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Welchol Side Effects

Generic name: colesevelam

Medically reviewed by Last updated on May 2, 2023.

Note: This document contains side effect information about colesevelam. Some dosage forms listed on this page may not apply to the brand name Welchol.


Common side effects of Welchol include: constipation. Other side effects include: dyspepsia. Continue reading for a comprehensive list of adverse effects.

Applies to colesevelam: oral powder for suspension, oral tablet.

Serious side effects of Welchol

Along with its needed effects, colesevelam (the active ingredient contained in Welchol) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking colesevelam:

More common

Less common

  • Anxiety
  • blurred vision
  • body aches or pain
  • chills
  • cold sweats
  • confusion
  • cool, pale skin
  • cough
  • depression
  • diarrhea
  • difficulty in breathing
  • difficulty in moving
  • dizziness
  • dry or sore throat
  • ear congestion
  • general feeling of discomfort or illness
  • hoarseness
  • increased hunger
  • joint pain or swelling
  • loss of appetite
  • loss of consciousness
  • loss of voice
  • muscle pains, cramps, or stiffness
  • nausea
  • nervousness
  • nightmares
  • pounding in the ears
  • seizures
  • shakiness
  • shivering
  • slow or fast heartbeat
  • slurred speech
  • sneezing
  • stuffy or runny nose
  • sweating
  • tender, swollen glands in the neck
  • trouble with sleeping
  • trouble with swallowing
  • voice changes
  • vomiting

Incidence not known

  • Bleeding after defecation
  • dark urine
  • pain or discomfort in the chest
  • pains in the stomach, side, or abdomen, possibly radiating to the back
  • swelling of the stomach area
  • unable to swallow saliva
  • uncomfortable swelling around the anus
  • yellow eyes or skin

Other side effects of Welchol

Some side effects of colesevelam may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

  • Accidental injury
  • back pain
  • lack or loss of strength

For Healthcare Professionals

Applies to colesevelam: oral powder for reconstitution, oral tablet.


The most frequently reported side effects were constipation, dyspepsia, and nausea.[Ref]


Very common (10% or more): Constipation (up to 11%), flatulence

Common (1% to 10%): Dyspepsia, nausea, vomiting, diarrhea, abdominal pain, abnormal stools, abdominal distension

Uncommon (0.1% to 1%): Dysphagia

Very rare (less than 0.01%): Pancreatitis

Frequency not reported: Intestinal obstruction

Postmarketing reports: Bowel obstruction, esophageal obstruction, fecal impaction, exacerbation of hemorrhoids, pancreatitis[Ref]


Common (1% to 10%): Hypertriglyceridemia, hypoglycemia[Ref]


Common (1% to 10%): Hypertension, myocardial infarction, aortic stenosis, bradycardia[Ref]


Common (1% to 10%): Pharyngitis, rhinitis, nasopharyngitis, upper respiratory tract infection[Ref]


Common (1% to 10%): Accidental injury, asthenia, flu syndrome/influenza, fatigue, creatine phosphokinase increased

Uncommon (0.1% to 1%): Serum transaminases increased[Ref]


Common (1% to 10%): Myalgia, back pain[Ref]

Nervous system

Common (1% to 10%): Headache

Postmarketing reports: Increased seizure activity (resulting from decreased phenytoin levels)[Ref]


Frequency not reported: Hypersensitivity reaction[Ref]

In clinical trials of type 2 diabetes, patient who received this drug as an add on to a sulfonylurea discontinued the trial due to body rash and mouth blistering that occurred on the first day of therapy.[Ref]


Postmarketing reports: Reduced international normalized ration (INR) in patient on warfarin therapy


Postmarketing reports: Increased transaminases


Postmarketing reports: Elevated thyroid-stimulating hormone (TSH) in patients receiving thyroid hormone replacement


1. "Product Information. Welchol (colesevelam)." Daiichi Sankyo, Inc. (2001):

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.