The modern and future management of hypothyroidism

Hypothyroidism presents a unique challenge in many ways, both to patients with the condition, and to healthcare systems that care for them. For example, it is one of the most common non-communicable diseases. While the prevalence of hypothyroidism increases with age, many people worldwide develop the condition at a younger age, including women of childbearing potential. Levothyroxine (LT4), the gold standard for the pharmacologic management of hypothyroidism, appears regularly within the top few most-prescribed medications in any given country.

However, these statistics alone do not give the full picture of the burden of hypothyroidism. Unmet medical needs persist in its management. For decades, physicians have understood the principle of adjusting the dose of LT4 based on the circulating level of thyrotropin. Nevertheless, careful optimisation of the LT4 dose does not resolve symptoms of hypothyroidism and fully correct the associated dysregulation of cardiovascular factors in a substantial minority of patients. We have strong evidence that hypothyroidism reduces the chances of a woman conceiving a child, and even if she does so it reduces the chances of a successful pregnancy outcome.

Two complementary strategies are available for addressing the burden of hypothyroidism: refining the existing LT4 treatment and seeking additional treatments for those for whom this will not be enough. The development of novel formulations of LT4, with tightened specifications for dosing accuracy, stability and bioequivalence between dosage strengths will help to address the current management of hypothyroidism. In the future, new thinking, new data and new clinical trials are breathing life into research on the role of triiodothyronine (liothyronine, LT3) in thyroid care.

This book combines a distinguished panel of international expert physicians and clinical researchers to explore these important issues. Professor Leonidas H Duntas lays out the therapeutic rationale for developing a new LT4 with tightened specification for the modern era of hypothyroidism management, and Professor George J Kahaly describes in detail the pharmacokinetics of a modern LT4 preparation. Professors Salman Razvi and Gabriela Brenta review its potential for the management of hypothyroidism, including overt and (always controversial) subclinical presentations. Professors Zhongyan Shan and Kris G Poppe summarise the latest research on the adverse impact of hypothyroidism on fertility and pregnancy outcomes. Drs Ulrike Gottwald-Hostalek and Yorki Tayrouz summarise the implications for safety and tolerability of a modern, re-engineered LT4 preparation. Finally, Professor Antonio C Bianco reviews the current and (and increasingly bright) future prospects for administration of LT3 alongside optimised LT4 in the management of selected patients with hypothyroidism, a field that has long been paralysed by the negative results of inappropriately designed clinical trials.

We believe that our book brings together the latest thinking and research on the key aspects of hypothyroidism and its modern management. We hope you find it of interest and useful in your clinical practice.

Gabriela Brenta
Dr. Cesar Milstein Hospital, Buenos Aires, Argentina

Ulrike Gottwald-Hostalek
Merck Healthcare KGaA, Darmstadt, Germany