From the Guidelines
Several medications and supplements can raise thyroid-stimulating hormone (TSH) levels, including lithium, amiodarone, certain anti-epileptic drugs, glucocorticoids, iodine supplements, soy products, iron and calcium supplements, and some antidepressants.
Medications and Supplements that Raise TSH Levels
- Lithium, commonly used for bipolar disorder, can increase TSH by inhibiting thyroid hormone release 1.
- Amiodarone, a heart rhythm medication, contains high iodine levels that can disrupt thyroid function 1.
- Certain anti-epileptic drugs like carbamazepine and phenytoin can accelerate thyroid hormone metabolism, leading to elevated TSH 1.
- Glucocorticoids (prednisone, dexamethasone) can suppress TSH initially but cause rebound increases when discontinued 1.
- Iodine supplements, especially in excessive amounts, can paradoxically inhibit thyroid hormone production through the Wolff-Chaikoff effect 1.
- Soy products, when consumed in large quantities, may interfere with thyroid hormone absorption 1.
- Iron and calcium supplements can reduce thyroid medication absorption if taken simultaneously, potentially raising TSH in treated hypothyroid patients 1.
- Some antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), may also affect thyroid function 1. If you're taking any of these medications or supplements and experience symptoms like fatigue, weight gain, or cold intolerance, consult your healthcare provider for thyroid function testing, as dosage adjustments of either your thyroid medication or the interfering substance may be necessary 1.
From the Research
Medications that can Raise TSH
- Lithium: Lithium inhibits thyroid hormone release and increases TRH-stimulated TSH, inducing goiter, clinical and subclinical hypothyroidism, and hyperthyroidism 2, 3.
- Nonphenothiazines (typical antipsychotics): can induce the formation of thyroid autoantibodies and can elevate TSH levels 2.
- Certain antidepressants: Tricyclic antidepressant drugs can complex with iodine and thyroid peroxidase and deactivate them, induce deiodinase activity and interfere with the hypothalamo-pituitary-thyroid (HPT) axis by decreasing TSH response to TRH, however some studies suggest certain antidepressants may have the opposite effect 2, 4.
Supplements and Other Substances
- There is limited information available on supplements that can raise TSH, however it is known that certain substances such as iodine can affect thyroid function 3.
Important Considerations
- Patients receiving lithium, phenothiazines, and tricyclic antidepressants should be closely monitored for the development of thyroid function abnormalities 2.
- Patients with a history of thyroid disorders or those taking certain medications such as carbamazepine may need to have their thyroid function monitored 5, 6.