A Study of Colesevelam for Lenalidomide-Associated Diarrhea

For treatment with colesevelam, the starting dose will be 1250 mg (2 x 625 mg) with food which can be increased to 6 tablets max per day based on efficacy and tolerability. Coleveselam should not be taken within 4 hours before or after lenalidomide and other interacting medications. All participants will be given a pill diary to record intake of colesevelam. The effect of colesevelam on lenalidomide-associated diarrhea will be evaluated after 1, 2, 4, 12 weeks after start of treatment. If the diarrhea does not respond to the starting dose of colesevelam, the dose can be increased every 2 days to 2 tablets two times per day (2 x 625 mg BID) and later to 3 tablets two times per day (3 x 625 mg BID). The colesevelam dose can be decrease to 1 tablet per day if there has been improvement of diarrhea but emergence of side effects.