Drug General Information (ID: DDIJ0263XH)
Drug Name			Levothyroxine		Drug Info		Amiodarone		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antithyroid Agents				Antiarrhythmic Agents
Structure

Mechanism of Levothyroxine-Amiodarone Interaction (Severity Level: Moderate)
Attenuated pharmacological effects (Unspecific) Click to Show/Hide Mechanism Graph
Drug Name		Levothyroxine				Amiodarone
Mechanism		Thyroid hormone				Reduce the effects of exogenous thyroid hormones
Key Mechanism Factor 1
		Factor Name		Pharmacodynamics
		Factor Description		Reduced pharmacological effects leading to insufficient efficacy and/or treatment failure.
Mechanism Description		Attenuated pharmacological effects of  Levothyroxine when combined with Amiodarone

Recommended Action
Management		Therapy with amiodarone should be administered cautiously in patients with thyroid dysfunction. Clinical monitoring, including baseline and periodic (every 6 months) laboratory evaluation of thyroid function is recommended during concomitant treatment and for several months after discontinuation of amiodarone, especially in elderly patients. Modification of therapy may be necessary.

References
1	Product Information. Cordarone (amiodarone). Wyeth-Ayerst Laboratories, Philadelphia, PA.
2	Product Information. Synthroid (levothyroxine). Abbott Pharmaceutical, Abbott Park, IL.
3	Singh BN, Nademanee K "Amiodarone and thyroid function: clinical implications during antiarrhythmic therapy." Am Heart J 106 (1983): 857-69