70 Years of Levothyroxine.

• Author: Kahaly, George J.
• Place / Publishing House: Cham : : Springer International Publishing AG,, 2021.; ©2021.
• Year of Publication: 2021
• Edition: 1st ed.
• Language: English
• Physical Description: 1 online resource (141 pages)

Table of Contents

Intro -- Preface -- Contents -- About the Editor and Contributors -- Editor -- Contributors -- Therapeutic Use of Levothyroxine: A Historical Perspective -- 1 Introduction -- 2 Early Beginnings: Growing Understanding of the Thyroid -- 2.1 Cretinism, Goitre, and the Recognition of the Importance of the Thyroid Gland -- 2.2 An Endocrine Function for the Thyroid Gland -- 3 Towards the Modern Era in the Management of Hypothyroidism -- 3.1 Introduction of Chemically Synthesised Thyroid Hormones -- 3.2 Monotherapy or Combination Therapy? -- 3.3 Technological Advances: Better Assays of Thyroid Function -- 3.4 Recent Developments in Levothyroxine Therapy -- 4 Where We Stand Today -- 4.1 A Fuller (But Incomplete) Understanding of Thyroid Hormone Homeostasis -- 4.2 Unresolved Issues and Current Research Questions -- 5 Conclusions -- References -- Administration and Pharmacokinetics of Levothyroxine -- 1 Introduction -- 2 Absorption, Distribution, Metabolism, and Elimination of Levothyroxine -- 2.1 Absorption and Distribution -- 2.2 Metabolism and Elimination -- 3 Factors That May Alter Exposure to an Oral Dose of Levothyroxine -- 3.1 Factors That May Reduce Exposure to Levothyroxine -- 3.1.1 Diurnal Variation -- 3.1.2 Malabsorption of, and Suboptimal Adherence to, Levothyroxine -- 3.2 Factors That May Alter the Measured Level of Thyrotropin -- 4 Levothyroxine Tablets in a Changing Regulatory Environment -- 5 Conclusions -- References -- Pharmacodynamic and Therapeutic Actions of Levothyroxine -- 1 Introduction -- 2 Thyroid Hormone Homeostasis -- 2.1 Conversion of T4 to T3 -- 2.2 Regulation of Deiodinases and Individual "Set Points" for Thyroid Function -- 2.3 Thyroid Hormone Receptors (THRs) -- 2.4 Regulation of TSH Release -- 3 Clinical Pharmacodynamics of (Levo)Thyroxine -- 3.1 Which Thyroid Hormones Are Important? -- 3.2 Actions on Skeletal Muscle.

3.2.1 Mechanisms -- 3.2.2 Clinical Studies of Interest -- 3.3 Effects on Lipid Profiles -- 3.4 Actions in Adipose Tissue -- 3.5 Effects on Glucose Metabolism -- 3.6 Actions on Mood and Affect -- 3.7 Fatigue -- 3.8 Actions on Inflammation and Haemostasis -- 3.9 Effects in the Kidney -- 3.10 Effects on the Heart and in Bone -- 4 Evidence-Based Guidelines for the Management of Hypothyroidism -- 4.1 Current Status of Evidence-Based Guidelines -- 4.2 Levothyroxine Monotherapy, or Levothyroxine Plus Triiodothyronine, for Hypothyroidism -- 4.3 Barriers to Optimal Care of Patients with Hypothyroidism -- 4.3.1 The Impact of the Diagnosis Itself -- 4.3.2 Avoiding over Diagnosis -- 5 Conclusions -- References -- Levothyroxine in Pregnancy -- 1 Introduction -- 2 Changes in Thyroid Function During Pregnancy -- 3 Maternal and Foetal Outcomes in Women with Hypothyroidism -- 3.1 Effects of Hypothyroidism on Fertility and Preterm Delivery -- 3.2 LT4 Treatment and Pregnancy Outcomes: Importance of Thyroid Autoimmunity -- 3.3 LT4 Treatment of Euthyroid Women with Thyroid Autoimmunity -- 3.4 Thyroid Autoimmunity and Pregnancy Outcomes in Women Receiving Assisted Reproduction Technologies (ART) -- 3.5 Effects on Offspring -- 4 Summary of Current Major Guidelines -- 4.1 Guidelines Considered Here -- 4.2 Overt Hypothyroidism During Pregnancy and Postpartum -- 4.3 Subclinical Hypothyroidism During Pregnancy and Postpartum -- 5 Conclusions -- References -- Levothyroxine in Children -- 1 Introduction -- 2 Overview of Hypothyroidism in Children -- 2.1 Congenital Hypothyroidism -- 2.2 Subclinical Hypothyroidism -- 2.2.1 Prevalence and Clinical Course -- 2.2.2 Outcomes in Children with Subclinical Hypothyroidism -- 2.3 Other Causes of Hypothyroidism in Children -- 3 Effects of Levothyroxine in Children with Hypothyroidism -- 3.1 Congenital or Overt Hypothyroidism.

