colesevelam, Welchol

GENERIC NAME: colesevelam


DRUG CLASS AND MECHANISM: Colesevelam is an oral drug that lowers cholesterol levels in the blood. It also improves control of blood sugar in type 2 diabetes.

Cholesterol made by the liver or from the food we eat can be converted into bile acids by the liver. The bile acids are secreted by the liver into the bile and enter the intestine with the bile. In the intestine the bile acids assist with the digestion of fat. Some of the bile acids are excreted from the body with the stool, but the majority of bile acids are absorbed from the intestine into the blood, are removed by the liver from the blood, and are re-secreted into the bile. Colesevelam binds bile acids in the intestine and causes more of the bile acids to be excreted in the stool. This reduces the amount of bile acids that returns to the liver and forces the liver to make more bile acids to replace the bile acids lost in the stool. In order to make more bile acids, the liver converts more cholesterol into bile acids, and this lowers the level of cholesterol in the blood. Colesevelam is not absorbed into the body.

The mechanism whereby colesevelam improves blood sugar levels in people with diabetes is unknown.



PREPARATIONS: Tablet: 625 mg, white.

STORAGE: Colesevelam should be stored at room temperature, away from heat and light, and out of the reach of children.

PRESCRIBED FOR: Colesevelam is used to treat high blood cholesterol levels, especially high levels of LDL-cholesterol ("bad cholesterol"). It does not lower cholesterol as much as the statin class of drugs, but when used in combination with a statin, it lowers cholesterol levels further than the statin alone. Colesevelam is used in combination with other drugs for treating type 2 diabetes such as metformin, sulfonylureas, or insulin to further lower blood sugar levels.

DOSING: Colesevelam usually is taken one or two times daily with a meal.

DRUG INTERACTIONS: Colesevelam reduces the absorption of cyclosporine, glyburide (Micronase, DiaBeta, Glynase, Prestab), levothyroxine sodium (Synthroid, Levoxyl, Levothroid, Unithroid), and oral contraceptives containing ethinyl estradiol or norethindrone by binding to them in the stomach and preventing their absorption into the body. Colesevelam also may reduce the activity of phenytoin (Dilantin) and warfarin (Coumadin). Drugs that interact with colesevelam should be administered four hours before the administration of colesevelam and, when possible, drug levels should be monitored.

PREGNANCY: Although colesevelam has not been studied in pregnant women, it has not been shown to cause birth defects or other problems in animal studies.

NURSING MOTHERS: It is not known whether colesevelam passes into breast milk, but very little colesevelam is absorbed from the intestine and is available for secretion in breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breastfeeding. Colesevelam may decrease the absorption of certain vitamins, which are important during breastfeeding. Mothers who are taking colesevelam and who wish to breast-feed should discuss this with their doctor.

SIDE EFFECTS: Colesevelam usually is well-tolerated. Side effects may include constipation, upset stomach, indigestion, headache, stomach pain, or diarrhea.

Reference: FDA Prescribing Information

Last Editorial Review: 1/5/2011

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