Increase Synthroid to 200 mcg Daily
Your TSH of 6.890 uIU/mL indicates inadequate thyroid hormone replacement, and you need a dose increase of 25 mcg to bring your TSH into the target range of 0.5-4.5 uIU/mL. 1, 2
Why This Dose Increase Is Necessary
Your current situation shows:
- TSH is elevated at 6.890 uIU/mL (normal range: 0.45-4.5 uIU/mL), indicating your body needs more thyroid hormone 1
- Free T4 is normal at 1.29 ng/dL (range: 0.82-1.77), which defines this as subclinical hypothyroidism requiring treatment adjustment 1
- You're already on a high dose (175 mcg), suggesting either poor absorption, medication interactions, or increased metabolic needs 3
The Recommended Dose Adjustment
Increase your Synthroid from 175 mcg to 200 mcg daily (a 25 mcg increment). 1, 2
This increment size is appropriate because:
- For patients with TSH between 4.5-10 mIU/L, a 12.5-25 mcg increase is recommended 1
- Given your TSH is 6.890 (closer to 7), a 25 mcg increase is justified to normalize your levels more efficiently 2
- Larger adjustments should be avoided as they risk iatrogenic hyperthyroidism, especially in elderly patients or those with cardiac disease 1
Critical Monitoring After Dose Change
Recheck TSH and Free T4 in exactly 6-8 weeks after starting the new dose. 1, 4
This timing is essential because:
- Levothyroxine requires 4-6 weeks to reach steady state in your body 4
- Testing earlier will give falsely abnormal results 1
- Testing later delays necessary adjustments 1
Important Medication Administration Rules
To ensure proper absorption of your increased dose:
- Take on an empty stomach, 30-60 minutes before breakfast with a full glass of water 4, 5
- Wait at least 4 hours before taking iron, calcium supplements, or antacids, as these block levothyroxine absorption 4
- Avoid soybean products, grapefruit, and high-fiber foods within 1 hour of your dose 1
Common Causes of Persistent TSH Elevation
If your TSH remains elevated after this adjustment, consider:
- Poor medication compliance (most common cause) 3
- Medications interfering with absorption: proton pump inhibitors, iron, calcium, bile acid sequestrants 4, 3
- Malabsorption conditions: celiac disease, inflammatory bowel disease, gastric bypass 3
- Increased levothyroxine requirements: pregnancy, weight gain, certain medications like estrogen or rifampin 1, 3
What Happens If You Don't Increase the Dose
Leaving your TSH elevated at 6.890 carries real risks:
- 5% annual risk of progression to overt hypothyroidism 1
- Persistent hypothyroid symptoms: fatigue, weight gain, cold intolerance, constipation 1, 5
- Adverse cardiovascular effects: abnormal cardiac output, delayed relaxation, elevated LDL cholesterol 1
- Reduced quality of life from untreated symptoms 1
Critical Pitfall to Avoid
Never assume your symptoms are unrelated to the elevated TSH. Even "subclinical" hypothyroidism with TSH >7 mIU/L frequently causes symptoms and warrants treatment, especially in patients already on replacement therapy. 1, 6
Long-Term Goal
Your target TSH should be 0.5-2.5 uIU/mL (lower half of normal range) with normal Free T4 levels. 1, 6 Once stable on the correct dose, you'll need annual TSH monitoring to ensure continued adequacy of replacement. 1