Treatment pattern and frequency of serum TSH measurement in users of different levothyroxine formulations: a population-based study during the years 2009–2015

Abstract

Use of levothyroxine oral liquid formulations is increasing over time even though their use is still limited in a general population of Southern Italy. Our exploratory analysis showed that the frequency of thyroid-stimulating hormone measurement was reduced in patients switching from levothyroxine tablet to new formulations.

Expert opinion on liquid L-thyroxine usage in hypothyroid patients and new liquid thyroxine formulation — Tirosint SOL [Opinia ekspertów dotycząca stosowania płynnej postaci lewotyroksyny oraz nowego preparatu Tirosint SOL u chorych na niedoczynność tarczycy]

“…Four prospective studies with 200 participants evaluating replacement liquid LT4 therapy in hypothyroid patients and one population-based study with 56,354 patients treated with L-T4 mostly for hypothyroidism and non-toxic goitre were found [25][26][27][28][29]. In three out of four prospective studies including 185 subjects, switching from tablet LT4 to liquid LT4 appeared more effective; only in a single paper including 15 participants no difference in TSH between tablet and liquid LT4 formulations was noted [26].…”

“…In three out of four prospective studies including 185 subjects, switching from tablet LT4 to liquid LT4 appeared more effective; only in a single paper including 15 participants no difference in TSH between tablet and liquid LT4 formulations was noted [26]. In a population-based study of 56,354 levothyroxine users Ferrara et al found that the frequency of TSH measurement was reduced in patients switching from tablets to liquid levothyroxine formulation [28].…”

Drug interactions in users of tablet vs. oral liquid levothyroxine formulations: a real-world evidence study in primary care

“…These novel formulations display similar pharmacokinetic properties compared to LT4 tablets [17], and are resistant to gastric pH variations and are characterized by higher bioavailability [18][19][20]. These findings have been confirmed by recent clinical studies reporting significant reductions of TSH levels [21][22][23][24][25] and measurement frequency (as proxy of clinical efficacy) in patients switching from tablets to oral liquid LT4 formulations [26] in the absence of malabsorption or drug interference. In addition, oral liquid solutions of LT4, not requiring dissolution and speeding up the absorption as compared to tablets [17,18,27], have been demonstrated to circumvent LT4 malabsorption in cases of gastrointestinal diseases [28][29][30] and surgery [31,32].…”

Pharmacokinetics and Comparative Bioavailability of a Levothyroxine Sodium Oral Solution and Soft Capsule

“…Other reports showed better stabilization in the thyroid hormones profile with liquid thyroxine as opposed to tablet formulation. [35][36][37][38] In conclusion, the levothyroxine oral solution unit-dose ampules were bioequivalent to levothyroxine capsules within tightened confidence intervals when administered with or without water under fasting conditions. This new formulation may offer an additional treatment option for patients who have difficulty in swallowing solid dosage forms, potentially increasing patients' adherence to therapy.…”

“…It was also reported that oral liquid levothyroxine formulations could diminish the problem of levothyroxine malabsorption caused by lactose intolerance or Helicobacter pylori infection or bariatric surgery when using traditional tablet formulations. Other reports showed better stabilization in the thyroid hormones profile with liquid thyroxine as opposed to tablet formulation …”