Derrica Hawkins 2014 PharmD Candidate Clinical and Research Seminar II Dr. Charlie Colquitt

 Prevalence  Background  Define thyroid disease  Causes of thyroid disease  Clinical Presentation  Treatment options

 20 million Americans have some form of thyroid disease  Women are five to eight times more likely than men to have thyroid problems  60 percent of those with thyroid disease are unaware of their condition  Older cats often get hyperthyroidism more often than dogs

 Butterfly shaped organ in the front of the neck  Below the larynx (voice box)  One on each side of the windpipe, connected by the isthmus  Two types of cells: follicular cells and parafollicular cells  Follicular cells, which secrete iodine-containing hormones called thyroxine (T4) and triiodothyronine (T3)  Parafollicular cells secrete the hormone calcitonin

Hyperthyroidism Hypothyroidism ◦ antibody-mediated auto- immune reaction, but the trigger for this reaction is still unknown ◦ deficiency of thyroid hormones and is manifested largely by a reversible slowing down of all body functions

 Graves Disease  Pituitary adenoma  Excessive doses of thyroid hormone  Thyroiditis  Iodide  Amiodarone  Interferon

 Autoimmune disorder  Eight times more common in women than men Signs: o Exophthalmos o Pretibial myxedema o Thyroid enlargement

 Nervousness  Anxiety  Increased perspiration  Heat intolerance  Hyperactivity  Palpitations

 Low TSH concentration o Normal range microIU/mL  Elevated free and total T3 and T4 concentrations o Normal range mcg/dL  Elevated radioactive iodine uptake (RAIU) by the thyroid gland  Thyroid stimulating antibodies (TSAb)  Thyroid biopsy

 Thyroidectomy o Large thyroid gland(>80 g) o Severe ophthalmopathy o Lack of remission on antithyroid drug treatment Most common complication is hypothyroidism

DrugMOADoseContraindicatio ns/ Side Effect Monitoring Parameters/ Notes Propylthiouracil (PTU) Methimazole (tapazole) Inhibit oxidation of iodine in the thyroid gland. PTU inhibits the peripheral conversion of T4 to T3 50 mg TID until euthyroid 5-15 mg daily (10X more potent than PTU) Headache, rash, itching, constipation BBW(PTU) - Liver damage and acute liver failure CBC, LFT’s, thyroid function test every 4-6 weeks / Patients – abdominal pain, yellow skin/eyes, dark urine Potassium Iodide and iodine solution (lugol’s solution) Saturated solution of potassium iodide (SSKI) Inhibit thyroid hormone biosynthesis by interfering with intrathyroidal iodide use 4-8drops Q8H 4-5 drops Q8H Rash, metallic taste, sore throat, GI upset Thyroid function test / Take with food Radioactive Iodine sodium iodide 131 (131I) RAI disrupts hormone synthesis by incorporating into thyroid hormones and thyroglobulin 5 to 15 mCi Pregnancy/ Nausea/vomiting, dry mouth

 Rare life-threatening medical emergency

Signs and Symptoms Treatment  High fever (>39.4°C [103°F]),  Tachycardia(>140 BPM)  Dehydration  Delirium  Nausea/vomiting  Coma  Propylthiouracil 900–1200 mg/day PO Q4-6H +  Lugol solution 5–10 drops PO Q8H or SSKI 3-5 drops PO Q8H +  Propranolol 40–80 mg PO Q6H +  Dexamethasone 2-4 mg/day orally or IV Q6H +  Supportive therapy(fluids etc

 Hashimoto’s disease  Iatrogenic hypothyroidism  Iodine deficiency  Thyroid hypoplasia  Thyroidectomy  Pituitary disease  Hypothalamic disease

 Dry skin  Cold intolerance  Weight gain  Constipation  Weakness  Depression  Loss of ambition and energy

 Elevated TSH concentration o Normal range microIU/mL  Low free and/or total T4 and T3 concentration o Normal range mcg/dL

DrugDoseMOAContraindica tion/ Side Effect Monitoring Parameters/ Notes Levothyroxine T4 (Synthroid, Levothroid, Levoxyl ) 50–60 mcg mg/day in elderly and patients with cardiac disease Synthetic thyroid hormone that increases cellular metabolism and plays an important role in growth Acute MI, thyrotoxicosis, Uncorrected renal insufficiency/ Euthyroid- no side effect Hyperthroid- palpitations, sweating, weight loss BBW-Should not be used either alone or with other therapeutic agents for the treatment of obesity or weight loss. Check TSH and cinical symptoms every 6-8 weeks/ Empty stomach, 30 minutes before breakfast, with a full glass of water Liothyronine(T3, Cytomel, Triostat) mcg/daySame as above Dessicated thyroid(Armour Thyroid) mg orally/day; increase by 15 mg every weeks Dose in grains Same as above Not safe and effective (FDA)

 Brown S, Shapiro K. RxPrep Course Book edition.  Dipiro J, Talbert B, Yee GC, Matzke GR, Wells BG, Posey LM (eds.). Pharmacotherapy: A Pathophysiologic Approach, 7th edition, New York, McGraw-Hill,  Micromedex. Accessed October 1, 2013.