Olestar

Approved Indications:

• Primary Hypercholesterolemia (Type IIa): Adjunct to diet for the reduction of elevated serum cholesterol, particularly LDL cholesterol.
• Pruritus Associated with Partial Biliary Obstruction: Used to relieve itching due to bile acid accumulation.
• Cholestatic Liver Disease–Related Pruritus: Particularly effective in intrahepatic cholestasis or primary biliary cholangitis.
• Digitalis Toxicity: Useful as adjunctive therapy to prevent reabsorption of digitoxin.
• Diarrhea due to Bile Acid Malabsorption: Especially in cases of ileal resection, Crohn’s disease, or post-cholecystectomy.

Clinically Accepted Off-Label Uses:

• Irritable Bowel Syndrome with Diarrhea (IBS-D): Used to reduce bile acid–induced symptoms.
• Clostridioides difficile–Associated Diarrhea (Adjunct): In some protocols, used to bind toxins and reduce recurrence.
• Microscopic Colitis: Has been used successfully in controlling chronic watery diarrhea.

Available Forms: Powder for oral suspension (typically 4 g per packet or scoop; containing 4 g of cholestyramine resin equivalent to 9 g total formulation including excipients)

Adults:

• Hypercholesterolemia:
• Initial: 4 g orally once or twice daily
• Maintenance: 8–16 g/day divided in 2 doses
• Max: 24 g/day (divided doses)
• Bile Acid Sequestration (Diarrhea or Pruritus):
• 4 g once or twice daily; titrate up to 16 g/day if necessary

Pediatrics (≥6 years):

• Hypercholesterolemia or Diarrhea:
• 240 mg/kg/day in divided doses; adjust based on response and tolerance
• Usual range: 2–8 g/day

Elderly:

• Same as adults; monitor for GI side effects and nutrient malabsorption

Renal Impairment: No dose adjustment required

Hepatic Impairment: No dose adjustment needed; caution in patients with obstructive jaundice or hepatic dysfunction

Administration:

• Must be mixed with at least 60–180 mL of water, juice, soup, or non-carbonated beverage before ingestion
• Administer other medications at least 1 hour before or 4–6 hours after cholestyramine to avoid drug binding
• Can be taken with meals or before bedtime

Cholestyramine resin is a non-absorbable, anion-exchange resin that binds bile acids in the intestine to form an insoluble complex, preventing their reabsorption in the terminal ileum. This interrupting of the enterohepatic circulation leads to increased conversion of cholesterol into bile acids in the liver, which reduces intrahepatic cholesterol levels and upregulates LDL receptor expression. Consequently, LDL cholesterol is cleared from the bloodstream. In conditions like bile acid diarrhea or pruritus, binding of bile acids prevents mucosal irritation and systemic deposition, respectively.

Cholestyramine is not systemically absorbed; its actions are confined to the gastrointestinal tract.

• Absorption: None; remains within GI lumen
• Distribution: Not applicable
• Metabolism: Not metabolized
• Excretion: Eliminated in feces as resin-bile acid complex
• Onset of action:
• Lipid-lowering: 1–2 weeks
• Pruritus/diarrhea relief: Within days to a week
• Duration: Effects persist while treatment continues; reversed upon discontinuation

• Pregnancy: Classified as FDA Pregnancy Category C (older system). No controlled human studies, but widely used during pregnancy when benefits outweigh risks. May interfere with absorption of fat-soluble vitamins (A, D, E, K) important during pregnancy.
• Lactation: Not systemically absorbed; considered compatible with breastfeeding. However, may reduce maternal vitamin absorption and subsequently affect breast milk nutrient content. Supplementation may be needed.
• Caution: Monitor fat-soluble vitamin levels in both mother and infant during prolonged use.

• Primary Class: Bile Acid Sequestrant / Antihyperlipidemic Agent
• Subclass: Non-systemic anion-exchange resin

• Complete biliary obstruction
• Hypersensitivity to cholestyramine or any formulation components
• Phenylketonuria (if flavored formulations contain aspartame)
• GI motility disorders (e.g., severe constipation, bowel obstruction)

• Fat-soluble vitamin deficiency: Long-term use can cause deficiencies in vitamins A, D, E, and K—especially in children and malnourished patients.
• Phenylketonuria risk: Some formulations contain phenylalanine.
• Constipation: Common, especially in elderly and pediatric patients; may lead to fecal impaction.
• Drug interactions: Binds many medications; spacing doses is critical.
• Monitoring: Periodic lipid panel, liver function tests, and fat-soluble vitamin levels if used long-term.

Gastrointestinal (most common):

• Constipation (dose-dependent)
• Bloating, flatulence
• Abdominal discomfort
• Nausea or vomiting
• Fecal impaction (especially in elderly)

Metabolic/Nutritional:

• Hypoprothrombinemia (due to vitamin K deficiency)
• Steatorrhea or fat malabsorption (rare with high doses)
• Vitamin A, D, E, or K deficiency symptoms (long-term use)

Rare and Serious:

• GI obstruction
• Hyperchloremic metabolic acidosis (especially in children with renal impairment)
• Allergic reactions (rash, urticaria)

Onset: Typically within days to weeks of therapy, severity is dose-related.

Major Interactions:

• Binding interactions: Decreases absorption of several drugs:
• Warfarin
• Digoxin
• Thiazide diuretics
• Propranolol
• Levothyroxine
• Oral contraceptives
• Fat-soluble vitamins (A, D, E, K)

Mechanism: Physical binding within GI lumen leads to decreased bioavailability

Enzyme Systems: Not metabolized by or affecting CYP450 enzymes

Management:

• Administer other drugs 1 hour before or 4–6 hours after cholestyramine

Food interactions: None significant; may be taken with food to improve palatability.

Alcohol: No known direct interaction.

• 2023 ACC/AHA Guidelines on Lipid Management: Bile acid sequestrants including cholestyramine may be used as second-line agents when statins are not tolerated or LDL targets are not met.
• 2024 EMA review: Emphasized safety in long-term use but recommended regular vitamin level monitoring.
• Use in pediatric familial hypercholesterolemia reaffirmed when statins are contraindicated or as add-on therapy.

• Temperature: Store below 25°C (room temperature)
• Humidity: Keep container tightly closed to protect from moisture
• Light Protection: No special requirement; store away from direct sunlight
• Handling Precautions:
• Use dry spoon for dispensing
• Do not store prepared suspension; prepare fresh before each dose
• Reconstitution: Mix powder with water, juice, or other non-carbonated beverages before use
• Shelf life: Follow manufacturer’s expiration date; do not use expired sachets or open containers beyond stability period