Thyroid & Antithyroid drugs

Question 1

Thyroid Gland

main role

3 hormones

Answer 1

Secretes three hormones essential for proper regulation of metabolism:

Thyroxine (T4)
Tri-iodothyronine (T3)
Calcitonin

Question 2

Thyroid Gland is located near which gland?

function of this gland?

Answer 2

Located near the parathyroid gland, which is responsible for maintaining adequate levels of calcium in the extracellular fluid

Question 3

Four Functions of the Thyroid Gland

Answer 3

Regulate protein, lipid and carbohydrate metabolism

Assist with normal growth & development

Control thermoregulatory centre

Effect cardiovascular, neuromuscular, and endocrine systems

Question 4

Hypothyroidism:

Primary

Answer 4

Primary: abnormality in the thyroid gland itself

Question 5

Hypothyroidism:

Secondary

Answer 5

Secondary: results when the pituitary gland is dysfunctional and does not secrete thyroid-stimulating hormone (TSH)

Question 6

Hypothyroidism:

Tertiary

Answer 6

Tertiary: results when the hypothalamus gland does not secrete thyrotropin-releasing hormone, which, in turn, reduces TSH and thyroid hormone levels

Question 7

Congenital hypothyroidism

Answer 7

Hyposecretion of thyroid hormone during youth

Low metabolic rate, short stature, severely delayed sexual development, possible intellectual disabilities

Question 8

Myxedema

Answer 8

Hyposecretion of thyroid hormone during adulthood

Decreased metabolic rate, loss of mental and physical stamina, weight gain, loss of hair, firm edema, yellow dullness of the skin

Question 9

Goiter

Answer 9

Enlargement of the thyroid gland

Results from overstimulation due to increased levels of thyroid-stimulating hormone (TSH)

TSH is increased because there is little or no thyroid hormone in circulation.

Question 10

Hypothyroidism symptoms

Answer 10

Cold intolerance
Unintentional weight gain
Depression
Dry, brittle hair and nails
Fatigue

Late clinical manifestations:

Brdaycardia
Weight gain
Decreased LOC
Thickened skin
Cardiac complications

Question 11

Thyroid Replacement Drugs

Answer 11

levothyroxine (Synthroid®, Eltroxin®, Euthyrox®)

—-Synthetic thyroid hormone T4

Question 12

Thyroid drugs action?

Answer 12

replace what the thyroid gland cannot produce to achieve normal thyroid levels (euthyroid).

work the same way as endogenous thyroid hormones.

Question 13

Thyroid gland Indications

Answer 13

Used to replace what the thyroid gland itself cannot produce to achieve euthyroid condition (levothyroxine)

Indicated when there is a diagnosis of suspected hyperthyroidism (as in a thyroid-stimulating hormone–suppression test)

Used for prevention or treatment of various types of goiters

Replacement hormonal therapy for patients whose thyroid glands have been surgically removed or destroyed by radioactive iodine in the treatment of thyroid cancer or hyperthyroidism

Hypothyroidism of pregnancy

Question 14

Thyroid drugs Contraindications

Answer 14

MI, Adrenal insufficiency, hyperthyroidism

Question 15

Thyroid drugs Adverse Effects

Answer 15

Cardiac dysrhythmia is the most significant adverse effect.

May also cause (like hyperthyroidism):
Tachycardia, palpitations, angina, dysrhythmias, hypertension, insomnia, tremors, headache, anxiety, nausea, diarrhea, cramps, menstrual irregularities, weight loss, sweating, heat intolerance, fever, others

Question 16

Thyroid drugs Interactions

Answer 16

Enhance warfarin so reduce dose

Reduce efficacy of digoxin and insulin so increased dosage may be needed

Increased sensitivity to epinephrine

Cholestyramine, calcium and aluminum bind in GI tract and reduce absorption both drugs

Question 17

Thyroid drug important facts

Answer 17

Never discontinue abruptly

Give same time each day to maintain consistent blood levels
–Take in am to decrease insomnia

DO NOT INTERCHANGE BRANDS!
—Brands are not equivalent in dosing and can destabilize treatment

Question 18

Hyperthyroidism: Excessive Thyroid Hormones is caused by?

Answer 18

Graves’ disease

Multinodular disease

Plummer’s disease (rare)
–Also called toxic nodular disease

Thyroid storm (induced by stress or infection)
–Severe and potentially life-threatening

Question 19

Hyperthyroidism

define

symptoms

Answer 19

Affects multiple body systems, resulting in an overall increase in metabolism:

Diarrhea
Flushing
Increased appetite
Muscle weakness
Sleep disorders
Altered menstrual flow
Fatigue
Palpitations
Nervousness
Heat intolerance
Irritability

Question 20

Antithyroid Drugs

used to treat?

may cause____ &_____ toxicity?

Answer 20

Used to treat hyperthyroidism and to prevent the surge in thyroid hormones that occurs after surgical treatment or during radioactive iodine treatment for hyperthyroidism

May cause liver and bone marrow toxicity

Question 21

Treatment of Hyperthyroidism

Radioactive iodine:

Surgery:

Answer 21

Radioactive iodine (I131): works by destroying the thyroid gland “ablation”

Surgery to remove all or part of the thyroid gland
–Lifelong thyroid hormone replacement will be needed.

Question 22

Antithyroid drugs: thioamide derivatives

Answer 22

Propylthiouracil (PTU)

inhibition of iodine impedes thyroid hormone production

Propylthiouracil inhibits conversion of T4 to T3

Question 23

Nursing Implications

Answer 23

Assess for drug allergies, contraindications, and potential drug interactions.

Obtain baseline vital signs and weight.

Cautious use is advised for those with cardiac disease or hypertension and for pregnant women.

During pregnancy, treatment for hypothyroidism should continue.

Fetal growth may be retarded if maternal hypothyroidism is untreated during pregnancy.
–Adjust dosage every 4 weeks to keep thyroid-stimulating hormone at the lower end of the normal range.

Teach patients to take thyroid drugs once daily in the morning to decrease the likelihood of insomnia if taken later in the day.

Teach patients to take the medications at the same time every day and not to switch brands without primary care provider approval.

Teach patients to report any unusual symptoms, chest pain, or heart palpitations.

Teach patients not to take over-the-counter medications or herbal remedies without primary care provider approval.

Teach patients that therapeutic effects may take several weeks to occur.

Teach patients the importance of alerting health care providers of thyroid medication use.
–May enhance activity of anticoagulants
–Patients with diabetes may need increased dosages of hypoglycemic medications.
–May decrease serum digoxin levels

Question 24

Antithyroid medications nursing interventions

Answer 24

Better tolerated when given with food

Give at the same time each day to maintain consistent blood levels.

Never stop these medications abruptly.

Avoid the patient’s consumption of foods high in iodine (seafood, soy sauce, tofu, iodized salt).

Question 25

Monitor therapeutic response.

Answer 25

Thyroid drugs: decreased symptoms of hypothyroidism, improved energy levels, improved mental and physical stamina

Antithyroid drugs: no evidence of hyperthyroidism

Question 26

Watch for and monitor adverse effects of both drugs.

Answer 26

Thyroid drugs: cardiac dysrhythmia

Antithyroid drugs: leukopenia (manifested as fever, sore throat, lesions)

Question 27

Nursing Consideration Highlights

Answer 27

Monitor vital signs

Baseline TSH, T4, T3

Watching for signs of either HYPER or HYPO

It may take 3-4 weeks for thyroid drugs to take effect

Regular blood level monitoring required

Brand changes are not bioequivalent so not recommended to change brands