Drug General Information (ID: DDI2GNZK68)
Drug Name			Levothyroxine		Drug Info		Methimazole		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antithyroid Agents				Antithyroid Agents
Structure

Mechanism of Levothyroxine-Methimazole Interaction (Severity Level: Moderate)
Attenuated pharmacological effects (Unspecific) Click to Show/Hide Mechanism Graph
Drug Name		Levothyroxine				Methimazole
Mechanism		Thyroid hormone				Antithyroid agent
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 Methimazole

Recommended Action
Management		Concomitant use of antithyroid agents and thyroid hormones should generally be avoided due to mutually negating effects.

References
1	Product Information. Armour thyroid (thyroid desiccated). Forest Pharmaceuticals, St. Louis, MO.
2	Product Information. Synthroid (levothyroxine). Abbott Pharmaceutical, Abbott Park, IL.
3	Wohlt PD, Zheng L, Gunderson S, Balzar SA, Johnson BD, Fish JT "Recommendations for the use of medications with continuous enteral nutrition." Am J Health Syst Pharm 66 (2009): 1438-67. [PMID: 19667002]