Pharm - Hypothyroidism Flashcards
What is the standard therapy for treating hypothyroidism?
levothyroxine
what are the two main types of antithyroid agents?
methimazole and propylthiouracil
what is the mechanism of action of methimazole?
it decreases the production of hormone by inhibiting iodination of tyrosine
what are the adverse effects of propylthiouracil?
skin rash, allergic reactions, agranulocytosis, and severe heptaotoxicity
what is the purpose of radioactive iodine in thyroid treatment?
to ablate thyroid tissue in patients with Graves disease and toxic nodules
what are common symptoms of hyperthyroidism?
elevated heart rate, hypertension, weight loss, and nervousness
what is the average adult replacement dose of Levothyroxine?
1.6 mcg/kg/day
how do you convert levothyroxine dosage to desiccate thyroid dosage?
multiply the levothyroxine dose by 0.65
What is the primary cause of hypothyroidism in North America?
hashimoto’s thyroiditis
what is a thyroid storm?
a life-threatening medical emergency caused by severe thyrotoxicosis
What should be monitored after prescribing Levothyroxine?
TSH levels, typically adjusted every 6 weeks
what are the adverse effects of levothyroxine if overdosed?
symptoms of hyperthyroidism, possible exacerbation of angina
what is the role of Beta blockers like propranolol in thyroid disorders?
to ameliorate symptoms of adrenergic excess caused by excess thyroid hormone
when is propylthiouracil preferred over methimazole?
during the first trimester of pregnancy
what is the goal of therapy for thyroid disorders?
achieve a euthyroid state and manage symptoms
what are the common causes of thyrotoxicosis?
graves disease, toxic nodules, iodine excess, and TSH-producing pituitary adenomas
what is the typical initial dosing range for Levothyroxine in patients with mild symptoms?
25 to 50 mcg/day
How long does it take to reach a new steady state after adjusting Levothyroxine dosage?
6 weeks
what is the risk associated with thyroid surgery?
development of hypothyroidism
What is the preferred medication for treating thyroid storm?
propylthiouracil
what are the adverse effects of desiccated thyroid?
cardiovascular and neurological effects, including palpitations, tachycardia, and nervousness
what factors can reduce the absorption of Levothyroxine?
antacids, mineral supplements, proton pump inhibitors, and estrogens
what is the significance of TSH levels in thyroid treatment?
TSH levels guide dosage adjustments for Levothyroxine therapy
what is the dosing calculation for a patient weighing 102 kg with a TSH of 21.3 U/mL?
use the equation: 107 + 0.69(TSH) -> 107 + 0.69(21.3) = 121 mcg
what is the role of fine needle biopsy in thyroid disorders?
to diagnose thyroid nodules that require cytologic evaluation
what are the contraindications for using methimazole?
it is contraindicated during the first trimester of pregnancy due to the risk of aplasia cutis
what is the mechanism of action of propranolol in the context of hyperthyroidism?
it decreases the conversion of T4 to T3 and alleviates symptoms of adrenergic excess
what should be done if a patient’s TSH remains unchanged after 6 weeks on Levothyroxine?
consider changing the time the patient take their iron supplement, as it may interfere with absorption
