Levothyroxine Dose Adjustment
Increase your levothyroxine dose by 12.5-25 mcg immediately, as your TSH of 4.42 mIU/L indicates inadequate thyroid hormone replacement that requires correction. 1
Why This Dose Adjustment Is Necessary
Your current TSH of 4.42 mIU/L is above the target range of 0.5-4.5 mIU/L for patients on levothyroxine therapy, indicating you are undertreated despite taking 100 mcg daily 1. Even though your free T4 of 1.2 ng/dL appears within normal limits, the elevated TSH definitively demonstrates insufficient thyroid hormone replacement 1.
The combination of elevated TSH with normal free T4 represents subclinical hypothyroidism in a patient already on treatment, which means your current dose is simply too low. 1
Specific Dose Adjustment Protocol
Recommended Increment
- Increase by 25 mcg if you are under 70 years old without cardiac disease, bringing your new dose to 125 mcg daily 1
- Increase by 12.5 mcg if you are over 70 years old or have cardiac disease, bringing your new dose to 112.5 mcg daily 1
The smaller increment for elderly or cardiac patients prevents potential cardiac complications from overly aggressive titration 1.
Monitoring Timeline
- Recheck TSH and free T4 in exactly 6-8 weeks after this dose change 1
- This 6-8 week interval is mandatory because levothyroxine requires this time to reach steady state in your system 1
- Do not recheck sooner, as premature testing leads to inappropriate dose adjustments before equilibrium is achieved 1
Target Goals
Your treatment aims for:
Once your TSH reaches this target range and remains stable, you'll only need annual monitoring unless symptoms change 1.
Why Your Current Situation Matters
Persistent TSH elevation above 4.5 mIU/L carries approximately 5% annual risk of progression to overt hypothyroidism 1. More importantly, inadequate replacement causes:
- Persistent hypothyroid symptoms including fatigue, weight gain, and cold intolerance 1
- Adverse cardiovascular effects such as abnormal cardiac output and delayed relaxation 1
- Unfavorable lipid metabolism with elevated LDL cholesterol 1
- Reduced quality of life that improves with proper replacement 1
Critical Pitfalls to Avoid
Never assume normal free T4 alone means adequate treatment—TSH is the primary marker for monitoring levothyroxine therapy, with sensitivity above 98% and specificity greater than 92% 1. Your elevated TSH definitively proves undertreatment regardless of the T4 level 1.
Do not make excessive dose increases—jumping to full replacement dose risks iatrogenic hyperthyroidism, which increases risk for atrial fibrillation, osteoporosis, and cardiac complications 1. Approximately 25% of patients on levothyroxine are unintentionally maintained on excessive doses, so measured titration is essential 1.
Avoid rechecking labs before 6-8 weeks—adjusting doses too frequently before reaching steady state leads to inappropriate management 1.
Special Considerations
If you have cardiac disease or are over 70 years old, use the smaller 12.5 mcg increment and monitor closely for angina, palpitations, or worsening heart failure during titration 1.
If you are planning pregnancy, more aggressive normalization of TSH is warranted, as subclinical hypothyroidism during pregnancy is associated with adverse outcomes including preeclampsia and low birth weight 1.
Before increasing your dose, ensure you are taking levothyroxine correctly: on an empty stomach, 30-60 minutes before breakfast, and at least 4 hours apart from iron, calcium supplements, or antacids 1.