Thyroid & Systemic Steroids & Autoimmune Disorders Flashcards
(45 cards)
What are the 2 hormones produced by the thyroid? Which one is more potent? What element can only the thyroid absorb and why is it necessary?
The thyroid gland produces triiodothyronine (T3) and thyroxine (T4). T3 is more potents, but T4 has a shorter half-life.
The thyroid gland is the only organ that can absorb iodine. Iodine is required for the production of T3 and T4.
Which key drugs can cause hypothyroidism? (I TALC)
I - interferons
T - tyrosine kinase inhibitors (ex. sunitinib)
A - amiodarone
L - lithium
C - carbamazepine
(Hashimoto’s Disease can also cause hypothyroidism
What is Hashimoto’s Disease?
Hashimoto’s Disease is an autoimmune condition where a patient’s own antibodies attack the thyroid gland. It is the most common cause of hypothyroidism.
What are 3 brand names of levothyroxine (T4)? What is the full replacement dose? What does should be started if the pt has CAD? What is the IV to PO ratio for levothyroxine?
Levothyroxine (Synthroid, Levoxyl, Unithroid)
Full replacement dose = 1.6mcg/kg/day
- start w/ full replacement dose in healthy, young (< 50 yo) patients
If known CAD, start with 12.5-25mcg/day
IV to PO ratio is 0.75:1
What is the brand name of thyroid, desiccated USP (T3 and T4)? What is the brand name of liothyronine (T3)? Why can liothyronine cause fluctuations in T3 levels?
Thyroid desiccated USP (Armour Thryoid)
Liothyronine (Cytomel)
- has a shorter half-life, which can causes fluctuations in T3 levels
What is the order of levothyroxine colors from lowest to highest strength? (Orangutans Will Vomit On You Right Before They Become Large, Proud Giants)
25mcg - orange
50mcg - white
75mcg - violet
88mcg - olive
100mcg - yellow
112mcg - rose
125mcg - brown
137mcg - turquoise
150mcg - blue
175mcg - lilac
200mcg - pink
300mcg - green
What are are 4 drugs/classes of drugs that can decrease absorption of levothroxine?
- antacids
- cholestyramine
- sevelamer
- sucralfate
What is the most common cause of hyperthyroidism?
Graves’ disease is the most common cause of hyperthyroidism. It is an autoimmune disorder where the antibodies stimulate the thyroid to produce too much T4.
What are the treatment options for hyperthyroidism?
Treatment involves antithryoid medications, destroying part of the gland via radioactive iodine, or surgery.
- pts can be treated with beta blockers first for symptom control (reduce palpitations, tremors, and tachycardia)
Meds:
- propylthiouracil (PTU) or methimazole can be used as a temporary measure until surgery is complete.
- it takes 1-3 mo of treatment w/ antithyroid meds at high doses to control symptoms. Once symptoms are controlled, the dose should be reduced to prevent hypothyroidism from occurring
What is the MOA of propylthiouracil and methimazole? What are 2 boxed warnings for PTU? Which one is the drug of choice? In what circumstances is the other drug the drug of choice?
MOA - inhibits synthesis of thyroid hormones by blocking the oxidation of iodine in the thyroid gland.
- PTU also inhibits peripheral conversion of T4 to T3
PTU boxed warnings
- severe liver injury and acute liver failure
- pregnancy: preferred in 1st trimester
Drug of choice is methimazole (due to lower risk of liver damage) EXCEPT in the below scenarios:
- PTU is preferred in thyroid storm
- PTU is preferred if methimazole is not tolerated
- PTU is preferred in the 1st trimester of pregnancy (methimazole is preferred in 2nd and 3rd trimester)
What should be taken immediately after radiation exposure and why?
Potassium iodide (KI) should be taken as soon as possible after radiation exposure because it blocks the accumulation of radioactive iodine, thus preventing thyroid cancer.
What are symptoms of thyroid storm?
Fever (>103º F)
Tachycardia
Tachypnea
Dehydration
Profuse sweating
Agitation
Delirium
Psychosis
Coma
What are our treatment options for thyroid storm?
