Optimal - The Blog
May 6, 2024
A number of individuals receiving stand-along T4 thyroid hormone therapy report persistent symptoms... A combination of T4 + T3 therapy may help...
Considerable research interest has focused on administration of combinations of T4 and T3 to a patient with symptoms of hypothyroidism that are apparently refractory to LT4 (31).
An initial double-blind, randomized trial in patients with hypothyroidism demonstrated improvements in mood and neuropsychological function in patients for whom T3 was given in place of a proportion of their LT4 dose.
Further evidence from randomized or observational studies has supported the possibility of significant differences in quality of life (QoL) scores or psychological scores in favor of the combination vs LT4 monotherapy.
Typical symptoms of hypothyroidism.
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Examples of medical conditions or treatments that produce symptoms resembling hypothyroidism |
Typical symptoms resembling those of hypothyroidism |
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Chronic fatigue GI diseases that affect LT4 absorption Addison’s disease Anemia Stress Changes in weight Pregnancy Medications that interfere with LT4 absorptiona |
Constipation Puffy eyes Hoarse/deep voice Muscle cramps Hair loss or dry hair Dry or scaly skin Muscle weakness Carpal tunnel syndrome |
Feeling too cold Slow thinking Tired/lethargic Weight gain Depression Loss of libido Menstrual abnormalities Poor memory |
Overview of management of patients with hypothyroidism who continue to report symptoms of that condition despite receiving levothyroxine therapy.
Pragmatic approach to managing a patient with continued symptoms of hypothyroidism despite apparently adequate levothyroxine therapy.
- Take a thorough medical history
- Careful initial examination to identify potential other causes for hypothyroid-like symptoms
- Check the diagnosis of hypothyroidism and lab results
- Ensure TSH is well controlled first
Check for patient factors and concomitant drug treatments that might have interfered with the TSH assay - Check for sub-optimal compliance
- Is the patient taking all required doses?
- Check for factors that could alter the metabolism of thyroid hormones
- Potential for malabsorption of LT4
Some treatments affect thyroid hormone metabolism - Check how the patient uses LT4
- Does the patient take LT4 in the fasting state at the start of the day, as per label?
- Does the patient adjust the timing of other therapies that could interfere with LT4 absorption?
- Is the patient storing their LT4 correctly?
- Does the patient have the correct LT4 tablets, as per prescription?
Personalized treatment with LT4 + LT3 may be of benefit for some patients with persistent symptoms of hypothyroidism such as those with polymorphisms in the deiodinase enzyme 2 (DIO2)
Reference
Razvi, Salman et al. “Managing symptoms in hypothyroid patients on adequate levothyroxine: a narrative review.” Endocrine Connections vol. 9,11 (2020): R241-R250. doi:10.1530/EC-20-0205. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Learn More about the mysteries of thyroid function and dysfunction:
Thyroid Hormones and Glucose Regulation: A Close Relationship
Thyroid Dysfunction and Movement Disorders
