actions of the thyroid gland
produces two thyroid hormones using iodine from diet
removes iodine from blood, concentrates it, and prepares it for attachment to tyrosine
functions of thyroid hormones
metabolism thermoregulation O2 demands, cardiac output, blood volume enzyme system activity growth/development
hypothyroidism causes
absence of thyroid gland
deficient dietary iodine
lack of functioning thyroid tissue 2/2 tumor, autoimmune disorders
lack of TRH r/t tumor, hypothalamus disorder
hypothyroidism treatment
levothyroxine (synthroid, levoxyl, levo-T, levothroid) is a synthetic salt of T4
levothyroxine action
increases metabolic rate of body tissues, increasing O2 consumption, respiration, HR
acts as replacement for natural thyroid hormone and used as replacement therapy in hypothyroidism
levothyroxine pharmacokinetics
given PO
metabolized in liver
excreted in bile
onset 6-8 hrs
levothyroxine contraindications
hypersensitivity
thyrotoxicosis
acute MI complicated by hypothyroidism
levothyroxine adverse effects
HTN, tachycardia, sweating, heat intolerance arrhythmias anxiety headache GI irritation (n/v/d)
levothyroxine interactions
“many” – powerpoint
levothyroxine interventions
max therapeutic effect: replacement therapy is lifelong; monitor cardiovascular response and serum thyroid function
min adverse effect: young adults without CAD can begin full replacement dose of levothyroxine
levothyroxine + pregnancy
pregnancy category A
hyperthyroidism causes
Graves’ disease
excessive amounts of thyroid hormones are produced and released into circulation
hyperthyroidism s/s
increased body temp, heat intolerance, flushing tachycardia, palpitations, HTN thin skin weight loss, amenorrhea goiter
hyperthyroidism treatment
thyroid-hormone antagonist drugs
surgery
radioactive iodine
prototype: methimazole (MMI)
methimazole action
palliative treatment of hyperthyroidism that inhibits synthesis of thyroid hormones
methimazole pharmacokinetics
given PO
metabolized in liver
excreted in urine
methimazole contraindications
hypersensitivity
methimazole adverse effects
hives, itching, rash joint swelling, arthralgia vertigo drowsiness n/v altered taste sensation
methimazole drug interactions
beta-blockers
theophylline
warfarin
methimazole interventions
max therapeutic effect: ensure proper administration
min adverse effect: blood tests to monitor hematologic and thyroid function; monitor bone marrow function
iodine solution (Iugol’s) actions
cause thyroid cells to become oversaturated with iodine and stop producing thyroid hormone
iodine solution indications
presurgical supposition of thyroid gland
acute thyrotoxicosis
emergency thyroid blocking in radiation emergency
iodine solution pharmacokinetics
given PO
metabolized in liver
excreted in urine
iodine solution adverse effects
hypothyroidism, goiter
swelling of salivary glands
iodism (metallic taste, sore mouth/throat/gums, n/v/d, cold sx)
allergic rxn