Drug General Information (ID: DDIX37HNRY)
Drug Name			Liotrix		Drug Info		Ferrous sulfate anhydrous		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Thyroid Drugs				Iron Supplement
Structure

Mechanism of Liotrix-Ferrous sulfate anhydrous Interaction (Severity Level: Moderate)
Complex formation Click to Show/Hide Mechanism Graph
Drug Name		Liotrix				Ferrous sulfate anhydrous
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 Ferrous sulfate anhydrous due to formation of complexes caused by Liotrix

Recommended Action
Management		Some experts recommend separating the times of administration of levothyroxine and iron-containing preparations by at least 2 to 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	Campbell NR, Hasinoff BB, Stalts H, Rao B, Wong NC "Ferrous sulfate reduces thyroxine efficacy in patients with hypothyroidism." Ann Intern Med 117 (1992): 1010-3. [PMID: 1443969]
2	Product Information. Armour thyroid (thyroid desiccated). Forest Pharmaceuticals, St. Louis, MO.
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]