN. After 36 months, follow-up coronary arteriography revealed progression of disease in 46% of usual care patients, 15% of patients on lipid-lowering diet and 12% of those receiving diet plus QUESTRAN (p<0.02). The mean absolute width of coronary segments decreased in the usual care group, increased slightly (0.003mm) in the diet group and increased by 0.103mm in the diet plus QUESTRAN group (p<0.05). Thus in these randomized controlled clinical trials using coronary arteriography, QUESTRAN monotherapy has been demonstrated to slow progression 2,3 and promote regression3 of atherosclerotic lesions in the coronary arteries of patients with coronary artery disease.

The effect of intensive lipid-lowering therapy on coronary atherosclerosis has been assessed by arteriography in hyperlipidemic patients. In these randomized, controlled clinical trials, patients were treated for two to four years by either conventional measures (diet, placebo, or in some cases low dose resin), or intensive combination therapy using diet plus colestipol (an anion exchange resin with a mechanism of action and an effect on serum lipids similar to that of QUESTRAN and QUESTRAN LIGHT) plus either nicotinic acid or lovastatin. When compared to conventional measures, intensive lipid-lowering combination therapy significantly reduced the frequency of progression and increased the frequency of regression of coronary atherosclerotic lesions in patients with or at risk for coronary artery disease.

• •The Lipid Research Clinics Coronary Primary Prevention Trial Results: (I) Reduction in Incidence of Coronary Heart Disease; (II) The Relationship of Reduction in Incidence of Coronary Heart Disease to Cholesterol Lowering. JAMA 1984; 251:351-374.
• •Brensike JF, Levy RI, Kelsey SF, et al. Effects of therapy with cholestyramine on progression of coronary arteriosclerosis: results of the NHLBI type II coronary intervention study. Circulation 1984;69:313-24.
• •Watts, GF, Lewis B, Brunt JNH, Lewis ES, et al. Effects on coronary artery disease of lipid-lowering diet, or diet plus cholestyramine, in the St Thomas Atherosclerosis Regression Study (STARS). Lancet 1992;339:563-69.
• •National Cholesterol Education Program. Second Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II). Circulation 1994 Mar; 89(3):1333-445.
• •The Lipid Research Clinics Investigators. The Lipid Research Clinics Coronary Primary Prevention Trial: Results of 6 Years of Post-Trial Follow-up. Arch Intern Med 1992; 152:1399-1410.
• •Behrman RE et al (eds): Nelson, Textbook of Pediatrics, ed 15. Philadelphia, PA, WB Saunders Company, 1996.
• •Takemoto CK et al (eds): Pediatric Dosage Handbook, ed 3. Cleveland/Akron, OH, Lexi-Comp, Inc., 1996-1997.

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