How the interaction occurs:
Colesevelam may bind to your oral contraceptive in your GI tract, preventing your body from absorbing the medicine.
What might happen:
The amount of contraceptive in your blood may decrease and it may not work as well.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. You should time your medicines so that you take your oral contraceptive 4 hours or more before your colesevelam. If you have any questions about how to take your medicines, ask your pharmacist.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Welchol (colesevelam hydrochloride) US prescribing information. Daiichi Sankyo, Inc. July, 2012.
2.Brown KS, Armstrong IC, Wang A, Walker JR, Noveck RJ, Swearingen D, Allison M, Kissling JC, Kisicki J, Salazar DE. Effect of the bile acid sequestrant colesevelam on the pharmacokinetics of pioglitazone, repaglinide, estrogen estradiol, norethindrone, levothyroxine, and glyburide. J Clin Pharmacol 2010 May;50(5):554-65.