Certain drugs may interact poorly when taken with thyroid medications. Patients are urged to consult their physician before taking any additional prescriptions, over-the-counter medications, nutritional supplements or herbal medications.

Certain medications can alter the amount of thyroid hormone that a patient requires for the hormone to be effective. Such medications include birth control pills, estrogen, testosterone or other androgens, anticonvulsants (seizure medications), antidepressants and cholesterol drugs.

Other drugs that may interact with thyroid medications include:

• Anticoagulants (drugs that hinder blood clotting)
• Antihypertensives
• Antidiabetic agents
• Aspirin and other salicylates
• Oral corticosteroids
• Some heart drugs (e.g., digoxin)
• Some HIV drugs (e.g., efavirenz)
• Human growth hormone
• Insulin