drugs for thyroid disorders

Question 1

what does the thyroid hormone secrete

Answer 1

• thyroxine (T4): most common
• triiodothyronine (T3)

T3 is the active form
- T4 must be converted

Question 2

control of thyroid

Answer 2

hypothalamus: TRH
ant pituitary: TSH
thyroid: T3, T4

negative feedback system to ant pit

Question 3

hypothyroidism

Answer 3

• deficiency in thyroid hormone
• primary: abnormality in thyroid gland
• secondary: cause is other body system dysfunction (pituitary or hypothalamus)

Question 4

hypothyroidism symptoms

Answer 4

in newborns/infants:
- low metabolic rate
- slowed growth and sexual development
- mental retardation

in adults:
- firm edema (myxedema)
- decrease metabolic rate (cold intolerance, weight gain)
- slow HR
- loss of mental and physical stamina
- loss of hair

Question 5

hypothyroidism goiter

Answer 5

• enlargement of thyroid gland
• overstimulation of thyroid gland from elevated TSH levels
• TSH elevated bc little negative feedback

Question 6

hyperthyroidism goiter

Answer 6

• excessive stimulation of thyroid gland
• increased release of T4 and T3

Question 7

hypothyroid treatment

Answer 7

• levothyroxine: synthetic thyroid hormone T4, replacement therapy, preferred drug used, may take 4-6 weeks for full effect, half life of 7 days

-liothyronine: synthetic T3, shorter half life and quicker action onset, onfet used in myxedema coma

Question 8

hypothyroidism treatment indications and moa

Answer 8

-unknown cause
- thyroid replacement in clients whose thyroid glands have been removed
- destroyed by radioactive iodine in treatment of thyroid cancer or hyperthyroidism

thyroid hormone replacements work in the same way as natural thyroid hormones

Question 9

thyroid hormone agents AE

Answer 9

• usually bc of drug excess (T4)
• signs of thyrotoxicosis
• cardiac dysrhythmias, tachycardia, angina, HTN
• insomnia, tremors, headache, anxiety
• nausea, diarrhea, menstrual irregularities
• weight loss, sweating, heat intolerance

Question 10

client care implications: treatment of hypothyroidism

Answer 10

• caution advised for people with cardiac disease, HTN
• not a cure (continue meds for life)
• take levothyroxine on empty stomach (before breakfast): food decreases absorption
• many drugs decrease absorptions (PPIs, antacids)

Question 11

hyperthyroidism

Answer 11

excessive thyroid gland activity
- graves disease: autoimmune (antibodies act like TSH and stimulate thyroid gland - goiter present)
- toxic nodular goiter - functionally autonomous nodules (thyroid gland tumour)

Question 12

hyperthyroidism complications

Answer 12

thyrotoxicosis
- CV: Hr increase, palpitations
- CNS stimulations: nervous, insomnia
- high metabolism rate
- increased appetite
- muscle weakness, atrophy

Question 13

treatment of hyperthyroidism

Answer 13

• radioactive iodine: destroys thyroid gland
• surgery to remove all or part of the thyroid gland
• antithyroid drugs (thioamide derivatives): methimazole, propylthiouracil (PTU)
• both drugs prevent thyroid hormone synthesis
• take 3-12 weeks for full effect

Question 14

hyperthyroid medication client care implications

Answer 14

antithyroid implications:
- give at same time each day to maintain consistent blood levels
- methimazole not used in first trimester of pregnancy (PTU preferred)

Question 15

antithyroid AE

Answer 15

• cold intolerance
• CNS depression
• edema