Oral liquid levothyroxine treatment at breakfast: a mistake?

OBJECTIVE:

Levothyroxine (L-T4) treatment with coffee, or with water followed by coffee within a few minutes, results in poor TSH response in many patients. Thyroxine is worldwide suitable in tablets form but novel formulations in soft gel capsule or liquid formulation are now available.

DESIGN:

We fortuitously observed an euthyroid patient who wrongly assumed liquid L-T4 with coffee at breakfast: after changing the assumption thirty minutes before breakfast, no change of TSH, fT4 and fT3 was observed. Once the first patient was identified, we identified additional stable euthyroid patients who assumed liquid L-T4 with coffee.

METHODS:

Patients were recruited by searching our "thyroid patients" database. All patients on liquid L-T4 treatment were contacted by phone to find out if L-T4 was taken at breakfast. We identified fifty-four patients that were submitted to TSH, fT4 and fT3 evaluation, with the following indication to assume the same dosage of L-T4 half hour before breakfast. We checked again their TSH, fT4 and fT3 values, 3 and 6 months later.

RESULTS:

No significative difference of thyroid hormonal values was observed between patients who assumed L-T4 at breakfast and after 3 and 6 months of its assumption half hour before breakfast [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].

CONCLUSION:

Oral liquid L-T4 could remove the problem of L-T4 malabsorption by coffee observed with traditional tablets formulations.