Oral liquid levothyroxine treatment at breakfast: a mistake?

ObjectiveTaking levothyroxine (l-T4) with coffee or with water followed by coffee intake within a few minutes results in poor TSH response in many patients. T4is available in tablet form worldwide, but novel formulations in soft gel capsule or liquid form are now available.DesignWe fortuitously identified a euthyroid patient who wrongly consumed liquidl-T4with 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 liquidl-T4with coffee were identified.MethodsPatients were recruited by searching our ‘thyroid patients’ database. All the patients on liquidl-T4treatment were contacted by phone to ask them whether they tookl-T4at breakfast. We identified 54 patients who were submitted to TSH, fT4, and fT3evaluation, with the indication that the same dosage ofl-T4be consumed 30 min before breakfast. We determined their TSH, fT4, and fT3concentrations after 3 and 6 months again.ResultsNo significant difference in thyroid hormone concentrations was observed in patients when they consumedl-T4at 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).ConclusionOral liquidl-T4formulations could diminish the problem ofl-T4malabsorption caused by coffee when using traditional tablet formulations.