Pharmacology · Bile acid sequestrants
Colesevelam !
A bile acid sequestrant that lowers LDL and also modestly lowers glucose in type 2 diabetes. Fewer drug-binding problems than colestyramine.
Updated 2026-11-01
Mechanism of action
Colesevelam is a non-absorbed polymer with a high affinity for bile acids. It holds them in the gut so they are lost in the stool; the liver uses more cholesterol to make new bile acids and raises its LDL receptors, which lowers LDL. It also lowers HbA1c in type 2 diabetes, by mechanisms not fully understood.
- Polymer binds bile acids in the gut
- Bile acids are lost in the stool
- Liver converts cholesterol to bile acids and adds LDL receptors
- LDL falls; HbA1c falls modestly in type 2 diabetes
Pharmacokinetics
- Absorption
- Not absorbed systemically.
- Elimination
- In the stool.
Indications
- Primary hyperlipidemia (high LDL), alone or with a statin Atherosclerosis and dyslipidaemia →
- Heterozygous familial hypercholesterolemia in children and adolescents Familial hypercholesterolemia →
- Type 2 diabetes, to improve glucose control as an adjunct Type 2 diabetes mellitus →
Adverse effects
Common
- Constipation
- Dyspepsia, nausea
- Rise in triglycerides
Contraindications
- Very high serum triglycerides
- History of pancreatitis caused by hypertriglyceridemia
- History of bowel obstruction
Key interactions
- Levothyroxine, oral contraceptives, glyburide and other sulfonylureas, phenytoin, cyclosporine, warfarin
- Exposure may fall; these drugs are taken at least 4 hours before colesevelam and levels or effects are watched.
- Metformin extended-release
- Exposure rises; glucose response is monitored.
- Fat-soluble vitamins
- May reduce absorption of vitamins A, D, E and K; supplements are taken at least 4 hours before.
What is monitored
- Lipid panel including triglycerides before and during treatment
- HbA1c and glucose in diabetes
- Bowel habits and swallowing
Administration and safety
- Tablets are large: taken with a meal and plenty of liquid; the oral suspension is used if swallowing is difficult.
- Interacting drugs (for example levothyroxine and oral contraceptives) are taken at least 4 hours before.
- Avoided in gastroparesis, other motility disorders and after major gut surgery.
Nursing care
- Before: lipid panel with triglycerides, bowel and swallowing history, full medication list.
- Teach to report severe stomach pain (pancreatitis) or severe constipation.
- Watch glucose in patients on antidiabetic drugs.
- Plan medication timing to keep the 4-hour gap.
Pregnancy and breastfeeding
Not absorbed systemically, so fetal exposure is not expected; it may reduce absorption of fat-soluble vitamins.
Test yourself
Think of the answer, then tap the question to see it.
Which additional indication does colesevelam have besides LDL lowering?
Improving glucose control in type 2 diabetes, as an adjunct.
Which triglyceride situation contraindicates colesevelam?
Very high triglycerides or a history of pancreatitis caused by hypertriglyceridemia.
A patient takes levothyroxine and starts colesevelam. What timing applies?
Levothyroxine is taken at least 4 hours before colesevelam, and thyroid tests are monitored.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Colesevelam: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); DailyMed - COLESEVELAM HYDROCHLORIDE tablet (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.