Oral liquid levothyroxine treatment at breakfast: a mistake?

Taking levothyroxine (L-T₄) with coffee or with water followed by coffee intake within a few minutes results in poor TSH response in many patients. T₄ is available in tablet form worldwide, but novel formulations in soft gel capsule or liquid form are now available.

We fortuitously identified a euthyroid patient who wrongly consumed liquid L-T₄ with coffee at breakfast; after changing the time of consumption to 30 min before breakfast, no change in TSH, free T₄ (fT₄), and free tri-iodothyronine (fT₃) concentrations was observed. Once the first patient was identified, additional stable euthyroid patients who consumed liquid L-T₄ with coffee were identified.

Patients were recruited by searching our 'thyroid patients' database. All the patients on liquid L-T₄ treatment were contacted by phone to ask them whether they took L-T₄ at breakfast. We identified 54 patients who were submitted to TSH, fT₄, and fT₃ evaluation, with the indication that the same dosage of L-T₄ be consumed 30 min before breakfast. We determined their TSH, fT₄, and fT₃ concentrations after 3 and 6 months again.

no significant difference in thyroid hormone concentrations was observed in patients when they consumed L-T₄ at breakfast or when they consumed it 30 min before breakfast for 3 and 6 months (TSH: 2.5±1.1 vs 2.5±1.1 and 2.4±1.1 mIU/l respectively, fT₄: 12.4±2.4 vs 12.5±2.4 and 12.3±2.1 pg/ml respectively, and fT₃: 3.4±0.6 vs 3.4±0.6 and 3.3±0.5 pg/ml respectively).

Oral liquid L-T₄ formulations could diminish the problem of L-T₄ malabsorption caused by coffee when using traditional tablet formulations.