If a patient's Thyroid-Stimulating Hormone (TSH) level is significantly elevated after missing levothyroxine (thyroxine) for over a week, should the dose be increased?

Management of Elevated TSH After Missing Levothyroxine for Over a Week

For a patient with elevated TSH after missing levothyroxine for over a week, you should resume the previous dose rather than immediately increasing it, as temporary non-adherence typically requires restoration of the established dose, not dose escalation. 1

Assessment of Elevated TSH After Medication Gap

• When a patient has missed levothyroxine for over a week, first confirm the elevation with repeat testing, as 30-60% of elevated TSH levels normalize on repeat testing 1
• Determine if the patient has symptoms of hypothyroidism (fatigue, cold intolerance, constipation, weight gain) which may have worsened during the medication gap 2
• Assess the degree of TSH elevation - levels >10 mIU/L represent a more significant deviation requiring closer monitoring 3

Resumption Protocol

• For most patients, resume the previously established dose of levothyroxine rather than increasing it immediately 4
• Allow 4-6 weeks for the peak therapeutic effect of the resumed dose to be achieved before considering dose adjustments 4
• Schedule TSH retesting 6-8 weeks after resuming the medication to assess adequacy of the current dose 1

Special Considerations

• For elderly patients (>60 years), resumption of the previous dose is particularly important to avoid cardiac complications from sudden dose increases 5
• If the patient has known cardiac disease, monitor closely for symptoms of cardiac ischemia or arrhythmia when resuming therapy 4
• Poor adherence is the most common cause of elevated TSH in patients on levothyroxine therapy - address barriers to medication adherence before considering dose adjustments 6

When to Consider Dose Adjustment

• Only consider dose increases if TSH remains elevated after 6-8 weeks of consistent medication adherence 1
• If dose adjustment is needed, increase by small increments (12.5-25 mcg) and retest TSH after another 4-6 weeks 4
• For patients with TSH >10 mIU/L that persists despite resumed therapy and confirmed adherence, dose adjustment may be warranted sooner 3

Monitoring Protocol

• Monitor TSH every 6-8 weeks while adjusting therapy until levels normalize 1
• Once stabilized, check TSH every 6-12 months to ensure ongoing adequacy of treatment 1
• Consider measuring free T4 along with TSH if the patient has persistent symptoms despite normalized TSH 1

Potential Pitfalls

• Increasing the dose prematurely can lead to overtreatment, risking osteoporosis, atrial fibrillation, and other symptoms of thyrotoxicosis, especially in elderly patients 7
• Failure to address adherence issues may lead to continued fluctuations in thyroid levels despite dose adjustments 8
• Missing doses for a week typically doesn't require dose adjustment, as the long half-life of levothyroxine (7 days) provides some buffer against short-term non-adherence 2