Deflazacort and Levothyroxine interaction
Deflazacort and Levothyroxine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Deflazacort (EMFLAZA) label · effective 2025-11-13
When concomitant administration of corticosteroids and levothyroxine is required, administration of corticosteroid should precede the initiation of levothyroxine therapy to reduce the risk of adrenal crisis.
In addition, patients with hypopituitarism, primary adrenal insufficiency or congenital adrenal hyperplasia, altered thyroid function, or pheochromocytoma may be at increased risk for adverse endocrine events.
Considerations for Use in Patients with Altered Thyroid Function Metabolic clearance of corticosteroids is decreased in hypothyroid patients and increased in hyperthyroid patients.
Changes in thyroid status of the patient may necessitate a dose adjustment of the corticosteroid.
From the Levothyroxine (Levothyroxine Sodium) label · effective 2024-07-10
Failure to do so may precipitate an acute adrenal crisis when thyroid hormone therapy is initiated, due to increased metabolic clearance of glucocorticoids by thyroid hormone.
Androgens/Anabolic Steroids Asparaginase Glucocorticoids Slow-Release Nictonic Acid These drugs may decrease serum TBG concentration.
Glucocorticoids (e.g., Dexamethasone ≥ 4 mg/day) Short-term administration of large doses of glucocorticoids may decrease serum T 3 concentrations by 30% with minimal change in serum T 4 levels.
However, long-term glucocorticoid therapy may result in slightly decreased T 3 and T 4 levels due to decreased TBG production (See above).
Nephrosis, severe hypoproteinemia, severe liver disease, acromegaly, androgens, and corticosteroids decrease TBG concentration.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.