13/08/2025
Important reminders for those on levothyroxine treatment.
ETA guidelines for the use of levothyroxine to optimize the treatment of hypothyroidism: recently, an expert task force was approved by the Guidelines Board of the European Thyroid Association to formulate recommendations for patients who take levothyroxine in tablet form:
For optimal absorption of levothyroxine, tablet form:
🔹absorption of levothyroxine is under fasting conditions, with 62–82% of the dose absorbed during the first 3 hours after ingestion
🔹soy, coffee, tea, milk, and grapefruit may interfere with absorption; avoid these for a few hours after taking the medication
🔹 calcium, iron may interfere with absorption; take these 4 hours apart from levothyroxine
🔹a fiber-enriched diet or fiber supplements may cause malabsorption
📍Drug interaction with levothyroxine absorption:
🔹proton pump inhibitors, PPIs, (rabeprazole, esomeprazole, omeprazole, pantoprazole, lansoprazole) used for gastritis, stomach-related conditions, may interfere with absorption. Take levothyroxine at least 4 h before PPI.
🔹patients with gastric disorders and those who take proton pump inhibitors may require higher levothyroxine doses to achieve target TSH levels, and long-term PPI administration presents a heightened risk in these cases. Always mention gastric issues and medication taken for these to your doctor.
📍The co-prescription of levothyroxine with several interacting drugs (Tamoxifen, estrogens, corticosteroids, etc) or supplements can affect bioavailability; always discuss with the doctor both the medications and supplements taken.
📍Regular thyroid function lab tests as markers of adequate thyroid hormone status are important.
📍An effective doctor–patient relationship is essential to individualize treatment and reach the therapeutic goal.
Marco Centanni, Leonidas Duntas, Ulla Feldt-Rasmussen, Josef Koehrle, Robin P Peeters, Salman Razvi, Pierpaolo Trimboli, Camilla Virili. ETA guidelines for the use of levothyroxine sodium preparations in monotherapy to optimize the treatment of hypothyroidism. European Thyroid Journal. July. 2025.