Drugs Home > Drug Interactions With Colesevelam

Colesevelam may decrease the absorption of olmesartan into the body, perhaps making it less effective. Olmesartan should be taken at least four hours before a dose of colesevelam to avoid this interaction. If you take colesevelam twice a day and have trouble timing the doses of olmesartan and colesevelam, ask your healthcare provider about taking colesevelam just once a day instead of twice a day, as this can help make avoiding this interaction easier.
Oral Contraceptives
Colesevelam has been shown to decrease the absorption of certain birth control pills (those that contain ethinyl estradiol in combination with norethindrone), perhaps increasing the risk of pregnancy. Colesevelam has not been studied in combination with other birth control pills, and it is likely to interact similarly with other birth control pills as well. Birth control pills should be taken at least four hours before a dose of colesevelam.
Phenytoin (Dilantin, Phenytek)
There have been reports of colesevelam interacting with phenytoin, decreasing its absorption and perhaps making it less effective. In order to avoid this interaction, take phenytoin at least four hours before a dose of colesevelam.
Warfarin (Coumadin, Jantoven)
Although there have been reports that colesevelam may interact with warfarin, studies have not demonstrated any interaction between these two medications. Interactions may occur due to a decreased absorption of vitamin K, since vitamin K can affect warfarin. Check with your healthcare provider in this situation, as you may need to be monitored more closely.

Final Thoughts on Drug Interactions With Colesevelam

It is possible that not all drug interactions were discussed in this article. Therefore, you should talk with your pharmacist or healthcare provider about the possible drug interactions with colesevelam that may apply to you.
Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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