Drug General Information (ID: DDI236L1PH)
Drug Name			Drospirenone		Drug Info		Cholestyramine		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Contraceptive Agents				Bile Acid Sequestrants
Structure

Mechanism of Drospirenone-Cholestyramine Interaction (Severity Level: Moderate)
Complex formation Click to Show/Hide Mechanism Graph
Drug Name		Drospirenone				Cholestyramine
Mechanism		Binds to anion exchange resin/polymer				Anion exchange resin/polymer
Key Mechanism Factor 1
		Factor Name		Chelation
		Factor Description		Chelation is a direct drug interaction that usually involves the formation of dimers or trimers, resulting in larger complexes and poorer absorption.
Mechanism Description		Decreased absorption of Cholestyramine due to formation of complexes caused by Drospirenone

Recommended Action
Management		Estrogens and/or progestin-containing oral medications should be administered at least one hour before or four to six hours after bile-acid binding resins such as cholestyramine, colestipol, and colesevelam. Patients receiving this combination should be advised to closely follow dosing schedules to prevent loss of therapeutic effects.

References
1	Agencia Espaola de Medicamentos y Productos Sanitarios Healthcare "Centro de informacion online de medicamentos de la AEMPS - CIMA.".
2	Arts CJM, Govers CARL, van den Berg H, Wolters MGE, van Leeuwen P, Thijssen JHH "In vitro binding of estrogens by dietary fiber and the in vivo apparent digestibility tested in pigs." J Steroid Biochem Mol Biol 38 (1991): 621-8. [PMID: 1645589]
3	Cerner Multum, Inc. "Australian Product Information.".
4	Cerner Multum, Inc. "Canadian Product Information.".
5	Product Information. Nextstellis (drospirenone-estetrol). Mayne Pharma, Greenville, NC.
6	Product Information. Questran (cholestyramine). Par Pharmaceutical Inc, Chestnut Ridge, NY.
7	Underhill KL, Rotter BA, Thompson BK, Prelusky DB, Trenholm HL "Effectiveness of cholestyramine in the detoxification of zearalenone as determined in mice." Bull Environ Contam Toxicol 54 (1995): 128-34. [PMID: 7756775]