Skip to main content

PERSPECTIVE article

Front. Endocrinol., 08 January 2024
Sec. Thyroid Endocrinology
This article is part of the Research Topic Levothyroxine Therapy in Patients with Hypothyroidism: Volume II View all 9 articles

Levothyroxine personalized treatment: is it still a dream?

Carlo Cappelli*Carlo Cappelli1*Elisa GattaElisa Gatta1Salvatore IppolitoSalvatore Ippolito2
  • 1Department of Clinical and Experimental Sciences, SSD Endocrinologia, University of Brescia, ASST Spedali Civili of Brescia, Brescia, Italy
  • 2Consulcesi Homnya, Head of Omnichannel Strategy & Project Management, Rome, Italy

Levothyroxine is a milestone in the treatment of all causes of hypothyroidism. From 19th century till today, Levothyroxine experienced a great advancement, from hypodermic injections of an extract of the thyroid gland of a sheep to novel formulations, known to circumvent malabsorption issue. However, the rate of patients on suboptimal therapy is still high. Current Guidelines are clear, daily Levothyroxine dosage should be calculated based on body weight. However, we are still far away from the possibility to administer the right dosage to the right patient, for several reasons. We retrace the history of treatment with levothyroxine, pointing out strengths and weaknesses of different formulations, with particular attention to what keeps us away from tailored therapy. In the age of digitalization, the pharmaceutical industry has been giving rising importance to Digital therapeutics, that are known to be effective in reaching target therapies. By combining current knowledge of hypothyroidism therapy with cutting-edge technology, we also hypothesized what could be the future strategies to be developed in this field.

Introduction

Levothyroxine (L-T4) is a milestone in the treatment of all causes of hypothyroidism, being the second most common medication dispensed in the United States in the last few years (1, 2). The first documented effective myxedema treatment with hypodermic injections of an extract of the thyroid gland of a sheep dates back to the late 19th century (3). In 1926 thyroxine was synthetized (4), although L-T4 was commercially marketed in 1955. However, tablets of desiccated thyroid extract, containing both thyroxine and triiodothyronine, remained the primary therapy until 1970s (5). L-T4 tablets represented the unique available therapy for over 30 years, until novel formulations (liquid oral solution and softgel capsules) were produced and distributed in 2000s (6). Even if L-T4 treatment appears to be easy to manage (7), it has a narrow therapeutic index (8) so much so that almost 50% of treated patients show abnormality of thyroid hormone profile after one year of treatment (9), potentially leading to iatrogenic complications or hypothyroidism symptoms (10). Many causes could be responsible of it, among them the lack of dosages that can enable precision therapy. We retraced the history of treatment with L-T4, pointing out strengths and weaknesses of different formulations, up to dream a personalized L-T4 treatment.

The history

The thyroid gland’s significance was established in the 19th century, however the discovery of thyroid hormones dates back to the 20th century, and the treatment of hypothyroidism has been refined over the last century. In 1884, Moritz Schiff showed in animal models that the clinical effects of hypothyroidism following thyroidectomy significantly diminish when additional thyroid glands from an animal of the same species are introduced and implanted in the abdominal cavity beforehand (3). Some year later Bettencourt and Serrano apply this result in human, unfortunately the patient died three days after for titania (11). In the same years, George Murray reported the first case of myxedema treated successfully with hypodermic injections of an extract of the thyroid gland of a sheep (12, 13). In 1914, Edward Calvin Kendall and Edward L. Adkins extracted the hormone, namely thyroxine, from animal-derived desiccated thyroid glands. However, they did not determine its chemical structure (14). In 1926, Barger and Harington succeeded in synthesizing thyroxine (4). Although thyroxine was commercially marketed in 1955, tablets of desiccated thyroid extract, containing both thyroxine (T4) and triiodothyronine (T3) were commonly used until 1970s (5). Desiccated thyroid showed large variability in hormone content from batch to batch making difficult to achieve the consistent dosage and to maintain stable TSH levels (15, 16), and T3 concentrations could be fluctuating and often elevated, leading to the symptoms of hyperthyroidism (2, 17, 18). In light of these, in 1970s, the British endocrinologists felt compelled to warn against the use of desiccated thyroid (19). Twenty-five years later, the American Thyroid Association (ATA) Guidelines recommended against biological and synthetic thyroid hormone preparations containing T4 and T3 (20). Even today, the Guidelines of the most authoritative association do not recommend the use of desiccated thyroid extract, and they consider L-T4 monotherapy the preferred treatment (2, 2123). Thus, for 50 years now, the consumption of L-T4 grew up worldwide.

It is well known that approximately 60- 90% of the L-T4 is absorbed in the jejunum and ileum within three hours of ingestion (24), and absorption is maximal when it is taken on an empty stomach. Once absorbed, T3 is obtained through deiodination reactions of L-T4 by deiodinase enzymes in peripheral tissues (25). Liver is the major site of deiodination but also kidney plays a significant role in the peripheral metabolism of thyroxine (26), however multiple tissues are capable of T4 deiodination to T3, then restoring the body’s T3 reservoir (2733). The L-T4 half-life after L-T4 oral administration ranges from 6.2 to 7.5 days (34).

Indeed, the acid gastric pH is essential to dissolve the tablet, removing sodium ion and converting L-T4 into a lipophilic molecule (35). All the conditions altering acid gastric pH are in fact the main cause of serum TSH instability (9): hydrophilic sodium salt remains undissociated in hypochlorydic gastric conditions, thus less absorbed (36). For this reason, current Guidelines by a Task Force of the ATA recommend that L-T4 should be taken in a fasting state (2). In addition, many pathological conditions (i.e., autoimmune gastritis, Helicobacter pylori infection and bariatric surgery) and drugs (i.e., proton pump inhibitors, ferrous sulphate, and calcium carbonate) reduce L-T4 absorption by alkalization of gastric pH or, in the case of some medications, the binding into insoluble complexes (3741). In this view, ATA Guidelines suggest that L-T4 has to be taken away also from interfering drugs (2).

