Thyroid Disorders- Follen

based off pp

Thyroid Hormone contains which of the following:

a. fluorine

b. nitrogen

c. iodine

d. sodium

c

Which is more potent? T3 or T4

T3

T4 and T3 are bound to _____ for transport.

TBG

thyroid hormone effects on fetuses:

growth and development

Does thyroid hormone increase or decrease metabolism?

increase

Which of the following does thyroid hormone have a role in?

a. cartilage formation

b. temperature regulation

c. protein formation

d. bone growth

b

What are the primary causes of hypothyroidism?

• iodine deficiency

• autoimmune destruction

• drugs/ hyperthyroidism tx

What are secondary causes of hypothyroidism?

tumors

What are the symptoms of hypothyroidism?

“COLD AND FAT”

• cold intolerance

• fatigue

• weakness

• low HR

• goiter

• others: constipation, dry skin, cramps, myalgia, depression

When diagnosing hypothyroidism, usually what levels are measured first? second?

TSH levels first, then T4 levels

If a patient had high TSH levels and normal T4 would you treat the patient?

It depends— tx if T4 is normal is on a case-to-case basis

What is the drug of choice for treating hypothyroidism?

levothyroxine

What is the PO to IV conversion for levothyroxine?

reduce oral dose by 25-50% when converting to IV

Is it okay to switch from brand to generic levothyroxine?

should be avoided

What is the dosing for levothyroxine in a healthy patient ≤60 ?

1.6mcg/kg/day

What is the dosing for levothyroxine in a healthy patient >60 ?

25-50 mcg/day

What is the dosing for levothyroxine in patients with coronary heart disease?

12.5-50mcg/day

Dose adjustments for levothyroxine are…

12-25 mcg/day every 4-6 weeks until normal thyroid levels

Patients on levothyroxine should be monitored every…

every 6 months and then 12 month intervals

What drug interactions with levothyroxine decreases absorption?

• antacids

• bile acid sequestrants

• iron salts

• multivitamins

• biphosphonates

What counseling should you give to a patient regarding administration of levothyroxine?

• take every morning on empty stomach

• take with a glass of water

• wait 30-60 minutes before breakfast

• DO NOT administer within 4 hours of calcium/iron

• alternative: take at bedtime 3-4 hours after last meal

Boxed warning of levothyroxine:

• do not use for weight loss

• high doses may produce serious/life threatening toxic effects

Besides levothyroxine what are some other drugs that can be used for hypothyroidism?

• liothyronine

• liotrix

• desiccated thyroid

What is the drug of choice in hypothyroidism DURING PREGNANCY?

levothyroxine

What are some complications of hypothyroidism?

• depression

• metabolic problems

• myxedema coma

A myxedema coma is a rare state caused by long-standing hypothyroidism+ inciting event. What is the treatment?

IV levothyroxine

What are some endogenous causes of hyperthyroidism?

• grave’s disease

• toxic goiter

• tumor

What are some exogenous causes of hyperthyroidism?

drugs (iodine, interferons, amiodaraone)

What are some symptoms of hyperthyroidism?

“HOT AND SKINNY”

• heat intolerance

• weight loss

• CNS (agitation, nervous, irritable)

• tachycardia

• thin hair

• goiter

• diarrhea

• bulging eyes

For hyperthyroidism what drug can be used for symptom management if HR>90 bpm?

beta-blockers

If beta-blockers are contraindicated in symptom management of hyperthyroidism, what can be used?

• clonidine

• verapamil/diltizem

What is the advantage of thioamides in the treatment of hyperthyroidism?

allows for possible remission and avoid life-long therapy

What is the MOA of thioamides?

inhibit TPO

What 2 drugs are thioamides?

• propylthiouracil

• methimazole

Of the 2 thioamides, which is 1st line?

methimazole

Which thioamide is preferred in the 1st trimester of pregnancy and during a thyroid storm?

propylthiouracil

What is the boxed warning of propylthiouracil?

liver toxicity

What is the duration of therapy for thioamides? What happens after that duration?

12-18 months

• then reassess, consider other tx options or continue therapy for another 12-18 months

Can radioiodine ablation be used during pregnancy?

no

If thyroid ablation with radioactive iodine is successful, what will patients need to do for the rest of their life?

thyroid hormone supplementation

What are some complications of hyperthyroidism?

• CV

• osteoporosis

• thyroid storm

What is the treatment for a thyroid storm?

• IV bb’s

• antithyroid drugs (PTU preferred)

• iodides

• corticosteroids