Endocrine Abstracts

Many conditions may interfere with intestinal absorption of levothyroxine (L-T₄). In addition, it has been demonstrated a failure in the normalisation of TSH values in patients consuming L-T₄ tablets with coffee or with water followed by coffee taken shortly afterwards. Recent studies showed that oral liquid L-T₄ could remove the problem of L-T₄ malabsorption by coffee and food observed with traditional tablets formulations. To evaluate the efficacy of oral liquid T₄ assumed at breakfast, we conducted the TICO study: a double-blind, placebo-controlled trial, designed to enrolled 80–100 hypothyroid patients, aged from 18 to 75 years who have to start replacement therapy. All the patients were given two identical and indistinguishable vials (labelled A and B), one containing in a single dose of the oral solution and the other a placebo; one had to be assumed half an hour before breakfast and the other one during their usual breakfast. After 40 days of treatment, all the patients were submitted to TSH, fT₄, and fT₃ evaluation to ensure euthyroidism values had been reached. All the patients then had to switch the order in which the vial contents were ingested. After 40 days, TSH, fT₄, and fT₃ values were re-tested. At this time 72 patients (54/18 females/males, mean age 48.8±5.7 years old) completed the study. The mean dose of L-T₄ was 64.71±30.17 μg/day. At the end of the study no differences to TSH serum (2.84±1.91 mlU/l vs 2.62±1.76 mlU/l, P=0.470), fT₄ (10.57±1.32 pg/ml vs 10.44±1.24 pg/ml, P=0.546), and fT₃ (2.75±0.36 pg/ml vs 2.85±0.28 pg/ml, P=0.193) were observed among the patients whether assuming vials A or vials B at breakfast. In conclusion, we have clearly demonstrated that liquid L-T₄ can be taken at breakfast, facilitating compliance to L-T₄ replacement therapy. Finally, the oral solution L-T₄ could be suitable for patients who cannot swallow the solid formulations.