Thyroid Disorders Self-Study 2024

2/1/2024 Introduction to Thyroid Disorders Self-Study Devada Singh-Franco, PharmD, CDCES Associate Professor, Pharmacy Practice [email protected] 1 Guidance on material for exam  All slides are for your information/reference…except for slides with   Please study the information on the slides with ...

2/1/2024 Introduction to Thyroid Disorders Self-Study Devada Singh-Franco, PharmD, CDCES Associate Professor, Pharmacy Practice [email protected] 1 Guidance on material for exam  All slides are for your information/reference…except for slides with   Please study the information on the slides with   Please go through all slides to see which ones have  Please only know generic names, as only generic names of drugs will be on the exam  Please know how to dose levothyroxine **For online assignments/quizzes, please review/use ALL slides** 2 1 2/1/2024 Objectives 1. Describe signs/symptoms of hyper- and hypothyroidism. 2. Outline changes seen in thyroid function tests. 3. Describe mode of action, patient selection, initial, maintenance and maximal doses, drug interactions, and adverse effects for thionamides, beta blockers, and iodides. 4. Compare and contrast products available for thyroid supplementation in hypothyroidism; describe drug of choice. 5. Outline starting and maintenance doses and adverse effects for levothyroxine and monitoring of therapy. 6. Provide goals for treating thyroid disorders, including TSH and FT4 values. 7. Construct rational therapeutic regimens for treatment of thyroid disorders for all patients, including pregnant women. 8. Provide monitoring parameters and frequency of monitoring for patients treated for thyroid disorders. 3 Thyroid gland  An endocrine gland that uses iodine to create thyroid hormones  Located in the middle of the neck  Releases thyroid hormones (THs) that regulate the body's physiological functions https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/thyroid-glanddisorders/overview-of-the-thyroid-gland 4 2 2/1/2024 1. Hypothalamus detects when circulating THs are low and will release TRH (Brain) 2. TRH instructs pituitary to release TSH (Brain) 3. TSH instructs thyroid gland to secrete THs (Neck) Arbl.cvmbs.colostate.edu/…/control.html 5 TSH: Thyroid Stimulating Hormone  Elevated levels in primary hypothyroidism  Hypothalamus will detect persistently low levels of thyroid hormones and secrete TRH (thyrotropin-releasing hormone) which will instruct pituitary to secrete TSH (which will unsuccessfully try to stimulate thyroid gland to secrete thyroid hormones)   Low levels in hyperthyroidism  Hypothalamus will detect persistently elevated levels of thyroid hormones and no longer secrete TRH and so pituitary gland will not receive instructions to secrete TSH.  Thyroid gland is functioning independently to secrete THs 6 3 2/1/2024 T4 (Thyroxine) & T3 (Triiodothyronine)  Thyroid gland (TG) will secrete greater amounts of T4 than T3 into circulation  T4 is solely produced by the TG; it is significantly less biologically active than T3  T3 is more biologically active than T4  99% protein-bound and binds more tightly to proteins than T3)  T3 has a T1/2 of 1 day (>99% protein-bound but binds less tightly to proteins) 7 T4 (Thyroxine) & T3 (Triiodothyronine) Only free (unbound) T3 & T4 will diffuse into cells Thyroid hormones will bind to thyroid hormone receptors within cells T3 has a greater affinity for thyroid hormone receptors than T4 therefore T3 has greater potency than T4 to carry out metabolic function described in the next slide 8 4 2/1/2024 T4 (Thyroxine) & T3 (Triiodothyronine)  Biological effects of thyroid hormones:  oxygen consumption by most tissues   basal metabolic rate  Respiration  Brain development  Menstrual cycle/Fertility  Body temperature  Sleep  Skin maintenance  Bone development  Cardiac function  Muscle strength  GI function  Lipid, protein and carbohydrate homeostasis 9 Thyroid Function Tests (TFTs) FT4 (ng/dL) Normal 0.8-2.7 TSH (mIU/L) 0.5-4.7 Hyper   Hypo    FT4= Free T4 TSH= Thyroid stimulating hormone 10 5 2/1/2024  Calculate the IBW Females 45.5 Kg + 2.3 Kg for every inch over 5 feet Males 50 Kg + 2.3 Kg for every inch over 5 feet What is the IBW for a patient who is 5’8”? 11 Calculate the IBW Females 45.5 Kg + 2.3 Kg for every inch over 5 feet Males 50 Kg + 2.3 Kg for every inch over 5 feet What is the IBW for a patient who is 5’8”? Female: 63.9 or 64 Kg Male: 68.4 Kg 12 6 2/1/2024 Selected References 1.Kane MP, Bakst G. Thyroid Disorders. In: DiPiro JT, Yee GC, Haines ST, Nolin TD, Ellingrod VL, Posey L. eds. DiPiro’s Pharmacotherapy: A Pathophysiologic Approach, 12e. McGraw Hill; 2023. https://accesspharmacy-mhmedicalcom. 2.Thyroid Gland. In: Molina PE. eds. Endocrine Physiology, 5e. McGraw Hill; 2018. https://accessmedicine-mhmedicalcom. 13 7