Hence, the need to provide an advanced therapy prompted pharmaceutical companies to develop new formulations: liquid oral solutions and softgel capsules (6). The first is composed only of L-T4 of variable concentrations and glycerin: no dissolution is therefore required thus immediately available for absorption (41). The latter is L-T4 dissolved in glycerin in an outer gelatin shell, providing protection from the variations of gastric pH and preventing the binding to other substances in the intestinal lumen (41). As theoretically expected, Yue et al. firstly demonstrated that liquid L-T4 reached systemic circulation faster than tablets, since dissolution is not needed before absorption starts (42). Going on, our group demonstrated that liquid L-T4 can be ingested directly at breakfast, with no significant difference of thyroid hormones profile (43, 44), improving patients’ compliance and quality of life (45, 46). Finally, liquid L-T4 formulations represent a milestone for patients diagnosed with condition that can somehow impair gastric acidity (39, 4755) and moreover, they can be taken simultaneously with drugs known to interfere with L-T4 absorption (37, 43, 5666). Few promising data are available about Softgel capsules (37). Recently a prospective study showed that soft gel capsule can circumvent malabsorption in presence of interfering drugs (64). However, more studies are needed to confirm these data.

Although there has been significant progress in the pharmacokinetics of levothyroxine, we are still far from personalized therapy. In fact, ATA Guidelines suggest a dosage of 1.6-1.8 μg/kg; higher doses of 2.0–2.1 μg/kg are required for patients on L-T4 suppressive therapy for differentiated thyroid cancer (2). Most available formulations come with predetermined dosages. Even if most recent formulations, such as Levotirsol® (IBSA Farmaceutici Italia), have been commercialized with a wide range of intermediate dosages, the possibility to administer to each patient the right dosage remains an unlikely scenario.

Discussion

Even though the management of hypothyroidism is generally considered straightforward, almost half of patients showed TSH serum levels indicating over- or under-treatment (67, 68).

Maintaining TSH levels within the normal range adjusted for age and comorbidities is crucial to avoid deleterious effects. In fact, on one side, the risk for inpatient admissions and deaths due to cardiovascular disease, dysrhythmias, and osteoporotic fractures is higher for patients on L-T4 with suppressed TSH values, especially in elder people and postmenopausal women (6971). On the other side, inadequate therapy is associated with dyslipidemia, atherosclerotic cardiovascular disease, and congestive heart failure, although likely to a less severe degree (7274).

Many causes could explain the difficulty in maintaining TSH within normal ranges through the years, and among them the absence of a tailored L-T4 dosage has to be considered.

What should the gold standard be for a personalized L-T4 treatment? The answer is simple: the possibility to have a dosage of 1.6-2.1 μg/kg as recommended by American Thyroid Association guidelines (2), a steady absorption with a good compliance. Up to today, we have not had the possibility to give L-T4 dosage tailored for the patient’s weight. Indeed, liquid formulation as drops (Tirosint®, IBSA Farmaceutici Italia) or oral solution (Tifactor®, I.B.N. Savio Italia) permits to be close to a satisfactory personalized treatment. In fact, each milliliter of Tifactor® contains from 5 mcg to 20 mcg of L-T4, whereas each Tirosint® oral drop contains 3.75 mcg of L-T4, that is a good but not perfect dosage. However, this therapeutic strategy does not enhance patients’ compliance since counting drops is not practical, in particular for elder and partially sighted patients.

In the ever-evolving age of digitalization, the pharmaceutical industry has been giving rising importance to Digital therapeutics (DTx), driven by the purpose of transforming digital technologies into treatments (75). These systems deliver evidence-based therapeutic interventions to patients that are driven by a software that is programmed to prevent, manage, alleviate or treat a medical disorder or disease (76). Digital therapeutics can be used independently or in combination with medications, devices, or other therapies (77). What is more effective in reaching target therapy than a digital system? Undoubtedly, the most direct beneficiaries of DTx are patients themselves, by improving their experience, outcomes, and the coordination of their care; but patients aren’t the only ones benefitting (78). In fact, DTx improve the capability of clinicians to monitor treatment and to obtain information about care and patients’ response, using data sharing between patients and healthcare professionals (79). Moreover, also healthcare systems can profit, by targeting underserved areas in healthcare and reducing the burden on healthcare systems, by preventing hospital visits, improving self-management or providing therapy remotely (79).

Future direction

Precision medicine, also known as personalized medicine, is an innovative approach for tailoring diseases that allows the selection of a treatment in order to provide the best result limiting or deleting side effects. In the last few years, the need to detect the right drug, with the right dosage at the right time to the right patient has increased the interest of pharmaceutical companies and researchers (80). This “revolution” has been spreading in health care, particularly in oncology, providing effective tailored therapeutic strategies based on epigenomic, proteomic, and genomic profiles of each patient (8185). Simultaneously, the growing development of medical engineering and miniaturizing devices, increased patients’ compliance and quality of life. An anecdotical example is the artificial pancreas: a closed-loop insulin injection system that continuously monitors glucose levels and automatically adjusts insulin injection in real time (86). This permits a better quality of life for patients (87), reducing hypoglycemia (88), improving therapeutic target achievement (89), but above all, reducing overall mortality (90). As it is well demonstrated for insulin pumps, health technologies are cost-effective (91): in front of a high upfront investment, several economic benefits can be obtained, in particular healthcare systems can display a reduction of direct and indirect costs.

By combining the need of target therapy for hypothyroid patients and the cutting-edge technology, our dream is represented by a compact, portable, automated, digital device able to administer to each patients the proper dosage of L-T4, namely TTPen (Figure 1). Try to think having a TTPen that is able to administer the perfect dosage needed.

Figure 1
www.frontiersin.org

Figure 1 Graphical aspect of TTPen. Caption: (A) Charger of TTPen: a high battery capacity rechargeable with universal power cable; (B) Levothyroxine pen-like dispenser, containing L-T4 vial and Bluetooth© connection system that interfaces with smartphones.