3.2 Subclinical Hypothyroidism -- 3.3 Biochemically Euthyroid Children -- 4 Conclusions -- References -- Levothyroxine in the Older Patient -- 1 Thyroid Homeostasis in Older Individuals -- 1.1 Thyroid Homeostasis -- 1.2 Thyroid Hormone Levels and Clinical Outcomes -- 2 Therapeutic Use of Levothyroxine in Older Patients with Hypothyroidism -- 2.1 Analyses from Randomised, Placebo-Controlled Trials -- 2.2 Observational Studies of Levothyroxine in Older Patients with Hypothyroidism -- 2.3 Managing Elderly Patients with Hypothyroidism: Implications of the SORTED 1 Trial -- 3 Conclusions -- References -- Levothyroxine and the Heart -- 1 Introduction -- 2 Overview of the Adverse Effects of Thyroid Dysfunction on the Heart -- 3 Effects of Levothyroxine Replacement Therapy on the Cardiovascular System -- 3.1 Effects on ECG Parameters -- 3.2 Effects of l-Thyroxine on Cardiovascular Structure and Function -- 3.3 Effects of LT4 on Major Adverse Cardiovascular Events -- 3.4 Effects of LT4 in Patients with Heart Failure -- 4 Conclusions -- References -- Levothyroxine and Bone -- 1 Overview of the Effects of Thyroid Hormones on the Skeleton -- 2 Bone Health in Patients Receiving Treatment with Levothyroxine -- 2.1 Patients with Congenital Hypothyroidism -- 2.2 Adult Patients with Hypothyroidism -- 2.2.1 Subclinical Hypothyroidism -- 2.2.2 Overt Hypothyroidism -- 2.3 Effects of Thyrotropin-Suppressive Doses of Levothyroxine -- 3 Clinical Perspectives -- References -- Levothyroxine and Cancer -- 1 Introduction -- 1.1 Overview of the Management of Differentiated Thyroid Cancer -- 1.2 Scope of This Chapter -- 2 Application of Thyrotropin-Suppressive Doses of Levothyroxine After Surgery and Radioactive Iodine for Well-Differentiated Thyroid Tumours -- 2.1 Need for Suppression of Thyrotropin in Thyroid Cancer Survivors.

2.2 Long-Term Consequences of Thyroidectomy and Thyrotropin Suppression -- 2.2.1 Bone -- 2.2.2 The Cardiovascular System -- 2.2.3 Patient-Reported Outcomes -- 3 Thyroid Hormones and Cancer Risk -- 4 Conclusions -- References -- Practical Application of Levothyroxine-Based Therapy -- 1 Introduction -- 2 Safety and Tolerability of Levothyroxine -- 2.1 Avoiding Symptoms of Thyroid Dysfunction -- 2.2 Adverse Reactions to the LT4 Tablet Itself -- 3 How to Prescribe and Take Levothyroxine -- 4 Overview of Guidelines on the Management of Hypothyroidism -- 5 Conclusions -- References.