Drug General Information (ID: DDIIASR1XJ)
Drug Name			Liotrix		Drug Info		Simethicone		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Thyroid Drugs				Gi Agents
Structure

Mechanism of Liotrix-Simethicone Interaction (Severity Level: Moderate)
Complex formation Click to Show/Hide Mechanism Graph
Drug Name		Liotrix				Simethicone
Mechanism		Binds to polyvalent cations				Polyvalent cations
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 Simethicone due to formation of complexes caused by Liotrix

Recommended Action
Management		It is recommended to separate the times of administration of levothyroxine and simethicone and antacids or other antacid-containing preparations (e.g., didanosine buffered tablets or pediatric oral solution) by at least 4 hours. Monitoring of serum TSH levels is recommended. Patients with gastrointestinal or malabsorption disorders may be at a greater risk of developing clinical or subclinical hypothyroidism due to this interaction.

References
1	Neafsey PJ "Levothyroxine and calcium interaction: timing is everything." Home Healthc Nurse 22 (2004): 338-9. [PMID: 15131426]
2	Product Information. Synthroid (levothyroxine). Abbott Pharmaceutical, Abbott Park, IL.
3	Schneyer CR "Calcium carbonate and reduction of levothyroxine efficacy." JAMA 279 (1998): 750. [PMID: 9508149]