TTPen consists of a charger and a pen-like dispenser. The charger provides a high battery capacity, it can be recharged with universal power cable, and it recharges the dispenser daily. The pen-like dispenser consists of a slot carrying the L-T4 vial and the dispenser. Each vial contains the monthly amount of L-T4 for a hypothetic 80 kg patient; different vials dosages are available according to the requirement based on weight, from 1.6 mcg/kg to 2.1 mcg/kg.

TTPen is made up of a material able to maintain thermal stability when exposed to both hot and cold temperatures. This last property, together with small size, makes TTPen portable, comfortable, and versatile. The dispenser releases the correct dose once a day. TTPen interfaces via Bluetooth© with TTApp, an application for smartphone available both for clinicians and patients, that allows users to regulate, plan, and analyze L-T4 therapy. On one side, patients can set administration times and TTApp reminds them to assume L-T4 at the right time, with a further alarm if left on. Moreover, TTApp gives patients the opportunity to record symptoms possibly related to over- or undertreatment, and to mark TSH values. On the other side, on the basis of clinical and biochemical data, clinicians can regulate daily dosage remotely, making adjustments in order to ensure the perfect L-T4 delivery to patients. In addition, clinicians can suggest the timing of TSH dosage and TTApp reminds patients to perform blood exams. TTSystem (TTPen and its device) is also fitted with an alarm system advising patients if any error occurs or if the vial is running out. Finally, the data recorded by TTApp are transferred to data repository available for clinicians, according to current privacy legislation.

Forward thinking, this innovative technology can be implemented and adapted for Hospital setting. In fact, each hypothyroid inpatient is on L-T4 therapy at different dosages, and in each Department countless different dosages and formulations need to be stocked. This involves space consumption, excessive waste of paper and plastic, and increased risk of expired medicine. A larger TTPen, with larger vials, and an adapted TTApp could circumvent all these problems. Clinicians and nurses can register each patient and its daily dosage in TTApp; every morning the right L-T4 therapy can be administered to each patient in a semi-automatized way that minimizes error risk.

For sure, this innovative system makes hypothyroid patients reach the perfect personalized therapy. Another benefit, no less important, is represented by eco-sustainability. In fact, no more bulky packages are needed, no more great amounts of paper and plastic get wasted because each vial lasts about one month. The impact of this saving is minimal considering a patient, but, if we think to the great amount of hypothyroid patients, we can play our part in saving our world. If we extend this system to Hospitals, the great saving sticks up, and this should not be underestimated in the face of the global warming phenomenon.

Indeed, several difficulties could be found in the development of this system. Even though the technology seems similar or easier than the insulin pump one, development process requires the application of engineering knowledge, considerable financial allocations and a long pathway for obtaining needed authorizations. Recognizing the importance of these innovative strategies by pharmaceutical companies is a key point. However, as it is well demonstrated for insulin pumps, health technologies are cost-effective (91): in front of a high upfront investment, several economic benefits can be obtained, in particular healthcare systems can display a reduction of direct and indirect costs. This innovative product, improving self-management and providing therapy remotely, could reduce outpatients access; in fact, patients on stable L-T4 therapy don’t need any additional periodical clinical evaluation. In addition, ensuring a better target achieving, a significant reduction of the number of TSH measurement could be shown in trial based economic evaluations (92).

TTSystem is a simple, effective, and eco-sustainable system that could represent the starting point of a revolution in hypothyroid therapy. The development of a product that incorporates design, quality, and enables personalized therapy is a dream. Pharmaceutical industry should realize how this could comprehensively change the field of hypothyroidism and undertake the development and commercialization pathway overcoming the existing barriers hindering the adoption of Digital technologies.

Conclusion

TTSystem represents the opportunity to cross a personalized L-T4 treatment over the new century. If it is the right way to tailored therapy, why not think of a similar system adapted to other medications, such as many psychiatric treatments or antibiotics?

In fact, antibiotic resistance, a global public health emerging crisis, has necessitated innovative solutions to counter the growing threat of untreatable bacterial infections. It has been attributed to the overuse and misuse of antibiotics, mainly due to incorrect dosage (93, 94). In this view, “precision antibiotics” or “personalized antibiotic therapy”, could offer a ray of hope in the battle against resistant bacterial strains (95).

But let’s come back to the present… “Carlo wake up! You must take Your L-T4 treatment” “Oh, Salvatore, I was dreaming a TTPen” (Figure 2).

Figure 2
www.frontiersin.org

Figure 2 Carlo comes back to the present from his dream.

Data availability statement

The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding authors.

Author contributions

CC: Conceptualization, Writing – review & editing. EG: Writing – original draft. SI: Conceptualization, Writing – review & editing.

Funding

The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.

Acknowledgments

We are grateful to Carlo Fazzari, healthcare manager, for his technical support and for believing in our dream.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

References

1. Fuentes AV, Pineda MD, Venkata KCN. Comprehension of top 200 prescribed drugs in the US as a resource for pharmacy teaching, training and practice. Pharm (Basel). (2018) 6(2):43. doi: 10.3390/pharmacy6020043

CrossRef Full Text | Google Scholar

2. Jonklaas J, Bianco AC, Bauer AJ, Burman KD, Cappola AR, Celi FS, et al. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid (2014) 24(12):1670–751. doi: 10.1089/thy.2014.0028

PubMed Abstract | CrossRef Full Text | Google Scholar

3. Schiff M. Bericht über eine Versuchsreeihe betreffend die Wirkungen der Exstirpation der Schilddrüse. Archiv für Experimentelle Pathologie und Pharmakologie. (1884) 18:25–34.

