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Thyroid Gland Drugs

 

Synthetic

thyroid

hormones

(others:

Liothyronine (T3) & Liotrix)

Levothyroxine (T4) Use: Hypothyroidism- Congenital: Cretinism- Childhood hypothyroidism- Adult hypothyroidism: Hashimoto’s thyroiditis- Myxedema coma

o ccurs in elderly during the !inter

o Medical emergency

o Hypothermia" resp# distress" loss o$

consciousnesso May also try %& 'iothyronine

 Anti-thyroid drugs Use: Hypothyroidism

- rae’s disease: *C is Methima+ole 

Thioamides

*All 3 cross the

placenta;

though T!

crosses it theleast

ropythiouracil

(T!)

"ethi#a$ole

%ari#a$ole

,Methima+ole is longeracting more potent thus

is the *C $or

hypothyroidism

 Toxicity:

- Maculopapular rash- Agranulocytosis (./00)- Hepatitis (1TU)

MA: (-) thyroid peroxidase  2o iodine oxidation3 no

M%T3*%T coupling,1TU can also (-) peripheral conersion o$ T4 to T

 Anion

inhibitors

*These are less

i#portant'

no A

erchlorate (%l+,-)

ertechnetate

(Tc+,-)

Thiocyanate (.%/-)

MA: competitie (-) 2a53%odide transporter  (-) upta6e o$

iodide

A7: aplastic anemia (thus no longer used)

Use: Amiodarone-induced thyrotoxicosis

Iodine &

Iodides

*0ol1-%haio2

e2ect: large

doses o1 iodine

(-) 1urther

synthesis o1

iodine

Lugols 4odine (45 6

74)

/a 4odide

7 4odide

MA: (-) hor#one release  dec# ascularity" si+e"

$ragility o$ a hyperplastic gland

Use: pre-operatie preparation

 Thyroid escape: gland escapes $rom the iodide 8loc6 in 9-

!ee6s%odinated contrast

media: Diatri$oate

4ohexol

Use: *iagnosis o$ hypothyroidism

Radioactive

Iodine

*+utpatient tx8

per#anent

cure8 ut slo

response &

9 eco#e

hypothyroid

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 Adrenorecepto

r blocking

agents

"etoprolol

ropanolol

Atenolol

Use: (-) symptoms o$ thyrotoxicosis> palpitation"

nerousness" tremors

1ropanol in high doses: (-) peripheral conersion o$ T4 to T

Toxic stor#: sudden acute exaceration o1 all o1 the sy#pto#s o1 thyrotoxicosis (opposite o1

#yxede#a co#a)

Treat#ent: (3 s)

• To rapidly control cardiac #ani1estations:

o ropranolol 4=: also (-) peripheral conversion o1 T, to T3

o +r Diltia$e# 4= (%a56 channel locer): give instead o1 propranolol i1 the

patient has %>? or asth#a

• To rapidly (-) release o1 T3 and T, 1ro# the thyroid gland: +ral otassiu# iodide

• To (-) synthesis o1 T3 and T,:

o ropylthiouracil: D+% @c it also (-) peripheral conversion o1 T, to T3

o +r "ethi#a$ole

• To treat the shoc: >ydrocortisone 4=: also (-) peripheral conversion o1 T, to T3

• .upportive therapy 1or 1ever8 heart 1ailure8 or any underlying disease that #ay have

precipitated the stor#

A#iodarone induced thyrotoxicosis (A#iodarone causes hyperthyroidis# @c it has iodine

Large doses o1 iodine can cause hyperthyroidis# in a patient ho previously had

hypothyroidis#)• Type 4: iodine induced

o Treat#ent: T!

• Type 44: inBa##atory

o Treat#ent: .teroids

Cadiation exposure containing radioactive iodine  taen up into the gland  thyroid cancer

• rophylaxis: +ral otassiu# iodide