Questran Light - Drug Monograph

Introduction

Questran Light (cholestyramine light) is a bile acid sequestrant medication used primarily for the management of hypercholesterolemia and pruritus associated with partial biliary obstruction. It is a modified formulation of the original Questran, offering improved palatability with reduced sugar content while maintaining therapeutic efficacy.

Mechanism of Action

Questran Light binds bile acids in the intestinal lumen, forming an insoluble complex that is excreted in feces. This process interrupts the enterohepatic circulation of bile acids, leading to increased hepatic conversion of cholesterol into bile acids. The resulting depletion of hepatic cholesterol increases hepatic LDL receptor activity and clearance of LDL cholesterol from plasma. Additionally, by binding bile acids in the intestine, it reduces the concentration of bile acids that contribute to pruritus in cholestatic liver diseases.

Indications

• Primary hyperlipidemia: As adjunctive therapy to diet and other lipid-lowering agents
• Pruritus associated with partial biliary obstruction
• Off-label uses: Diarrhea due to bile acid malabsorption, Clostridium difficile colitis

Dosage and Administration

• Mix with 2-6 ounces of water, milk, fruit juice, or other non-carbonated beverage
• Stir thoroughly and drink immediately
• Take other medications at least 1 hour before or 4-6 hours after Questran Light
• Dosage titration should occur at 4-week intervals

• Pediatric: Safety and efficacy not established
• Geriatric: No specific dosage adjustment required
• Renal/hepatic impairment: No dosage adjustment recommended

Pharmacokinetics

Contraindications

• Complete biliary obstruction (no bile acid secretion into intestine)
• Hypersensitivity to cholestyramine or any component
• Bowel obstruction
• Phenylketonuria (contains aspartame)

Warnings and Precautions

• May cause constipation, which could lead to fecal impaction
• May reduce absorption of fat-soluble vitamins (A, D, E, K) with long-term use
• Use caution in patients with gastrointestinal disorders
• May increase triglycerides in hypertriglyceridemic patients
• Phenylketonuria: Contains phenylalanine (16.8 mg per dose)

Drug Interactions

• Warfarin: Reduced absorption and anticoagulant effect
• Thiazide diuretics: Reduced absorption
• Digitalis glycosides: Reduced absorption and efficacy
• Thyroid preparations: Reduced absorption
• Propranolol: Reduced absorption
• Fat-soluble vitamins: Reduced absorption
• Oral contraceptives: Potential reduced efficacy

Adverse Effects

• Constipation (most common)
• Abdominal discomfort
• Flatulence
• Nausea
• Heartburn

• Diarrhea
• Dyspepsia
• Steatorrhea
• Anorexia

• Fecal impaction
• Gallstone formation
• Intestinal obstruction
• Hyperchloremic acidosis
• Vitamin deficiencies (with long-term use)

Monitoring Parameters

• Baseline and periodic lipid profiles (every 4-8 weeks initially)
• Liver function tests
• Coagulation parameters (if on anticoagulants)
• Serum electrolytes with long-term use
• Bowel function and stool characteristics
• Vitamin levels with prolonged therapy
• Triglyceride levels (may increase)

Patient Education

• Take medication as directed, typically before meals
• Mix thoroughly with liquid and drink immediately
• Maintain adequate fluid intake to prevent constipation
• Report severe constipation, abdominal pain, or rectal bleeding
• Separate other medications by at least 1 hour before or 4-6 hours after Questran Light
• Maintain recommended dietary modifications
• Inform all healthcare providers about Questran Light use
• Report any signs of vitamin deficiency (bruising, bleeding, vision changes)
• Not for use during pregnancy without medical supervision

References

1. FDA prescribing information: Questran Light (cholestyramine) 2. Grundy SM, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol. J Am Coll Cardiol. 2019;73(24):e285-e350. 3. Insull W. Clinical utility of bile acid sequestrants in the treatment of dyslipidemia: a scientific review. South Med J. 2006;99(3):257-273. 4. American College of Gastroenterology guidelines on the management of hyperlipidemia 5. UpToDate: Cholestyramine drug information 6. Micromedex: Cholestyramine therapeutic monograph 7. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-.