Google Scholar

4. Harington CR, Barger G. Chemistry of thyroxine: constitution and synthesis of thyroxine. Biochem J (1927) 21(1):169.

PubMed Abstract | Google Scholar

5. Lindholm J, Laurberg P. Hypothyroidism and thyroid substitution: historical aspects. J Thyroid Res (2011) 2011:809341. doi: 10.4061/2011/809341

PubMed Abstract | CrossRef Full Text | Google Scholar

6. Colucci P, D'Angelo P, Mautone G, Scarsi C, Ducharme MP. Pharmacokinetic equivalence of a levothyroxine sodium soft capsule manufactured using the new food and drug administration potency guidelines in healthy volunteers under fasting conditions. Ther Drug Monit (2011) 33(3):355–61. doi: 10.1097/FTD.0b013e318217b69f

PubMed Abstract | CrossRef Full Text | Google Scholar

7. Virili C. [The malabsorption of levothyroxine: a kaleidoscope of comorbidities?]. Recenti Prog Med (2022) 113(6):15e–8e. doi: 10.1701/3827.38159

PubMed Abstract | CrossRef Full Text | Google Scholar

8. Shah RB, Collier JS, Sayeed VA, Bryant A, Habib MJ, Khan MA. Tablet splitting of a narrow therapeutic index drug: a case with levothyroxine sodium. AAPS PharmSciTech (2010) 11(3):1359–67. doi: 10.1208/s12249-010-9515-8

PubMed Abstract | CrossRef Full Text | Google Scholar

9. Perez CL, Araki FS, Graf H, de Carvalho GA. Serum thyrotropin levels following levothyroxine administration at breakfast. Thyroid (2013) 23(7):779–84. doi: 10.1089/thy.2012.0435

PubMed Abstract | CrossRef Full Text | Google Scholar

10. Del Duca SC, Santaguida MG, Brusca N, Gatto I, Cellini M, Gargano L, et al. Individually-tailored thyroxine requirement in the same patients before and after thyroidectomy: a longitudinal study. Eur J Endocrinol (2015) 173(3):351–7. doi: 10.1530/EJE-15-0314

PubMed Abstract | CrossRef Full Text | Google Scholar

11. Bettencourt R, Serrano J. Un cas de myxoedème traité par la greffe hypodermique du corps thyroïde d’un mouton. La Semaine Médicale. (1890) 10:294.

Google Scholar

12. Murray GR. Note on the treatment of myxoedema by hypodermic injections of an extract of the thyroid gland of a sheep. Br Med J (1891) 2(1606):796.

PubMed Abstract | Google Scholar

13. Murray GR. The life-history of the first case of myxoedema treated by thyroid extract. Br Med J (1920) 1(3089):359. doi: 10.1136/bmj.1.3089.359

PubMed Abstract | CrossRef Full Text | Google Scholar

14. Kendall EC. Reminiscences on the isolation of thyroxine. Mayo Clinic Proc (1964) 39:548–52.

Google Scholar

15. Taylor S. Thyroid extract. Lancet (1961) 1(7172):332–3. doi: 10.1016/S0140-6736(61)91499-4

PubMed Abstract | CrossRef Full Text | Google Scholar

16. Wool MS, Selenkow HA. Physiologic combinations of synthetic thyroid hormones in myxedema. Clin Pharmacol Ther (1965) 6(6):710–5. doi: 10.1002/cpt196566710

PubMed Abstract | CrossRef Full Text | Google Scholar

17. Jackson IM, Cobb WE. Why does anyone still use desiccated thyroid USP? Am J Med (1978) 64(2):284–8. doi: 10.1016/0002-9343(78)90057-8

PubMed Abstract | CrossRef Full Text | Google Scholar

18. Surks MI, SChadlow AR, Oppenheimer JH. A new radioimmunoassay for plasma L-triiodothyronine: measurements in thyroid disease and in patients maintained on hormonal replacement. J Clin Invest. (1972) 51(12):3104–13. doi: 10.1172/JCI107137

PubMed Abstract | CrossRef Full Text | Google Scholar

19. Van’t Hoff W, Hoffenberg R, London D, Hall R, Joplin G, Besser G, et al. Thyroid extract. Br Med J (1978) 2(6131):200–. doi: 10.1136/bmj.2.6131.200-c

CrossRef Full Text | Google Scholar

20. Singer PA, Cooper DS, Levy EG, Ladenson PW, Braverman LE, Daniels G, et al. Treatment guidelines for patients with hyperthyroidism and hypothyroidism. Standards of Care Committee, American Thyroid Association. Jama (1995) 273(10):808–12. doi: 10.1001/jama.1995.03520340064038

PubMed Abstract | CrossRef Full Text | Google Scholar

21. Wiersinga WM, Duntas L, Fadeyev V, Nygaard B, Vanderpump MP. ETA guidelines: the use of L-T4 + L-T3 in the treatment of hypothyroidism. Eur Thyroid J (2012) 1(2):55–71. doi: 10.1159/000339444

PubMed Abstract | CrossRef Full Text | Google Scholar

22. Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, Mechanick JI, et al. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Endocr Pract (2012) 18(6):988–1028. doi: 10.4158/EP12280.GL

PubMed Abstract | CrossRef Full Text | Google Scholar

23. Okosieme O, Gilbert J, Abraham P, Boelaert K, Dayan C, Gurnell M, et al. Management of primary hypothyroidism: statement by the British Thyroid Association Executive Committee. Clin Endocrinol (Oxf). (2016) 84(6):799–808. doi: 10.1111/cen.12824

PubMed Abstract | CrossRef Full Text | Google Scholar

24. Gkotsina M, Michalaki M, Mamali I, Markantes G, Sakellaropoulos GC, Kalfarentzos F, et al. Improved levothyroxine pharmacokinetics after bariatric surgery. Thyroid (2013) 23(4):414–9. doi: 10.1089/thy.2011.0526

PubMed Abstract | CrossRef Full Text | Google Scholar

25. Pittman CS, Chambers JB Jr., Read VH. The extrathyroidal conversion rate of thyroxine to triiodothyronine in normal man. J Clin Invest. (1971) 50(6):1187–96. doi: 10.1172/JCI106596

