Thyroid And Antithyroid Meds

Front 1

hyperthryroidism

Back 1

-graves most common
-W>M
-excessive amts of T4 and T3

Front 2

Thyrotoxicosis (overactive thyroid)

Back 2

-Antithyroid drugs: Propothiouracil, Methimazole
-Radioactive Iodine (prob-can develop hypothyroidism)
-Beta blockers

Front 3

Polythiouracil (PTU) MOA

Back 3

-inhibits biosynthesis of thyroid hormone by serving as substrates for thyroid peroxidase and prevent incorporation of iodide into iodotyrosines
-inhibits coupling of of monoiodothyronine and diiodothyronine to form T4 and T3
-inhibits peripheral conversion of T4 to T3

Front 4

Polythiouracil pharm

Back 4

-PO
-PTU shorter half life
-safer in preg/lactation
-continuous therapy for 12-24 mo --> remission
-monitor frequently and make regular changes
-reduce dose slowly when euthyroid is achieved

Front 5

Methimazole

Back 5

-inihibits incorporation of iodide andi inhibits coupling of iodotyrosines to form T3 and T4
-more potent than PTU
-avg remission rates 40-50%
-4-8 wks sx diminish and T4 normalizes months later
-monitor and clinical every 2 months

Front 6

Antithyroid drugs-thioureas and SE

Back 6

1. transient leukopenia is common
2. rash is common
3. agranulocytosis: fever, sore throat, malaise, gingivitis, D/C
4. arthralgias
5. GI intolerance

Front 7

Iodides

Back 7

-used as adjunctive therapy with thioureas to prepare grave pts for surgery
-used to quickly block thyroid hormone release in severe thyrotoxicosis
-protect thyroid against radioactive iodine following nuclear situation
-MOA:high doses of iodide inhibit synthesis of iodotyrosine and iodothyronine and inhibit the release of thyroid hormone

Front 8

iodides available as

Back 8

1. potassium iodide saturated solution
2. used preop
3. used 3-6 days after RAI therapy

Front 9

iodides AE

Back 9

1. hypersensitivity reactions
2. salivary gland swelling
3. iodism (bitter metallic taste, sore tongue, sore throat)

Front 10

Radioactive iodine

Back 10

-MOA: taken up and incorporated into thyroid hormones and thyroglobulin
-Sodium Iodide 131
-efficacy very high!
-monitor- free thyroxine levels
AE: hypothyroid, C/I in PREG, mild thyroid tenderness and dysphagia

Front 11

Beta blockers

Back 11

-used to alleviate sx of hyperthyroidism
-used as adjunctive therapy with RAI, thioureas, or iodides
-propanolol commonly used

Front 12

thyroid storm

Back 12

-medical emergency with severe thyrotoxicosis
-clinical pres: hypothermic, temp of 105, sever anxiety, sweating, palpatations
-tx:
1. large doses of PTU
2. followed by iodines
3. esmolol
4. corticosteroids
5. supportive care

Front 13

hypothyroidism therapy

Back 13

-synthetic thyroid hormones: Levothyroxine (T4) (Synthroid or Levothyroid) (most common)
-cytomel (synthetic T3)- hard to dose
-Liotrix (mixed T3 and T4)
-Desiccated thyroid (Armour)
-avg maintenance is 110-120 MICROGRAMS/day

Front 14

Monitoring hypothyroidism

Back 14

-TSH and free T4 guides therapy and should be checked every 6 weeks after starting or changing until euthyroid
-monitor for signs of under or overdosages
-use lower dosages in elderly pts and those with cardiac dz

Front 15

AE of synthetic thyroid hormones

Back 15

1, heart failure
2, myocardial ischemia
3. start low (in elderly and sick pts) and titrate every 6 wks as needed
4. overdosage with suppression of TSH may cause reduced bone density (more common in postmenopausal women)

Front 16

Myxedema Coma

Back 16

-life threatening severe hypothyroidism
-clinical manifestations: extremely low HR, dec pulse, bradycardia, low temp, hyponatremia
Tx:
-IV thyroxine
-hydrocortisone
-BP and cardiac support as needed

Front 17

Special situations

Back 17

-preg hyperthyroid pts should be treated with PTU
-preg hypothyroid pts should be treated with levothyroxine
-elderly hypothyroid pts require lower initial dosages of synthetic thyroxine due to potential cardiac stress

Front 18

hypothyroidism and meds

Back 18

-inc sensitivity to digitalis
-may cause excessive anticoagulation in pts taking coumadin
-opiods and other resp depressants