When this section is removed, the bile acids pass into the large bowel and cause diarrhea due to stimulation of chloride/fluid secretion by the colonocytes resulting in a secretory diarrhea. Colestyramine prevents this increase in water by making the bile acids insoluble and osmotically inactive. Colestyramine is also used in the control of other types of bile acid diarrhea. The primary, idiopathic form of bile acid diarrhea is a common cause of chronic functional diarrhea, often misdiagnosed as diarrhea-predominant irritable bowel syndrome (IBS-D), and most of these patients respond to colestyramine. It is beneficial in the treatment of postcholecystectomy syndrome chronic diarrhea. Colestyramine is also useful in treating post-vagotomy diarrhea.Colestyramine can be helpful in the treatment of Clostridium difficile infections, to absorb toxins A and B, and reduce the diarrhea and the other symptoms these toxins cause. However, because it is not an anti-infective, it is used in concert with vancomycin.It is also used in the "wash out" procedure in patients taking leflunomide or teriflunomide to aid drug elimination in the case of drug discontinuation due to severe side effects caused by leflunomide or teriflunomide.A case report suggests that colestyramine may be useful for cyanobacterial (microcystin) poisoning in dogs.Ointments containing colestyramine compounded with aquaphor have been used in topical treatment of diaper rash in infants and toddlers.Cholestyramine also binds with oxalate in the GI tract, ultimately reducing urine oxalate and calcium oxalate stone formation. Available forms
Colestyramine is available as powder form, in 4-g packets, or in larger canisters.
In the United States, it can be purchased either as a generic medicine, or as Questran or Questran Light (Bristol-Myers Squibb). Dosage
A typical dose is 4 to 8 g once or twice daily, with a maximum dose of 24 g/d. Side effects
These side effects have been noted:
Most frequent: constipation
Increased plasma triglyceridesIntestinal obstruction has been reported in patients with previous bowel surgery who should use colestyramine cautiously. Cholestyramine-induced hyperchloremic metabolic acidosis has also been reported rarely.Patients with hypothyroidism, diabetes, nephrotic syndrome, dysproteinemia, obstructive liver disease, kidney disease, or alcoholism should consult their doctor before taking this medication. Other drugs should be taken at least one hour before or four to six hours after colestyramine to reduce possible interference with absorption. Patients with phenylketonuria should consult with a physician before taking Questran Light because that product contains phenylalanine. Drug interactions
Interactions with these drugs have been noted:
Digitalis
Estrogens and progestins
Oral diabetes drugs
Penicillin G
Phenobarbital
Spironolactone
Tetracycline
Thiazide-type diuretic pills
Thyroid medication
Warfarin
LeflunomideMost interactions are due to the risk of decreased absorption of these drugs. The duration of treatment is not limited, but the prescribing physician should reassess at regular intervals if continued treatment is still necessary. The principal overdose risk is blockage of intestine or stomach. Colestyramine may interfere in the absorption of fat-soluble vitamins such as vitamins A, D, E, and K. No special considerations regarding alcohol consumption are made. Notes and references
The Merck Index (12 ed.). p. 2257. External links
U.S. National Library of Medicine: Drug Information Portal - Cholestyramine