PubMed Abstract | CrossRef Full Text | Google Scholar

26. Colucci P, Yue CS, Ducharme M, Benvenga S. A review of the pharmacokinetics of levothyroxine for the treatment of hypothyroidism. Eur Endocrinol (2013) 9(1):40–7. doi: 10.17925/EE.2013.09.01.40

PubMed Abstract | CrossRef Full Text | Google Scholar

27. Ito M, Miyauchi A, Morita S, Kudo T, Nishihara E, Kihara M, et al. TSH-suppressive doses of levothyroxine are required to achieve preoperative native serum triiodothyronine levels in patients who have undergone total thyroidectomy. Eur J Endocrinol (2012) 167(3):373–8. doi: 10.1530/EJE-11-1029

PubMed Abstract | CrossRef Full Text | Google Scholar

28. Gullo D, Latina A, Frasca F, Le Moli R, Pellegriti G, Vigneri R. Levothyroxine monotherapy cannot guarantee euthyroidism in all athyreotic patients. PloS One (2011) 6(8):e22552. doi: 10.1371/journal.pone.0022552

PubMed Abstract | CrossRef Full Text | Google Scholar

29. Peterson SJ, McAninch EA, Bianco AC. Is a normal TSH synonymous with "Euthyroidism" in levothyroxine monotherapy? J Clin Endocrinol Metab (2016) 101(12):4964–73. doi: 10.1210/jc.2016-2660

PubMed Abstract | CrossRef Full Text | Google Scholar

30. Samuels MH, Kolobova I, Smeraglio A, Peters D, Purnell JQ, Schuff KG. Effects of levothyroxine replacement or suppressive therapy on energy expenditure and body composition. Thyroid (2016) 26(3):347–55. doi: 10.1089/thy.2015.0345

PubMed Abstract | CrossRef Full Text | Google Scholar

31. Stock JM, Surks MI, Oppenheimer JH. Replacement dosage of L-thyroxine in hypothyroidism. A re-evaluation. N Engl J Med (1974) 290(10):529–33. doi: 10.1056/NEJM197403072901001

CrossRef Full Text | Google Scholar

32. Penny R, Frasier SD. Elevated serum concentrations of triiodothyronine in hypothyroid patients. Values patients receiving USP Thyroid Am J Dis Child. (1980) 134(1):16–8. doi: 10.1001/archpedi.1980.02130130008003

CrossRef Full Text | Google Scholar

33. Lev-Ran A. Part-of-the-day hypertriiodothyroninemia caused by desiccated thyroid. Jama (1983) 250(20):2790–1. doi: 10.1001/jama.1983.03340200024015

PubMed Abstract | CrossRef Full Text | Google Scholar

34. Nicoloff JT, Low JC, Dussault JH, Fisher DA. Simultaneous measurement of thyroxine and triiodothyronine peripheral turnover kinetics in man. J Clin Invest. (1972) 51(3):473–83. doi: 10.1172/JCI106835

PubMed Abstract | CrossRef Full Text | Google Scholar

35. Wenzel KW, Kirschsieper HE. Aspects of the absorption of oral L-thyroxine in normal man. Metabolism (1977) 26(1):1–8. doi: 10.1016/0026-0495(77)90121-4

PubMed Abstract | CrossRef Full Text | Google Scholar

36. Sherman SI, Malecha SE. Absorption and malabsorption of levothyroxine sodium. Am J Ther (1995) 2(10):814–8. doi: 10.1097/00045391-199510000-00014

PubMed Abstract | CrossRef Full Text | Google Scholar

37. Gatta E, Bambini F, Buoso C, Gava M, Maltese V, Anelli V, et al. Liquid levothyroxine formulations in patients taking drugs interfering with L-T4 absorption. Front Endocrinol (Lausanne). (2022) 13:1080108. doi: 10.3389/fendo.2022.1080108

PubMed Abstract | CrossRef Full Text | Google Scholar

38. Liwanpo L, Hershman JM. Conditions and drugs interfering with thyroxine absorption. Best Pract Res Clin Endocrinol Metab (2009) 23(6):781–92. doi: 10.1016/j.beem.2009.06.006

PubMed Abstract | CrossRef Full Text | Google Scholar

39. Centanni M, Gargano L, Canettieri G, Viceconti N, Franchi A, Delle Fave G, et al. Thyroxine in goiter, Helicobacter pylori infection, and chronic gastritis. N Engl J Med (2006) 354(17):1787–95. doi: 10.1056/NEJMoa043903

PubMed Abstract | CrossRef Full Text | Google Scholar

40. Liu H, Lu M, Hu J, Fu G, Feng Q, Sun S, et al. Medications and food interfering with the bioavailability of levothyroxine: A systematic review. Ther Clin Risk Manage (2023) 19:503–23. doi: 10.2147/TCRM.S414460

CrossRef Full Text | Google Scholar

41. Formenti AM, Daffini L, Pirola I, Gandossi E, Cristiano A, Cappelli C. Liquid levothyroxine and its potential use. Hormones (Athens). (2015) 14(2):183–9. doi: 10.14310/horm.2002.1579

PubMed Abstract | CrossRef Full Text | Google Scholar

42. Yue CS, Scarsi C, Ducharme MP. Pharmacokinetics and potential advantages of a new oral solution of levothyroxine vs. other available dosage forms. Arzneimittelforschung (2012) 62(12):631–6. doi: 10.1055/s-0032-1329951

PubMed Abstract | CrossRef Full Text | Google Scholar

43. Cappelli C, Pirola I, Daffini L, Formenti A, Iacobello C, Cristiano A, et al. A double-blind placebo-controlled trial of liquid thyroxine ingested at breakfast: results of the TICO study. Thyroid (2016) 26(2):197–202. doi: 10.1089/thy.2015.0422

PubMed Abstract | CrossRef Full Text | Google Scholar

44. Cappelli C, Pirola I, Gandossi E, Formenti A, Castellano M. Oral liquid levothyroxine treatment at breakfast: a mistake? Eur J Endocrinol (2014) 170(1):95–9. doi: 10.1530/EJE-13-0693

