From the Research
If your TSH is low while taking Synthroid (levothyroxine), you should consult your healthcare provider for proper guidance, and typically, dose reductions range from 12.5 to 25 micrograms (about 10-20% of your current dose), depending on how low your TSH is and your current symptoms, as suggested by recent clinical guidelines 1. When considering a dose reduction, it's essential to take into account the patient's age, as TSH goals are age-dependent, with a 97.5 percentile (upper limit of normal) of 3.6 mIU/L for patients under age 40, and 7.5 mIU/L for patients over age 80 1. Some key points to consider when adjusting the dose include:
- The goal of treatment is to maintain TSH within the normal reference range (usually 0.4-4.0 mIU/L, though this varies by lab and age) 1.
- Low TSH indicates potential overtreatment with thyroid hormone, which can lead to symptoms like anxiety, rapid heartbeat, insomnia, and increased risk of osteoporosis or heart problems if left uncorrected 2.
- Thyroid medication requires precise dosing, and factors like weight changes, other medications, and health conditions can affect how much medication you need 1.
- Your doctor will likely recommend blood tests 6-8 weeks after any dose adjustment to ensure your thyroid levels are moving in the right direction 1. It's also important to note that some patients may benefit from combination therapy with levothyroxine and liothyronine, especially those with a polymorphism in type 2 deiodinase, as suggested by recent studies 3, 4. However, the decision to adjust the dose or switch to combination therapy should be made under the guidance of a healthcare provider, taking into account the individual patient's needs and medical history.