This tool facilitates the conversion between desiccated thyroid extract (Armour Thyroid being a common brand) and synthetic levothyroxine. It is designed to provide an estimated equivalent dosage when switching between these two thyroid hormone replacement medications. For example, a patient on a specific dosage of Armour Thyroid might use the calculation to determine a corresponding starting dose of levothyroxine, should their physician decide to switch medications.
The value of such a conversion lies in several areas. Levothyroxine is a synthetic T4 hormone and is often preferred due to its consistent potency, longer half-life, and lower cost. However, some patients find they do better on desiccated thyroid extract, which contains both T4 and T3 hormones. A conversion helps facilitate medication changes while minimizing potential disruptions in thyroid hormone levels. Historically, desiccated thyroid was a primary treatment option before synthetic options became widely available. Its continued use necessitates an understanding of equivalent doses for transitioning to or from synthetic T4.