PubMed Abstract | CrossRef Full Text | Google Scholar

45. Bernareggi A, Grata E, Pinorini MT, Conti A. Oral liquid formulation of levothyroxine is stable in breakfast beverages and may improve thyroid patient compliance. Pharmaceutics. (2013) 5(4):621–33. doi: 10.3390/pharmaceutics5040621

PubMed Abstract | CrossRef Full Text | Google Scholar

46. Guglielmi R, Grimaldi F, Negro R, Frasoldati A, Misischi I, Graziano F, et al. Shift from levothyroxine tablets to liquid formulation at breakfast improves quality of life of hypothyroid patients. Endocr Metab Immune Disord Drug Targets (2018) 18(3):235–40. doi: 10.2174/1871530318666180125155348

PubMed Abstract | CrossRef Full Text | Google Scholar

47. Benvenga S, Capodicasa G, Perelli S, Ferrari SM, Fallahi P, Antonelli A. Increased requirement of replacement doses of levothyroxine caused by liver cirrhosis. Front Endocrinol (Lausanne) (2018) 9:150. doi: 10.3389/fendo.2018.00150

PubMed Abstract | CrossRef Full Text | Google Scholar

48. Pirola I, Daffini L, Gandossi E, Lombardi D, Formenti A, Castellano M, et al. Comparison between liquid and tablet levothyroxine formulations in patients treated through enteral feeding tube. J Endocrinol Invest (2014) 37(6):583–7. doi: 10.1007/s40618-014-0082-9

PubMed Abstract | CrossRef Full Text | Google Scholar

49. Fallahi P, Ferrari SM, Camastra S, Politti U, Ruffilli I, Vita R, et al. TSH normalization in bariatric surgery patients after the switch from L-thyroxine in tablet to an oral liquid formulation. Obes Surg (2017) 27(1):78–82. doi: 10.1007/s11695-016-2247-4

PubMed Abstract | CrossRef Full Text | Google Scholar

50. Fallahi P, Ferrari SM, Marchi S, De Bortoli N, Ruffilli I, Antonelli A. Patients with lactose intolerance absorb liquid levothyroxine better than tablet levothyroxine. Endocrine (2017) 57(1):175–8. doi: 10.1007/s12020-016-1090-7

PubMed Abstract | CrossRef Full Text | Google Scholar

51. Fallahi P, Ferrari SM, Ruffilli I, Antonelli A. Reversible normalisation of serum TSH levels in patients with autoimmune atrophic gastritis who received L-T4 in tablet form after switching to an oral liquid formulation: a case series. BMC Gastroenterol (2016) 16:22. doi: 10.1186/s12876-016-0439-y

PubMed Abstract | CrossRef Full Text | Google Scholar

52. Lobasso A, Nappi L, Barbieri L, Peirce C, Ippolito S, Arpaia D, et al. Severe Hypothyroidism due to the Loss of Therapeutic Efficacy of l-Thyroxine in a Patient with Esophageal Complication Associated with Systemic Sclerosis. Front Endocrinol (Lausanne). (2017) 8:241. doi: 10.3389/fendo.2017.00241

PubMed Abstract | CrossRef Full Text | Google Scholar

53. Reardon DP, Yoo PS. Levothyroxine tablet malabsorption associated with gastroparesis corrected with gelatin capsule formulation. Case Rep Endocrinol (2016) 2016:1316724. doi: 10.1155/2016/1316724

PubMed Abstract | CrossRef Full Text | Google Scholar

54. Ribichini D, Fiorini G, Repaci A, Castelli V, Gatta L, Vaira D, et al. Tablet and oral liquid L-thyroxine formulation in the treatment of naïve hypothyroid patients with Helicobacter pylori infection. Endocrine (2017) 57(3):394–401. doi: 10.1007/s12020-016-1167-3

PubMed Abstract | CrossRef Full Text | Google Scholar

55. Tortora A, La Sala D, Vitale M. Switch from tablet levothyroxine to oral solution resolved reduced absorption by intestinal parasitosis. Endocrinol Diabetes Metab Case Rep (2019) 2019:19–0026. doi: 10.1530/EDM-19-0026

PubMed Abstract | CrossRef Full Text | Google Scholar

56. Saraceno G, Vita R, Trimarchi F, Benvenga S. Interference of L-T4 absorption by proton-pump inhibitors (PPIS) can be solved by a liquid formulation of L-thyroxine (L-T4). Thyroid (2012) 22(s1):a50.

Google Scholar

57. Vita R, Saraceno G, Trimarchi F, Benvenga S. Switching levothyroxine from the tablet to the oral solution formulation corrects the impaired absorption of levothyroxine induced by proton-pump inhibitors. J Clin Endocrinol Metab (2014) 99(12):4481–6. doi: 10.1210/jc.2014-2684

PubMed Abstract | CrossRef Full Text | Google Scholar

58. Benvenga S, Di Bari F, Vita R. Undertreated hypothyroidism due to calcium or iron supplementation corrected by oral liquid levothyroxine. Endocrine (2017) 56(1):138–45. doi: 10.1007/s12020-017-1244-2

PubMed Abstract | CrossRef Full Text | Google Scholar

59. Vita R, Di Bari F, Benvenga S. Oral liquid levothyroxine solves the problem of tablet levothyroxine malabsorption due to concomitant intake of multiple drugs. Expert Opin Drug Delivery (2017) 14(4):467–72. doi: 10.1080/17425247.2017.1290604

CrossRef Full Text | Google Scholar

60. Guglielmi V, Bellia A, Bianchini E, Medea G, Cricelli I, Sbraccia P, et al. Drug interactions in users of tablet vs. oral liquid levothyroxine formulations: a real-world evidence study in primary care. Endocrine (2018) 59(3):585–92. doi: 10.1007/s12020-017-1412-4

