Thyroid + Parathyroid Drugs

What is essential for the production of thyroid hormones?

iodine

How does iodine relate to hyperthyroidism and hypothyroidism?

hyperthyroidism will uptake more iodine than hypothyroidism (stimulating production of thyroid hormones)

What is hyperthyroidism?

excessive secretion of thyroid hormones (which increases the metabolic rate, so everything is sped up!)

What are symptoms of hyperthyroidism?

insomnia, tachycardia, hyperthermia, tremors, exophthalmos, weight loss

What is hypothyroidism?

diminished secretion of thyroid hormones (which slows the metabolic rate, so everything is slowed down!)

What are symptoms of hypothyroidism?

lethargy, weight gain, hypothermia, constipation

Which meds are patients with hypothyroidism sensitive to and why?

sedatives, opioids, + anesthetic agents (since the body’s already been slowed down, so the effects of these are worse)

What is the goal of thyroid drugs?

to restore a normal metabolism

Which drugs are used to treat hyperthyroidism?

methimazole, propanolol, radioactive iodine

Which med is used to treat hypothyroidism?

levothyroxine

What is the purpose of methimazole?

it inhibits the production of thyroid hormones

TRUE or FALSE: pregnant patients can take methimazole.

false

What are some side effects of methimazole?

hypothyroidism symptoms, bone marrow suppression, hepatotoxicity (jaundice, fever, abdominal pain), n/v

Which drug class does methimazole interact with?

anticoagulants (increased bleeding risk)

Which labs should be monitored with methimazole?

PTT/INR

How often should methimazole be administered?

q8h, with or without food

TRUE or FALSE: methimazole takes effect within days.

false (it takes days to weeks to start working)

TRUE or FALSE: stopping methimazole abruptly can cause thyroid storm.

true

Which products should be avoided when taking methimazole?

shellfish + iodine

How does propanolol work for hyperthyroidism?

it controls the symptoms of hyperthyroidism (but doesn’t treat the disorder), so it’s commonly used when first starting more long-term hyperthyroidism meds (like methimazole)

When should you NOT give propanolol?

if the patient is hypotensive or bradycardic

How does radioactive iodine help hyperthyroidism?

it reduces the size of the thyroid gland and destroys diseased thyroid tissue

TRUE or FALSE: radioactive iodine is given in three doses.

false; it’s given in a single dose

When is radioactive iodine contraindicated?

pregnancy + up to 6 weeks after cessation of lactation

TRUE or FALSE: radioactive precautions are necessary when taking radioactive iodine.

true (since radiation is emitted and excreted in all body fluids)

How long should radiation precautions last after discharge?

5-7 days

What are some in-patient radiation precautions?

stay in a hospital room specific to radiation, no visitors or personal belongings, don’t use public transportation to get home after discharge, + cluster nursing care

What are some general radiation precautions?

use disposable eating utensils, increase fluid intake (to flush out radiation), shower 2x/day + wash hair daily, + flush the toilet 2x after each use

What is levothyroxine used for?

hypothyroidism

What are side effects of levothyroxine?

hyperthyroidism symptoms (esp. weightloss), tachycardia/arrhythmias, tremors, HTN

Which patients should be cautious when taking levothyroxine?

patients with a known cardiac history

What are the administration instructions for levothyroxine?

take in the morning on an empty stomach!

When should you hold levothyroxine?

HR >100