Drug General Information (ID: DDILROMWGZ)
Drug Name			Levothyroxine		Drug Info		Lanthanum carbonate		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antithyroid Agents				Phosphate Binders
Structure

Mechanism of Levothyroxine-Lanthanum carbonate Interaction (Severity Level: Moderate)
Complex formation Click to Show/Hide Mechanism Graph
Drug Name		Levothyroxine				Lanthanum carbonate
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 Lanthanum carbonate due to formation of complexes caused by Levothyroxine

Recommended Action
Management		Levothyroxine should be administered at least 4 hours apart from phosphate binders. It is recommended that TSH levels be monitored more closely during concomitant use.

References
1	Cerner Multum, Inc. "UK Summary of Product Characteristics.".
2	Product Information. Renagel (sevelamer). Genzyme Corporation, Cambridge, MA.