Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Comment on “Levothyrox® New and Old Formulations: Are they Switchable for Millions of Patients?”

This is a preview of subscription content, log in to check access.


  1. 1.

    Concordet D, Gandia P, Montastruc JL, Bousquet-Melou A, Lees P, Ferran A, et al. Levothyrox® new and old formulations: are they switchable for millions of patients? Clin Pharmacokinet. 2019;58(7):827–33.

  2. 2.

    Food and Drug Administration. Guidance for industry: Average, population, and individual approaches to establishing bioequivalence. Rockville: U.S. Department of Health and Human Services, Center for Drug Evaluation and Research (CDER); 1999.

  3. 3.

    Food and Drug Administration. In vivo bioequivalence studies based on population and individual bioequivalence approaches. Rockville: U.S. Department of Health and Human Services FDA, Center for Drug Evaluation and Research (CDER); 1997.

  4. 4.

    Chow S-C. Individual bioequivalence-a review of FDA draft guidance. Drug Inf J. 1999;33(2):435–44.

  5. 5.

    Hsuan FC. Some statistical considerations on the FDA draft guidance for individual bioequivalence. Stat Med. 2000;19(20):2879–84.

  6. 6.

    Endrenyi L, Taback N, Tothfalusi L. Properties of the estimated variance component for subject-by-formulation interaction in studies of individual bioequivalence. Stat Med. 2000;19(20):2867–78.

  7. 7.

    Yu Y, Teerenstra S, Neef C, Burger D, Maliepaard M. A comparison of the intrasubject variation in drug exposure between generic and brand-name drugs: a retrospective analysis of replicate design trials. Br J Clin Pharmacol. 2016;81(4):667–78.

  8. 8.

    Maliepaard M, Hekster YA, Kappelle A, van Puijenbroek EP, Elferink AJ, Welink J, et al. Requirements for generic anti-epileptic medicines: a regulatory perspective. J Neurol. 2009;256(12):1966–71.

  9. 9.

    Cristofoletti R, Rowland M, Lesko LJ, Blume H, Rostami-Hodjegan A, Dressman JB. Past, present, and future of bioequivalence: improving assessment and extrapolation of therapeutic equivalence for oral drug products. J Pharm Sci. 2018;107(10):2519–30.

  10. 10.

    Faasse K, Cundy T, Petrie KJ. Medicine and the media. Thyroxine: anatomy of a health scare. BMJ. 2009;339:b5613.

  11. 11.

    Saravanan P, Chau WF, Roberts N, Vedhara K, Greenwood R, Dayan CM. Psychological well-being in patients on “adequate” doses of L-thyroxine: results of a large, controlled community-based questionnaire study. Clin Endocrinol (Oxf). 2002;57:577–85.

Download references

Author information

Correspondence to Yang Yu.

Ethics declarations


No external funding was used in the preparation of this manuscript.

Conflict of interest

Yang Yu and Marc Maliepaard declare that they have no potential conflicts of interest that might be relevant to the contents of this manuscript.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Yu, Y., Maliepaard, M. Comment on “Levothyrox® New and Old Formulations: Are they Switchable for Millions of Patients?”. Clin Pharmacokinet 59, 281–282 (2020).

Download citation