Medications and Drugs

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Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD

GENERIC NAME: colestipol

BRAND NAME: Colestid

DRUG CLASS AND MECHANISM: Colestipol is an oral cholesterol-lowering drug that is not absorbed from the intestine into the body. Rather, it works by binding to bile acids in the intestine and promoting the elimination of bile acids in the stool. Bile acids are formed in the liver from cholesterol, secreted into bile and with the bile enter the intestine. Most of the bile acids are reabsorbed from the intestine back into the body to be cycled again through the liver and bile. By promoting the elimination of bile acids, colestipol forces the liver to convert more cholesterol into bile acids in order to replace the lost bile acids. This reduces the levels of cholesterol within the body. Colestipol works similarly to cholestyramine (Questran). Colestipol was approved by the FDA in 1977.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Granules: 5 gm/ packet or bulk (5gm/teaspoonful) in canisters. Tablets: 1 gm.

STORAGE: Tablets and granules should be stored at room temperature, 20 to 25 C (68  to 77 F).

PRESCRIBED FOR: Colestipol is used together with dietary modifications for the treatment of high blood cholesterol levels. Other less common uses include treatment of diarrhea due to increased intestinal bile acids after some types of intestinal surgery and treatment of itching associated with partial obstruction to the flow of bile due to liver disease. The itching is believed to be due to the accumulation of bile acids in the body.

DOSING: Colestipol is most often prescribed in 2 to 4 divided doses but may also be prescribed once daily. The usual adult dose is 2-16 gm of tablets administered once or twice daily or 5-30 grams of granules once daily or 4 times daily.

Tablets should not be cut, crushed or chewed. Granules should be mixed in three ounces of fluid (water or fruit juice).

DRUG INTERACTIONS: Colestipol binds many different compounds in the gastrointestinal tract, thereby inhibiting their absorption into the body. For example, colestipol can bind with and decrease the oral absorption of carbamazepine (Tegretol), diuretics such as hydrochlorothiazide (found in Dyazide, Maxzide) and furosemide (Lasix), propranolol (Inderal), tetracyclines, and fat-soluble vitamins (vitamins A, D, and K). Colestipol can bind with and inhibit the absorption of thyroid hormones. Colestipol also can bind with ursodiol (Actigall, Urso).

Separating the doses of colestipol and these other compounds by several hours should prevent binding with colestipol. Generally, other drugs should be administered one hour before colestipol or 4 hours after colestipol is administered.

Colestipol binds to vitamin K, a vitamin which is required by the liver to make the factors that allow blood to clot. Colestipol, by reducing the action of vitamin K, may exaggerate the effect of warfarin (Coumadin), reducing the body's ability to form blood clots. This interaction could lead to abnormal bleeding. On the other hand, colestipol can bind with warfarin directly and inhibit the absorption of warfarin. To avoid this interaction, doses of warfarin and colestipol should be separated by at least 4-6 hours.

Colestipol is closely related to cholestyramine. Cholestyramine has been more extensively studied than colestipol. Therefore, there are several drug interactions which have been described with cholestyramine for which data is lacking with colestipol. It would be prudent to assume that a similar interactions exist for both drugs and to separate ingestion of colestipol from the other drugs by several hours. These interactions with cholestyramine include: acetaminophen (Tylenol), amiodarone (Cordarone), gemfibrozil (Lopid), pravastatin (Pravachol), piroxicam (Feldene), imipramine (Tofranil), glipizide (Glucotrol), and others.