Drug General Information (ID: DDI5JKSWZI)
Drug Name			Levothyroxine		Drug Info		Iodide I-131		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antithyroid Agents				Radiopharmaceuticals
Structure

Mechanism of Levothyroxine-Iodide I-131 Interaction (Severity Level: Moderate)
Interference of cell/tissue uptake Click to Show/Hide Mechanism Graph
Drug Name		Levothyroxine				Iodide I-131
Mechanism		Interfere with the therapeutic effect and/or diagnostic result of radioiodides				Radioiodide
Key Mechanism Factor 1
		Factor Name		Pharmacokinetics
		Factor Description		Alters the distribution of the drug, leading to changes in the plasma concentration of the drug and affecting the pharmacological effects.
Mechanism Description		Interference of cell/tissue uptake of Iodide I-131 by Levothyroxine

Recommended Action
Management		Liothyronine (triiodothyronine) should be withheld for at least 10 days and levothyroxine (thyroxine) for 6 weeks before administering sodium iodide I-131 or I-123, and for 2 weeks after treatment.

References
1	EMEA. European Medicines Agency "EPARs. European Union Public Assessment Reports.".
2	Lampe WT "Hypoglycemia due to acetohexamide." Arch Intern Med 120 (1967): 239-41. [PMID: 4952678]
3	Multum Information Services, Inc. Expert Review Panel.