CHOLESTYRAMINE RESIN

(koe-less-tear'a-meen)

LoCHOLEST, Questran, Questran Light, Prevalite
Classifications: antilipemic; bile acid sequestrant;
Therapeutic: cholesterol-lowering agent; bile acid sequestrant
Pregnancy Category: C

Availability

4 g powder for suspension; 1 g tablet

Action

Anion-exchange resin used for its cholesterol-lowering effect. Adsorbs and combines with intestinal bile acids in exchange for chloride ions to form an insoluble, nonabsorbable complex that is excreted in the feces. As a result, bile salts are continually (but not entirely) prevented from reentry into the enterohepatic circulation, thus increasing fecal loss of bile acids. This leads to lowered serum total cholesterol by decreasing low-density lipoprotein (LDL) cholesterol.

Therapeutic Effect

The resin anion-exchange agent increases fecal loss of bile acids which leads to lowered serum total cholesterol by decreasing (LDL) cholesterol, and reducing bile acid deposit in dermal tissues (decreasing pruritus). Serum triglyceride levels may increase or remain unchanged.

Uses

As adjunct to diet therapy in management of patients with primary hypercholesterolemia (type IIa hyperlipidemia) with a significant risk of atherosclerotic heart disease and MI; for relief of pruritus secondary to partial biliary stasis.

Unlabeled Uses

To control diarrhea caused by excess bile acids in colon; for hyperoxaluria.

Contraindications

Complete biliary obstruction or biliary cirrhosis, cholelithiasis; GI obstruction; hypersensitivity to bile acid sequestrants; coagulopathy; pregnancy (category C), lactation. Safe use in children ≤6 y not established.

Cautious Use

Bleeding disorders; hemorrhoids; impaired GI function, decreased GI motility; peptic ulcer, malabsorption states (e.g., steatorrhea); phenylketonuria (Questran Light only); renal disease.

Route & Dosage

Hypercholesterolemia
Adult: PO 4 g b.i.d. to q.i.d. a.c. and h.s., may need up to 24 g/d
Child: PO 240 mg/kg/d in 3 divided doses

Hyperlipoproteinemia
Adult: PO 4–8 g b.i.d. to q.i.d. a.c. and h.s. (≤32 g/d)

Pruritus
Adult: PO 4 g b.i.d. to q.i.d. a.c. and h.s. (≤16 g/d)

Administration

Oral

Place contents of one packet or one level scoopful on surface of at least 120 to 180 mL (4–6 oz) of water or other preferred liquid. Permit drug to hydrate by standing without stirring 1–2 min, twirling glass occasionally, then stir until suspension is uniform. Rinse glass with small amount of liquid and have patient drink remainder to ensure entire dose is taken. Administer before meals.
Always dissolve cholestyramine powder before administration; it is irritating to mucous membranes and may cause esophageal impaction if administered dry.
Store in tightly closed container at 15°–30° C (59°–86° F) unless otherwise specified.

Adverse Effects (≥1%)

GI: Constipation, fecal impaction, hemorrhoids, abdominal pain and distension, flatulence, bloating sensation, belching, nausea, vomiting, heartburn, anorexia, diarrhea, steatorrhea. Endocrine: Increased libido. Metabolic: Weight loss or gain, iron, calcium, vitamin A, D, and K deficiencies (from poor absorption); hypoprothrombinemia, hyperchloremic acidosis, decreased erythrocyte folate levels. Skin: Rash, irritations of skin, tongue, and perianal areas. Special Senses: Arcus juvenilis, uveitis.

Diagnostic Test Interference

Cholestyramine therapy may be accompanied by increased serum AST, phosphorus, chloride, and alkaline phosphatase levels; decreased serum calcium, sodium, and potassium levels.

Interactions

Drug: Decreases the absorption of oral anticoagulants, digoxin, tetracyclines, penicillins, phenobarbital, thyroid hormones, thiazide diuretics, iron salts, fat-soluble vitamins (A, D, E, K) from the GI tract—administer cholestyramine 4 h before or 2 h after these drugs. Can bind to and affect absorption of any drug.

Pharmacokinetics

Absorption: Not absorbed from GI tract. Elimination: Excreted in feces as insoluble complex.

Nursing Implications

Assessment & Drug Effects

Monitor therapeutic effect. Serum cholesterol levels are reduced within 24–48 h after treatment starts and may continue to decline for a year. After withdrawal of cholestyramine, cholesterol levels usually return to baseline level in about 2 to 4 wk.
Be alert to early symptoms of hypoprothrombinemia (petechiae, ecchymoses, abnormal bleeding from mucous membranes, tarry stools) and report their occurrence promptly. Long-term use of cholestyramine resin can increase bleeding tendency.
Preexisting constipation may be worsened in the older adult, women, and in those taking >24 g/d.
Consult physician regarding supplemental vitamins A and D and folic acid that may be required by patient on long-term therapy.
Lab tests: Periodic CBC, platelet count, serum electrolytes, and lipid profile.

Patient & Family Education

Report constipation immediately to physician. High-bulk diet with adequate fluid intake is an essential adjunct to cholestyramine treatment and generally resolves the problems of constipation and bloating sensation.
Do not omit doses. Sudden withdrawal can promote uninhibited absorption of other drugs taken concomitantly, leading to toxicity or overdosage.
GI adverse effects usually subside after the first month of drug therapy.
The following symptoms may be drug-induced and should be reported promptly: severe gastric distress with nausea and vomiting, unusual weight loss, black stools, severe hemorrhoids (GI bleeding), sudden back pain.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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