EDGEWOOD COLLEGE
EDGEWOOD COLLEGE
School of Nursing
N 312
Drugs for Thyroid Disorders
Four steps in synthesis of thyroid hormones:
1. transport and concentration of iodide into thyroid
2. iodide undergoes oxidation to form iodine (enzyme peroxidase
needed)
3. activated iodine becomes incorporated into tyrosine
residues
4. iodinated tyrosine molecules are coupled
T4: thyroxine (half-life of 1 week)
T3: triiodothyronine (half life of 1.5 days)
TSH: thyroid stimulating hormone (most sensitive for diagnosing
hypothyroidism)
I Hyperthyroidism hyperactivity of the thyroid gland, secreting
excessive amounts of thyroid hormones. Graves disease, an
autoimmune disorder, is the most common form. Treated with
antithyroid drugs, radioactive iodine or surgery.*Signs and
symptoms- elevated HR, palpations in chest, anxiousness, insomnia,
intolerance to heat, increased appetite, weight lost, deep tendon
reflexes very activePTU (propylthiouracil): inhibits at Step 2
(oxidation of iodide) and Step 4 (prevents iodinated tyrosine from
coupling). Also inhibits conversion of T4 to T3 in periphery. PTU
does not destroy existing stores of thyroid hormone, therefore may
take 1-2 weeks to take effect. Antithyroid
Oral medication
Inhibits conversion of T3 T4 to active form
Major side effect: agranulocytosis (( WBC)
*Black box warning acute liver failure 1/10,000 s/s abd. Pain,
jaundice, appetite.
Radioactive Iodine (131 I): destroys thyroid tissue by emission
of beta particles.
Advantages: low cost, no surgery, not life-threatening, no other
tissue destroyed
Disadvantages: delayed onset up to several months, significant
onset of hypothyroidism ( = 10-30%)
Propranolol beta-blocker used to treat S/S of hyperthyroidism
until drugs take effect.
Hypothyroidism: severe form in adults> myxedema. In
children> cretinism.
In iodine sufficient areas, principle cause is autoimmune
thyroiditis (Hashimotos
Disease). Other causes are insufficient iodine in the diet put
in salt now,
iatrogenic from tx. of hyperthyroidism.
**common disorder
**often as a result of being treated for
hyperthyroidismLevothyroxine (T4) synthroid: synthetic thyroid
replacement. Taken orally without
food. Often life-long therapy is needed. If excessive, danger of
thyroid storm or
thyrotoxicosis developing. Has a long half-life, 7 days, takes
28 days to reach peak.Thyroid Storm:-excesive hormone release
-very elevated HR, BP
-can be treated with beta-blockersEvery day dosing necessary.
Need to monitor closely in those with cardiovascular
disease.
(absorption with aluminum antacids, ferrous sulfate, calcium
supplements
( effects of warfarin (coumadin)
Corticosteroid therapy in non-endocrine disorders
Corticosteroids: powerful anti-inflammatory and
immunosuppressive action.
Normally, released by the adrenal glands. Made up of
mineralocorticoid and
glucocorticoid hormones. Also, regulate electrolyte balance by
sodium and water reabsorption. Regulate protein, carbohydrate, and
fat metabolism.
Therapy for long-term management of chronic inflammatory
diseases, such as
rheumatoid arthritis, lupus, colitis, asthma, & COPD. Used
for suppression of
inflammatory response during organ transplant. Therapy for
short-term tx. of acute dermatitis, bronchitis, spinal cord injury
and soft tissue injury. Available as an oral, parenteral,
topical,
inhaler, and ophthalmic ointment.
Disadvantage: steroids affect the bodys metabolic functions,
they should be given
only when the benefits outweigh the risks. There are many
associated side effects with
long-term corticosteroid therapy. * can reactivate TB, should
not be used with a live virus administration since inflammatory
response is suppressed*contraindicated
in fungal infections.
Prednisone inhibits release of mediators that promote the
inflammatory response.
Inhibit release of macrophages and inhibit increase in vascular
permeability. Promotes
protein, fat, carbohydrate breakdown.
Side effects: inhaled steroid use ( risk for oral candidiasis
(yeast infection)
At risk for hypokalemia, monitor drug interactions that also
cause loss of K+. Impaired wound healing, osteoporosis, weight
gain, development of diabetes.
Long-term use will suppress the normal function of the adrenal
gland. If steroids are suddenly stopped the adrenal gland is unable
to secrete.
DO NOT STOP DRUG - MUST TAPER - Can be life threatening.
