Increase Your Levothyroxine Dose Immediately
Your current levothyroxine dose of 200mcg is insufficient, as evidenced by your TSH of 18 mIU/L, and you need an immediate dose increase of 25mcg to 225mcg daily. 1, 2
Why Your Current Dose Is Failing
Your TSH of 18 mIU/L represents severe inadequate thyroid hormone replacement that carries approximately 5% annual risk of progression to worsening hypothyroidism and is associated with adverse cardiovascular effects, abnormal lipid metabolism, and significantly impaired quality of life 1. This level of TSH elevation demands prompt intervention regardless of symptoms 1.
Immediate Action Required
Increase your levothyroxine dose by 25mcg to a total of 225mcg daily 1, 2. This increment is appropriate for patients already on higher doses like yours, and will move you toward the target TSH range of 0.5-4.5 mIU/L 1, 2.
Critical Issues to Address Before Dose Adjustment
Before increasing your dose, you must rule out several common causes of treatment failure:
Medication Timing and Absorption
- Take levothyroxine on an empty stomach, 30-60 minutes before breakfast, and at least 4 hours apart from iron supplements, calcium, or antacids 1, 3
- Any deviation from this timing dramatically reduces absorption and explains persistent TSH elevation in many patients 3
Gastrointestinal Disorders
- Conditions like celiac disease, gastritis, Helicobacter pylori infection, or inflammatory bowel disease can reduce levothyroxine absorption by up to 50% 3
- If you have chronic digestive symptoms, testing for anti-tissue transglutaminase antibodies and H. pylori is warranted 3
Medication Interactions
- Iron, calcium supplements, proton pump inhibitors, bile acid sequestrants, and certain other medications significantly impair levothyroxine absorption 1, 3
- Review all your medications and supplements with your physician 3
Compliance Verification
- Confirm you are actually taking the medication daily as prescribed 1
- About 25% of patients on levothyroxine are either non-compliant or taking it incorrectly 1
Monitoring Protocol After Dose Increase
- Recheck TSH and free T4 in exactly 6-8 weeks after the dose increase 1, 2
- Do not recheck sooner, as levothyroxine takes this long to reach steady state 1
- Target TSH should be 0.5-4.5 mIU/L, ideally in the lower half of this range (0.5-2.5 mIU/L) 1, 4
If TSH Remains Elevated After Dose Adjustment
If your TSH remains above 10 mIU/L after 6-8 weeks on 225mcg despite confirmed adherence and proper timing:
- Increase the dose by another 12.5-25mcg 1
- Consider a levothyroxine absorption test to identify malabsorption 3
- Investigate for gastrointestinal pathology with gastroenterology consultation 3
- Measure free T4 alongside TSH to help interpret ongoing abnormal results 1
Critical Pitfalls to Avoid
- Never assume the problem is "just" non-compliance without investigating absorption issues and medication interactions 3
- Do not increase the dose by more than 25-50mcg at once, as excessive increases risk iatrogenic hyperthyroidism with atrial fibrillation and bone loss 1
- Do not recheck TSH before 6-8 weeks, as premature testing leads to inappropriate dose adjustments 1
- Never accept a TSH >10 mIU/L as adequate treatment, as this level carries significant cardiovascular and metabolic risks 1, 5
Long-Term Management
Once your TSH normalizes:
- Monitor TSH annually or sooner if symptoms change 1
- Maintain the same medication timing and avoid new supplements without checking interactions 3
- Recent evidence shows that mortality increases when TSH falls outside the normal reference range in either direction, making proper dosing critical for longevity 5
Special Consideration for Age and Cardiac Disease
If you are over 70 years old or have cardiac disease, use more conservative 12.5mcg increments instead of 25mcg to avoid precipitating cardiac complications 1. However, the goal remains normalization of TSH, not acceptance of persistent elevation 1.