Reviewed on 5/24/2022

What Is Colesevelam and How Does It Work?

Colesevelam is a prescription medication used to treat hyperlipidemia and to improve glycemic control in adults with type 2 diabetes mellitus

  • Colesevelam is available under the following different brand names: WelChol 

What Are Dosages of Colesevelam?

Adult and pediatric dosage


  • 625mg

Powder for oral suspension

  • 3.75g/packet


Adult dosage

  • Tablet: 1.875 g (3 tablets) orally every 12 hours or 3.75 g (6 tablets) orally once a day
  • Oral suspension: 1.875 g (½ packet) orally every 12 hours or 3.75 g (1 packet) orally once a day

Type 2 Diabetes Mellitus

Adult dosage

  • Tablet: 1.875 g (3 tablets) orally every 12 hours or 3.75 g (6 tablets) orally once a day
  • Oral suspension: 1.875 g (½ packet) orally every12hr or 3.75 g (1 packet) orally once a day

Heterozygous Familial Hypercholesterolemia

Pediatric dosage

  • Children below 10 years: Safety and efficacy not established
  • Children between 10-17 years
  • Tablet: 1.875 g (3 tablets) orally every 12 hours or 3.75 g (6 tablets) orally once a day
  • Oral suspension: 1.875 g (½ packet) orally every12hour or 3.75 g (1 packet) orally once a day
  • Due to tablet size, the oral suspension is recommended for use in the pediatric population

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Are Side Effects Associated with Using Colesevelam?

Common side effects of Colesevelam include:

  • constipation,
  • upset stomach,
  • nausea,
  • vomiting,
  • gas,
  • indigestion,
  • feeling weak or tired,
  • headache,
  • muscle pain,
  • runny nose,
  • sore throat, or
  • flu symptoms.

Serious side effects of Colesevelam include:

  • trouble swallowing, or
  • unusual bleeding or bruising.

Rare side effects of Colesevelam include:

  • none 

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Colesevelam?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Colesevelam has severe interactions with no other drugs.
  • Colesevelam has serious interactions with no other drugs
  • Colesevelam has moderate interactions with at least 23 other drugs.
  • Colesevelam has minor interactions with the following drugs:

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Colesevelam?


  • Serum TG concentrations above 500 mg/dL
  • History of hypertriglyceridemia-induced pancreatitis
  • History of bowel obstruction

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Colesevelam?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Colesevelam?”


  • Tablets can cause dysphagia or esophageal obstruction due to size; for patients with difficulty swallowing tablets use the oral suspension
  • May increase serum TG concentrations, hypertriglyceridemia can cause acute pancreatitis
  • Secondary causes of hyperlipidemia must be ruled out before therapy is initiated
  • Postmarketing cases of bowel obstruction have occurred; not recommended in gastroparesis (constipating effects); instruct patients to promptly discontinue therapy and seek medical attention if severe abdominal pain or severe constipation occurs
  • May exacerbate pre-existing constipation (initiate therapy at a lower dosage in patients with a history of constipation)
  • Seek prompt medical attention if symptoms of acute pancreatitis occur (e.g., severe abdominal pain with or without nausea and vomiting)
  • Phenylalanine can be harmful to patients with phenylketonuria (PKU); before prescribing oral suspension to a patient with PKU, consider a combined daily amount of phenylalanine from all sources, including oral suspension
  • Drug interactions overview
    • May reduce the absorption of some drugs and nutrients; administer drugs with known interactions or narrow therapeutic index 4 hours before colesevelam
    • Bile acid sequestrants may decrease absorption of fat-soluble vitamins; administer vitamin at least 4 hr before colesevelam
    • In vivo drug interactions studies showed a decrease in exposure of Ethinyl estradiol, norethindrone, olmesartan, and sulfonylureas when coadministered with colesevelam; also showed an increase in metformin ER when coadministered with colesevelam
    • Adverse reactions resulting from coadministration with colesevelam
      • Increased seizure activity or decreased phenytoin levels in patients receiving phenytoin
      • Reduced INR in patients receiving warfarin therapy; monitor INR
      • Elevated thyroid-stimulating hormone (TSH) in patients receiving thyroid hormone replacement therapy; administer thyroid hormone replacement therapy 4 hours before colesevelam

Pregnancy And Lactation

  • There are no adequate and well-controlled studies of colesevelam hydrochloride use in pregnant women
  • In the postmarketing setting, there have been reports of pregnancy and a causal association with congenital anomalies has not been established
  • Contraception
    • Coadministration with colesevelam and oral contraceptives may reduce the efficacy of oral contraceptives; advise patients to take oral contraceptives at least 4 hours before taking therapy
  • Lactation
    • Not absorbed systemically by the mother following oral administration, and breastfeeding is not expected to result in the exposure of the child to drug

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