Concurrent Administration of Lisdexamfetamine and Levothyroxine
Concurrent use of lisdexamfetamine (Vyvanse) and levothyroxine is permitted when clinically indicated. (accessdata.fda.gov) Levothyroxine labeling advises that concurrent sympathomimetic use may increase the effects of sympathomimetics or thyroid hormone, which warrants clinical monitoring. (accessdata.fda.gov)
Medication Timing Recommendations
Levothyroxine should be administered once daily on an empty stomach, typically 0.5 to 1 hour before breakfast. (accessdata.fda.gov) Levothyroxine should be administered at least 4 hours before or after drugs known to interfere with absorption, such as products containing iron or calcium supplements and some antacids. (accessdata.fda.gov) Vyvanse should be taken 1 time each day in the morning, with or without food. (dailymed.nlm.nih.gov) No specific levothyroxine–lisdexamfetamine dose separation is required by levothyroxine labeling. (accessdata.fda.gov)
Dosing Adjustments for Levothyroxine
Levothyroxine dose requirements should be individualized and adjusted based on periodic laboratory assessment and clinical response. (accessdata.fda.gov) No lisdexamfetamine-specific levothyroxine dose adjustment is specified in levothyroxine prescribing information. (accessdata.fda.gov) If symptoms or laboratory results suggest over-replacement or under-replacement, levothyroxine dose adjustment should be made and guided by serum TSH (and free T4 when indicated). (accessdata.fda.gov)
Dosing Adjustments for Lisdexamfetamine
No levothyroxine-specific lisdexamfetamine dose adjustment is specified in lisdexamfetamine prescribing information. (accessdata.fda.gov) Lisdexamfetamine is associated with increased blood pressure and heart rate, which should be monitored in all patients receiving therapy. (accessdata.fda.gov)
Monitoring Guidelines for Thyroid Function
Adults with primary hypothyroidism should have serum TSH monitored 6 to 8 weeks after any levothyroxine dose change. (accessdata.fda.gov) Adults on a stable and appropriate levothyroxine replacement dose should have clinical and biochemical response evaluated every 6 to 12 months, and whenever there is a change in clinical status. (accessdata.fda.gov) In the setting of therapy changes, persistent clinical or laboratory evidence of hypothyroidism despite an apparent adequate dose should prompt assessment for inadequate absorption, poor compliance, drug interactions, or combinations of these factors. (accessdata.fda.gov)
Monitoring Guidelines for Sympathetic/Cardiovascular Effects
Levothyroxine labeling states that concurrent use of sympathomimetics may increase the effects of sympathomimetics or thyroid hormone, including in settings where coronary insufficiency risk is a concern. (accessdata.fda.gov) Lisdexamfetamine labeling recommends monitoring for potential tachycardia and hypertension in all patients. (accessdata.fda.gov)
Monitoring and Dose-Adjustment Triggers in Practice
Levothyroxine dose should be reconsidered if thyroid status changes are suspected on the basis of symptoms and serum TSH trends. (accessdata.fda.gov) Levothyroxine administration should remain separated from interacting absorption agents (notably iron and calcium supplements and certain antacids) to avoid unintended under-replacement. (accessdata.fda.gov) Clinical reassessment is indicated when cardiovascular symptoms emerge while sympathomimetic therapy is used with levothyroxine. (accessdata.fda.gov)