PubMed Abstract | CrossRef Full Text | Google Scholar

61. Brancato D, Scorsone A, Saura G, Ferrara L, Di Noto A, Aiello V, et al. Comparison of TSH levels with liquid formulation versus tablet formulations of levothyroxine in the treatment of adult hypothyroidism. Endocr Pract (2014) 20(7):657–62. doi: 10.4158/EP13418.OR

PubMed Abstract | CrossRef Full Text | Google Scholar

62. Vita R, Benvenga S. Tablet levothyroxine (L-T4) malabsorption induced by proton pump inhibitor; a problem that was solved by switching to L-T4 in soft gel capsule. Endocr Pract (2014) 20(3):e38–41. doi: 10.4158/EP13316.CR

PubMed Abstract | CrossRef Full Text | Google Scholar

63. Morini E, Catalano A, Lasco A, Morabito N, Benvenga S. In thyroxine-replaced hypothyroid postmenopausal women under simultaneous calcium supplementation, switch to oral liquid or softgel capsule L-thyroxine ensures lower serum TSH levels and favorable effects on blood pressure, total cholesterolemia and glycemia. Endocrine (2019) 65(3):569–79. doi: 10.1007/s12020-019-01908-x

PubMed Abstract | CrossRef Full Text | Google Scholar

64. Benvenga S. Liquid and softgel capsules of l-thyroxine results lower serum thyrotropin levels more than tablet formulations in hypothyroid patients. J Clin Transl Endocrinol (2019) 18:100204. doi: 10.1016/j.jcte.2019.100204

PubMed Abstract | CrossRef Full Text | Google Scholar

65. Antonelli A, Elia G, Ragusa F, Paparo SR, Cavallini G, Benvenga S, et al. The stability of TSH, and thyroid hormones, in patients treated with tablet, or liquid levo-thyroxine. Front Endocrinol (Lausanne) (2021) 12:633587. doi: 10.3389/fendo.2021.633587

PubMed Abstract | CrossRef Full Text | Google Scholar

66. Cappelli C, Pirola I, Daffini L, Gandossi E, Agosti B, Castellano M. Thyroid hormonal profile in elderly patients treated with two different levothyroxine formulations: A single institute survey. Eur Geriatric Med (2014) 5(6):382–5. doi: 10.1016/j.eurger.2014.09.006

CrossRef Full Text | Google Scholar

67. Parle JV, Franklyn JA, Cross KW, Jones SR, Sheppard MC. Thyroxine prescription in the community: serum thyroid stimulating hormone level assays as an indicator of undertreatment or overtreatment. Br J Gen Pract (1993) 43(368):107–9.

PubMed Abstract | Google Scholar

68. Canaris GJ, Manowitz NR, Mayor G, Ridgway EC. The Colorado thyroid disease prevalence study. Arch Intern Med (2000) 160(4):526–34. doi: 10.1001/archinte.160.4.526

PubMed Abstract | CrossRef Full Text | Google Scholar

69. Flynn RW, Bonellie SR, Jung RT, MacDonald TM, Morris AD, Leese GP. Serum thyroid-stimulating hormone concentration and morbidity from cardiovascular disease and fractures in patients on long-term thyroxine therapy. J Clin Endocrinol Metab (2010) 95(1):186–93. doi: 10.1210/jc.2009-1625

PubMed Abstract | CrossRef Full Text | Google Scholar

70. Sawin CT, Geller A, Wolf PA, Belanger AJ, Baker E, Bacharach P, et al. Low serum thyrotropin concentrations as a risk factor for atrial fibrillation in older persons. N Engl J Med (1994) 331(19):1249–52. doi: 10.1056/NEJM199411103311901

PubMed Abstract | CrossRef Full Text | Google Scholar

71. Bauer DC, Ettinger B, Nevitt MC, Stone KL. Risk for fracture in women with low serum levels of thyroid-stimulating hormone. Ann Intern Med (2001) 134(7):561–8. doi: 10.7326/0003-4819-134-7-200104030-00009

PubMed Abstract | CrossRef Full Text | Google Scholar

72. Rodondi N, Newman AB, Vittinghoff E, de Rekeneire N, Satterfield S, Harris TB, et al. Subclinical hypothyroidism and the risk of heart failure, other cardiovascular events, and death. Arch Intern Med (2005) 165(21):2460–6. doi: 10.1001/archinte.165.21.2460

PubMed Abstract | CrossRef Full Text | Google Scholar

73. Cappola AR, Ladenson PW. Hypothyroidism and atherosclerosis. J Clin Endocrinol Metab (2003) 88(6):2438–44. doi: 10.1210/jc.2003-030398

PubMed Abstract | CrossRef Full Text | Google Scholar

74. Danese MD, Ladenson PW, Meinert CL, Powe NR. Clinical review 115: effect of thyroxine therapy on serum lipoproteins in patients with mild thyroid failure: a quantitative review of the literature. J Clin Endocrinol Metab (2000) 85(9):2993–3001. doi: 10.1210/jcem.85.9.6841

PubMed Abstract | CrossRef Full Text | Google Scholar

75. Ribba B, Peck R, Hutchinson L, Bousnina I, Motti D. Digital therapeutics as a new therapeutic modality: A review from the perspective of clinical pharmacology. Clin Pharmacol Ther (2023) 114(3):578–90. doi: 10.1002/cpt.2989

PubMed Abstract | CrossRef Full Text | Google Scholar

76. DTx product best practices fact Sheet. Digital Therapeutics Alliance (2019). Available at: https://dtxalliance.org/wp-content/uploads/2021/01/DTA_DTx-Product-Best-Practices_11.11.19.pdf.

Google Scholar

78. How digital therapy benefits patients, providers, and the health ecosystem. International Business Machines Corporation (2019). Available at: https://www.ibm.com/downloads/cas/DO1REYRX.

Google Scholar

79. Improving access to digital therapeutics in Europe European Federation of Pharmaceutical Manufacturers & Associations (2023). Available at: https://efpia.eu/media/677347/improving-access-to-digital-therapeutics-in-europe.pdf.

