Certain drugs can interact with your thyroid hormone to negatively affect your thyroid function. These are just a few commonly used medications that can affect your thyroid:

  • Amiodarone

  • Aspirin (more than 3,000 milligrams daily)

  • Oestrogen (for example, in hormone replacement therapy, or in the oral contraceptive pill)

  • Iron tablets

  • Iodine

  • Lithium

  • Propranolol

  • Corticosteroids