Colestyramine/Questran

Colestyramine is one of the longest-established medicines for cholesterol lowering, with a track record of use in lipid management spanning several decades. Colestyramine powder, sold under brand names including Questran and Questran Light, is a prescription-only bile acid sequestrant used in adults for LDL reduction in hypercholesterolaemia, relief of pruritus in biliary obstruction, and management of certain types of diarrhoea. The product stocked at Pharmacy Planet is Colestyramine Light 4g powder for oral suspension by Mylan, an aspartame-sweetened formulation supplied as sachets. A prescription can only be issued following a clinical consultation.

Colestyramine is an oral prescription medicine and a bile acid sequestrant (anion exchange resin). The Colestyramine Light 4g formulation by Mylan is sweetened with aspartame rather than sucrose, making it relevant for patients who need to limit sugar intake. Questran and Questran Light are well-known brand names for colestyramine from another manufacturer; the active ingredient and mechanism are identical across all colestyramine formulations regardless of brand or manufacturer.

Colestyramine is licensed in the UK for three clinical indications. The primary indication is as adjunctive therapy to diet for the reduction of elevated serum cholesterol in patients with primary hypercholesterolaemia who do not respond adequately to diet alone. The second indication is relief of pruritus (itching) associated with partial biliary obstruction, including primary biliary cirrhosis, and other causes of bile acid deposits in the skin. The third indication is treatment of radiation induced diarrhoea and diarrhoea associated with ileal disease, vagotomy, and diabetic vagal neuropathy.

Each sachet of Colestyramine Light contains 4g of colestyramine (anhydrous). The sachets are mixed with water or another suitable liquid before swallowing. Colestyramine is not absorbed into the body and works entirely within the digestive system.

Bile Acid Sequestration and LDL Reduction. The liver converts cholesterol into bile acids, which are secreted into the small intestine for fat digestion and normally recycled back to the liver through enterohepatic circulation. Colestyramine is a large positively charged resin that binds to bile acids in the gut, forming insoluble complexes excreted in the faeces. The liver then increases its conversion of cholesterol into new bile acids, causing liver cells to upregulate LDL receptors, which capture more LDL cholesterol from the bloodstream.

Relief of Pruritus in Biliary Obstruction. In patients with partial biliary obstruction, bile acids accumulate in the skin and cause pruritus. By binding bile acids in the gut and reducing the total body pool of bile acids, colestyramine can relieve this itching — a separate mechanism from cholesterol lowering.

Diarrhoea Management. In bile acid malabsorption diarrhoea (following ileal resection, vagotomy, radiation, or diabetic vagal neuropathy), excess bile acids enter the colon and stimulate fluid secretion. Colestyramine binds these excess bile acids, reducing their diarrhoea-inducing effect.

Always take colestyramine exactly as your prescriber instructs. Read the Patient Information Leaflet supplied with your medicine before starting treatment.

• Never take colestyramine dry. Always mix the powder with liquid before swallowing.
• Mix the contents of one sachet with at least 150ml of water, fruit juice, skimmed milk, thin soups, or pulpy fruits with high moisture content. Stir until completely mixed and drink straight away.
• Rinse the glass with a little extra liquid and drink that too.
• Take colestyramine immediately before, during, or shortly after meals.
• All other oral medicines must be taken at least one hour before or four to six hours after colestyramine.

If you miss a dose, take it as soon as you remember with your next meal. If you only remember between meals, skip the missed dose and take the next scheduled dose with your following meal. Do not take two doses at once. Do not stop taking colestyramine without speaking to your prescriber first.

Your prescriber will arrange blood tests to monitor your lipid levels before and after starting treatment.

Each sachet contains 4g of colestyramine. For hypercholesterolaemia, the SmPC recommends a starting dose of one sachet (4g) once or twice daily, mixed with liquid with meals. The dose may be increased gradually, typically to two to four sachets per day in divided doses with meals, based on lipid response and tolerability. The maximum recommended daily dose for cholesterol lowering is generally considered to be 24g per day, though most patients are treated at doses of 8g to 16g per day. Higher doses increase gastrointestinal side effects significantly.