Antithyroid drug therapy (PTU preferred)
+
Inorganic iodide therapy (SSKI or Lugol’s solution)
+
Beta-blocker (propranolol)
+
Systemic steroid (dexamethasone)
+
Aggressive cooling w/ acetaminophen and cooling blankets, other supportive treatments
What is our preferred treatment option for hypothyroidism in pregnancy?
Levothyroxine is safe in pregnancy and is the recommended treatment. Pregnant women will require a 30-50% increase in the dose.
Which 3 steroids are commonly used as adrenal hormone replacement therapy and have glucocorticoid activity? Which steroid has mineralocorticoid activity?
Glucocorticoid (anti-inflammatory effects)
- prednisolone
- cortisone
- hydrocortisone
Mineralocorticoid activity (maintain water and fluid balance)
- fludrocortisone (mimics aldosterone)
What are the differences between Cushing’s disease and Addison’s disease?
Cushing’s: can develop when the adrenal gland produces too much cortisol or is exogenous steroids are taken in higher doses
Addison’s: the adrenal gland is not taking enough cortisol.
- if exogenous steroids are abruptly stopped, it can cause Addisonian Crisis, which can be fatal due to volume depletion and hypotension
What is the order of steroids from least potent to most potent? What are their equivalent doses to prednisone 5mg? (Cute Helpful Pharmacists and Physicians Marry Together & Deliver Babies)
Least: cortisone (25mg)
hydrocortisone (20mg)
prednisone (5mg)
prednisolone (5mg)
methylprednisolone (4mg)
triamcinolone (4mg)
dexamethasone (0.75mg)
Most: betamethasone (0.6mg)
What are the brand names of these steroids:
- dexamethasone
- hydrocortisone
- methylprednisolone
- prednisolone
- triamcinolone
Which drug is a prodrug of cortisol? Which drug is a prodrug of prednisolone?
dexamethasone (Decadron)
hydrocortisone (Solu-Cortef)
methylprednisolone (Medrol, Solu-Medrol)
prednisolone (Millipred, Orapred ODT)
triamcinolone (Kenalog)
Cortisone is a prodrug of cortisol
Prednisone is a prodrug of prednisolone
When is a patient immunosuppressed from steroids?
A pt is immunosuppressed if using ≥ 2mg/kg/day or ≥ 20mg/day of prednisone or equivalent for > 2 weeks
If immunosuppressed, avoid live vaccines and taper when d/c steroids due to HPA axis suppression.
What 4 conditions can using strong immunosuppressants increase the risk of?
- reactivation of tuberculosis or hepatitis (B or C): testing/treatment must be done prior to starting immunosuppressive drugs
- viruses
- lymphomas and certain skin cancers
- infections
What are 4 classic articular symptoms of RA?
*typically bilateral and symmetrical (unlike OA)
- joint swelling
- pain
- stiffness
- bone deformity
What is the preferred initial therapy for RA? When should a patient be started on a disease-modifying antirheumatic drug (DMARD)? What can be used to “bridge” patients until their DMARD starts working?
Methotrexate is the preferred initial therapy for most patients.
- never use two biologic DMARDs in combination, due to their risk of serious infections
Patients with symptomatic RA should be started on DMARD therapy, regardless of their severity of the disease, since DMARDs slow the disease process and help prevent further joint damage.
Steroids and NSAIDs can be used to bridge patients.
What are the 4 traditional DMARDs?
methotrexate
hydroxychloroquine
sulfasalazine
lefunomide
What is the brand name of methotrexate? What is the MOA of MTX? What is the dosing? What are 4 boxed warnings? What are 4 monitoring parameters? What can be given to decrease hematological, GI, and hepatic side effects?
methotrexate (Trexall)
- Trexall is the oral tablet. There are SC auto-injectors as well
MOA: inhibits dihydrofolate reductase, which inhibits folate, which results in anti-inflammatory activity
Dosing: 7.5-20mg once weekly
Boxed warnings:
- hepatotoxicity
- myelosuppression
- mucositis/stomatitis
- teratogenic
Monitoring:
- CBC
- LFTs
- chest x-ray
- hepatitis B and C serologies
Can give folate to reduct hematological, GI, and hepatic side effects.
