title: Oral liquid levothyroxine treatment at breakfast: a mistake?
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  Oral liquid L-T₄ formulations could diminish the problem of L-T₄ malabsorption caused by coffee when using traditional tablet formulations.
authors.affiliation: Endocrine and Metabolic Unit, Clinica Medica, Department of Clinical and Experimental Sciences, University of Brescia, c/o 1^ Medicina Spedali Civili di Brescia, Piazzale Spedali Civili no. 1, 25100 Brescia, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Cappelli
authors.forename: Ilenia
authors.initials: I
authors.lastname: Pirola
authors.forename: Elena
authors.initials: E
authors.lastname: Gandossi
authors.forename: Annamaria
authors.initials: A
authors.lastname: Formenti
authors.forename: Maurizio
authors.initials: M
authors.lastname: Castellano
mesh_terms: D000284:Administration, Oral; D000328:Adult; D062408:Breakfast; D003069:Coffee / Q000009:adverse effects*; D015331:Cohort Studies; D004334:Drug Administration Schedule; D005260:Female; D018565:Food-Drug Interactions; D020249:Hormone Replacement Therapy; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D007408:Intestinal Absorption; D007558:Italy; D008297:Male; D008875:Middle Aged; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D013997:Time Factors; D014284:Triiodothyronine / Q000097:blood
chemical_list: D003069:Coffee; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine