Thyroid Disorders- Chapter 25 Flashcards
Thyroid Hormones
- The thyroid gland secretes hormones that have an affect on nearly all cells in the body
- They regulate growth and metabolism
Risk Factors for Thyroid Disease
- Gender
- Age
- Pregnancy
- Diabetes
- Cigarette smoking
Diagnostic Tests for Thyroid Disease
- TSH test
- T4 test
- Thyroid antibody test
- Radioactive iodine uptake
TSH Test
-A low TSH level signals hyperthyroidism
T4 Test
- High levels of T4 signal hyperthyroidism
- Low levels signal hypothyroidism
Thyroid Antibody Test
-If thyroid antibodies are present, autoimmune thyroid disease is diagnosed
Radioactive Iodine Uptake (RAIU)
- A low dose of radioactive iodine is administered
- RAIU is high in hyperthyroidism and low in hypothyroidism
What Causes Hyperthyroidism?
- Thyroid tumors
- Inflammation of the thyroid gland
- Grave’s disease
Grave’s Disease
- An autoimmune disease
- The body generates thyroid stimulating antibodies (TSA’s)
- TSA’s bind to receptors on the thyroid gland and mimic TSH
- Thyroid gland releases T3 and T4, but there is no negative feedback
Symptoms of Hyperthyroidism
- Palpitations
- Rapid heart rate
- Muscle weakness
- Tremor
- Weight loss
- Shortness of breath
- Enlarged thyroid
- Bulging eyes
- Sweating
- Flushing
- etc.
Treatment of Hyperthyroidism
- Radioactive iodine
- Antithyroid drugs
- Surgery
Antithyroid Drugs (Thioamides)
- propylthyiouracil (PTU) and methimazole block the synthesis of T3 and T4
- They bind thyroid peroxidase so no new thyroid hormone is formed
- PTU also blocks the conversion of T4 to T3
Thioamides Examples
- methimazole
- propylthiouracil
Generic: methimazole
Tapazole
-For hyperthyroidism
Generic: propylthiouracil
Propyl-Thyracil
-For hyperthyroidism
Thioamides ADR’s
- Sore throat and hoarseness
- Goiter
- Redness or itching
- Hepatitis
- Arthritis
- Unusual bleeding, bruising, etc.
Thioamides Warning Labels
- TAKE ON EMPTY STOMACH OR WITH FOOD BUT ALWAYS TAKE IT THE SAME WAY
- AVOID PREGNANCY
Hypothyroidism
-Thyroid glands secrete deficient amounts of thyroid hormones
Symptoms of Hypothyroidism
- Slowed heart rate
- Lethargy
- Hypertension
- Enlarged heart
- Dry, course hair
- Deep hoarse voice
- Slow speech, thick tongue
- Cold intolerance
- Facial swelling
Treatment of Hypothyroidism
- Thyroid hormone replacement
- Most prescribed treatment is synthetic T4
Hypothyroidism Drugs Examples
- levothyroxine (T4)
- liothyronine (T3)
- dessicated thyroid
Generic: levothyroxine
Eltroxin
Synthroid
-For hypothyroidism
Generic: liothyronine
Cytomel
-For hypothyroidism
Generic: dessicated thyroid
Thyroid
-For hypothyroidism
Liothyronine Vs. Levothyroxine
Liothyronine
- T3
- Rapid onset
- Short duration
- Half-life up to 24 hours
- 3-4 x more potent
- Administered in divided doses
Levothyroxine
- Synthetic T4
- Longer onset
- Longer duration
- Half-life greater than 7 days
- Less potent
- Once daily dosing
Hypothyroidism Drugs ADR’s
- With incorrect dose, same symptoms as hypothyroidism and hyperthyroidism
- Can affect blood sugar levels
- Lots of drug-drug interactions
Thyroid Hormone Drug Interactions
- Iron products
- Calcium supplements
- Soy isoflavones
- Food
- Raloxifene
- Cholestyramine
- Colestipol
- Oral contraceptives
- Phenytoin
- Carbamazepine
- Didanosine
Hypothyroid Drug Warning Labels
- AVOID ANTACIDS, DAIRY, AND IRON WITHIN 4 HOURS OF DOSE
- TAKE ON EMPTY STOMACH
- TAKE WITH FULL GLASS OF WATER
- TAKE IN THE MORNING
- DONT SKIP DOSES
