From the Research
To transition a patient from NP Thyroid to levothyroxine, start by calculating an equivalent dose based on T4 content, approximately 60-65 mcg of levothyroxine for every 60 mg of NP Thyroid (1 grain), as seen in the most recent and highest quality study available 1. When transitioning, consider the following key points:
- The conversion can be done directly by stopping NP Thyroid and starting levothyroxine the next day, though some clinicians prefer a gradual approach over 1-2 weeks to minimize fluctuations in thyroid hormone levels.
- Schedule thyroid function tests (TSH, free T4) 6-8 weeks after completing the transition to assess if dose adjustments are needed, as the body adjusts to the new medication and reaches a new equilibrium 2.
- Patients should be informed that they might experience temporary symptoms during the transition as the body adjusts to receiving T4 only instead of both T3 and T4.
- Morning administration of levothyroxine on an empty stomach, 30-60 minutes before breakfast or other medications, ensures optimal absorption. This conversion is necessary because levothyroxine provides more consistent blood levels and standardized dosing compared to natural thyroid preparations, though some patients may need T3 supplementation if they don't adequately convert T4 to T3, as suggested by research on the topic 3, 4. It's also important to note that the goal of treatment is to achieve euthyroidism, and the dose of levothyroxine may need to be adjusted based on the patient's individual needs and response to treatment, taking into account factors such as age, weight, and other health conditions 5.