Over-the-counter-drug-induced thyroid disorders

Endocr Pract. 2013 Mar-Apr;19(2):268-74. doi: 10.4158/EP12298.OR.


Objective: Excessive iodine ingestion may cause thyroid dysfunction. In this case series, we report four patients who developed significant thyroid dysfunction after ingesting over-the-counter (OTC) drugs containing large concentrations of iodine.

Methods: Four patients from a tertiary medical center are reported.

Results: Case 1 involved acute exacerbation of thyrotoxicosis induced by taking OTC Tri-iodine™ in a 35-year-old woman while still on methimazole therapy. Case 2 involved thyroid-extract-induced thyrotoxicosis following ingestion of Thyromine™, and was confirmed by laboratory studies and ¹³¹I thyroid uptake. Cases 3 and 4 involved severe, symptomatic hypothyroidism induced in 2 patients with underlying autoimmune thyroiditis (Hashimoto's disease) following ingestion of Iodoral™. In all cases, thyroid dysfunction resolved with appropriate management and discontinuation of the OTC drugs.

Conclusion: These case reports demonstrate the significant risks associated with OTC preparations containing iodine in patients predisposed to thyroid dysfunction. There is no valid reason for taking high-dose OTC iodine supplements, which have been shown to cause harm and have no known benefit.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Dietary Supplements / adverse effects*
  • Female
  • Humans
  • Hypothyroidism / blood
  • Hypothyroidism / etiology
  • Hypothyroidism / physiopathology
  • Hypothyroidism / therapy
  • Iodine / blood
  • Iodine / poisoning*
  • Maryland
  • Middle Aged
  • Potassium Iodide / adverse effects
  • Thyroid (USP) / adverse effects
  • Thyroid Diseases / blood
  • Thyroid Diseases / etiology*
  • Thyroid Diseases / physiopathology
  • Thyroid Diseases / therapy
  • Thyroid Gland / physiopathology*
  • Thyrotoxicosis / blood
  • Thyrotoxicosis / etiology
  • Thyrotoxicosis / physiopathology
  • Thyrotoxicosis / therapy
  • Treatment Outcome


  • Thyroid (USP)
  • Potassium Iodide
  • Iodine