Google Scholar

80. Sadée W, Dai Z. Pharmacogenetics/genomics and personalized medicine. Hum Mol Genet (2005) 14:R207–14. doi: 10.1093/hmg/ddi261

PubMed Abstract | CrossRef Full Text | Google Scholar

81. Mathur S, Sutton J. Personalized medicine could transform healthcare. BioMed Rep (2017) 7(1):3–5. doi: 10.3892/br.2017.922

PubMed Abstract | CrossRef Full Text | Google Scholar

82. Kaplon H, Muralidharan M, Schneider Z, Reichert JM. Antibodies to watch in 2020. MAbs (2020) 12(1):1703531. doi: 10.1080/19420862.2019.1703531

PubMed Abstract | CrossRef Full Text | Google Scholar

83. Schmid P, Rugo HS, Adams S, Schneeweiss A, Barrios CH, Iwata H, et al. Atezolizumab plus nab-paclitaxel as first-line treatment for unresectable, locally advanced or metastatic triple-negative breast cancer (IMpassion130): updated efficacy results from a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet Oncol (2020) 21(1):44–59. doi: 10.1016/S1470-2045(19)30689-8

PubMed Abstract | CrossRef Full Text | Google Scholar

84. Falzone L, Salomone S, Libra M. Evolution of Cancer pharmacological treatments at the turn of the third millennium. Front Pharmacol (2018) 9:1300. doi: 10.3389/fphar.2018.01300

PubMed Abstract | CrossRef Full Text | Google Scholar

85. Dummer R, Queirolo P, Gerard Duhard P, Hu Y, Wang D, de Azevedo SJ, et al. Atezolizumab, vemurafenib, and cobimetinib in patients with melanoma with CNS metastases (TRICOTEL): a multicentre, open-label, single-arm, phase 2 study. Lancet Oncol (2023) 23(9):1145–55. doi: 10.1016/S1470-2045(23)00334-0

CrossRef Full Text | Google Scholar

86. Kim J, Oh J, Son D, Kwon H, Astillo PV, You I. APSec1.0: innovative security protocol design with formal security analysis for the artificial pancreas system. Sensors (Basel) (2023) 23(12):5501. doi: 10.3390/s23125501

PubMed Abstract | CrossRef Full Text | Google Scholar

87. Allen N, Gupta A. Current diabetes technology: striving for the artificial pancreas. Diagnostics (Basel) (2019) 9(1):31. doi: 10.3390/diagnostics9010031

PubMed Abstract | CrossRef Full Text | Google Scholar

88. Abraham MB, Nicholas JA, Smith GJ, Fairchild JM, King BR, Ambler GR, et al. Reduction in hypoglycemia with the predictive low-glucose management system: A long-term randomized controlled trial in adolescents with type 1 diabetes. Diabetes Care (2018) 41(2):303–10. doi: 10.2337/dc17-1604

PubMed Abstract | CrossRef Full Text | Google Scholar

89. Weissberg-Benchell J, Antisdel-Lomaglio J, Seshadri R. Insulin pump therapy: a meta-analysis. Diabetes Care (2003) 26(4):1079–87. doi: 10.2337/diacare.26.4.1079

PubMed Abstract | CrossRef Full Text | Google Scholar

90. Steineck I, Cederholm J, Eliasson B, Rawshani A, Eeg-Olofsson K, Svensson AM, et al. Insulin pump therapy, multiple daily injections, and cardiovascular mortality in 18,168 people with type 1 diabetes: observational study. Bmj (2015) 350:h3234. doi: 10.1136/bmj.h3234

PubMed Abstract | CrossRef Full Text | Google Scholar

91. Pease A, Zomer E, Liew D, Lo C, Earnest A, Zoungas S. Cost-effectiveness of health technologies in adults with type 1 diabetes: a systematic review and narrative synthesis. Syst Rev (2020) 9(1):171. doi: 10.1186/s13643-020-01373-y

PubMed Abstract | CrossRef Full Text | Google Scholar

92. Guglielmi R, Frasoldati A, Zini M, Grimaldi F, Gharib H, Garber JR, et al. Italian association of clinical endocrinologists statement-replacement therapy for primary hypothyroidism: a brief guide for clinical practice. Endocr Pract (2016) 22(11):1319–26. doi: 10.4158/EP161308.OR

PubMed Abstract | CrossRef Full Text | Google Scholar

93. Ventola CL. The antibiotic resistance crisis: part 1: causes and threats. P&T: Peer-reviewed J Formul Manag (2015) 40(4):277–83.

Google Scholar

94. Ventola CL. The antibiotic resistance crisis: part 2: management strategies and new agents. P&T: Peer-reviewed J Formul Manag (2015) 40(5):344–52.

Google Scholar

95. Moser C, Lerche CJ, Thomsen K, Hartvig T, Schierbeck J, Jensen P, et al. Antibiotic therapy as personalized medicine - general considerations and complicating factors. Apmis (2019) 127(5):361–71. doi: 10.1111/apm.12951

PubMed Abstract | CrossRef Full Text | Google Scholar

Keywords: tailored pharmaceuticals, precision pharmaceuticals, personalized drug formulations, targeted drug delivery, levothyroxine, hypothyroidism treatment, L-T4 personalized treatment

Citation: Cappelli C, Gatta E and Ippolito S (2024) Levothyroxine personalized treatment: is it still a dream? Front. Endocrinol. 14:1334292. doi: 10.3389/fendo.2023.1334292

Received: 06 November 2023; Accepted: 18 December 2023;
Published: 08 January 2024.

Edited by:

Alessandro Antonelli, University of Pisa, Italy

Reviewed by:

Eugenia Balestri, University of Pisa, Italy
Francesca Ragusa, University of Pisa, Italy

Copyright © 2024 Cappelli, Gatta and Ippolito. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Carlo Cappelli, carlo.cappelli@unibs.it

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.