For pruritus and diarrhoea indications, the dose and schedule differ from the cholesterol lowering indication. Your prescriber will advise on the appropriate dose for your specific clinical situation. Colestyramine Light 4g sachets are sweetened with aspartame (a source of phenylalanine) rather than sucrose. Patients with phenylketonuria must not use this formulation.

The side effects of colestyramine are predominantly gastrointestinal. Because it is not absorbed into the body, it does not cause systemic side effects.

Common Side Effects (may affect up to 1 in 10 people):

• Constipation — the most commonly reported side effect and the most frequent reason for stopping treatment. Starting at one sachet per day and increasing gradually helps. Adequate fluid intake and dietary fibre are strongly recommended.
• Nausea, vomiting, and abdominal discomfort.
• Flatulence and bloating.

Uncommon Side Effects (may affect up to 1 in 100 people):

• Raised triglyceride levels, monitored during treatment.
• Perianal irritation or haemorrhoids, often related to constipation.
• Dental erosion with prolonged use — using water rather than acidic juices when mixing can reduce this risk.

Long-Term Use: Vitamin Deficiency Risk. Colestyramine can impair absorption of fat-soluble vitamins (A, D, E, K) and folic acid during prolonged treatment. Vitamin K deficiency can cause increased bleeding/bruising; vitamin D deficiency can contribute to bone thinning. Supplements should be taken at least one hour before or four to six hours after colestyramine.

Serious Side Effects — Seek Urgent Medical Attention: Go to your nearest accident and emergency department or call 999 immediately if you experience choking or difficulty swallowing after taking the powder; signs of bowel obstruction such as severe abdominal pain, inability to pass stools, and vomiting; signs of vitamin K deficiency such as unusual bruising or bleeding; or signs of a severe allergic reaction such as sudden widespread rash, difficulty breathing, or swelling of the face, lips, tongue, or throat.

Colestyramine may be suitable if you:

• Are an adult with primary hypercholesterolaemia where LDL reduction is required and dietary measures have been insufficient.
• Require a statin alternative for cholesterol management when a statin is not appropriate or not tolerated.
• Need additional LDL reduction alongside a statin or other lipid lowering treatment.
• Have pruritus associated with partial biliary obstruction or primary biliary cirrhosis and your prescriber has recommended colestyramine.
• Have bile acid malabsorption diarrhoea from ileal disease, radiation, vagotomy, or diabetic vagal neuropathy.
• Are able to mix the powder with liquid and swallow it reliably at each dose.
• Are already prescribed colestyramine and require a repeat prescription through an online prescribing service.

Colestyramine is not suitable if you:

• Have complete biliary obstruction.
• Have phenylketonuria, as Colestyramine Light contains aspartame.
• Have severely elevated triglyceride levels.
• Have dysphagia.
• Are pregnant or planning to become pregnant.
• Are breastfeeding.
• Are under 18 years of age (for the cholesterol indication).
• Have a known allergy or hypersensitivity to colestyramine or any excipient listed in the SmPC.

Important Drug Interactions — Timing Is Critical: Colestyramine has one of the most extensive drug interaction profiles of any medicine in this category, as it can bind to and reduce the absorption of a very wide range of oral medicines including statins, levothyroxine, warfarin, digoxin, thiazide diuretics, furosemide, propranolol and other beta blockers, fat-soluble vitamins and folic acid, oral contraceptives, paracetamol, phenobarbitone, and aspirin. All other oral medicines must be taken at least one hour before or four to six hours after colestyramine.

Colestyramine is a Prescription Only Medicine. The clinical consultation is the essential first step. A prescription will only be issued if a registered prescriber concludes, based on their individual assessment of your circumstances, that colestyramine is clinically appropriate for you.

During your online consultation with Pharmacy Planet, a registered prescriber will review your cholesterol or lipid levels, the indication being treated, current medicines, phenylketonuria status, and other relevant medical history. The prescriber will confirm that colestyramine is appropriate for your needs and determine whether online prescribing is suitable for your situation.

Not all consultations will result in a prescription. The prescriber may request blood test results, recommend a different approach to lipid or symptom management, or advise that a more detailed review by your GP is needed.