Drugs for thyroid

1. stimulates energy use

2. stimulate the heart

3. promote growth and development

actions of thyroid hormone [4]thy

1. Serum TSH

2. Serum T3

3. Serum T4

thyroid function tests [3]

Ability to produce T3 and T4

TSH levels indicate:

Malfunction of the thyroid

hashimotos diseaese (autoimmune)

insufficient iodine

surgical removal of the thyroid

insufficient release of TSH

causes of hypothyroidism

Levothyroxine (Synthroid)

Synthetic preparation of T4 and drug of choice for hypothyroidism

Side effects are jitters and increased HR. Should be taken in the morning 30-60 minutes before breakfast. Don’t want it at night when you’re trying to sleep.

When should Synthroid be taken? Why?

1. tachycardia

2. angina

3. tremors

Adverse effects of synthroid: [3]

1. Calcium and iron suppliments

2. H2Ras

3. PPIs

Drugs that reduce synthroid levels: [3]

1. dilantin

2. tegretol

3. rifampin

Drugs that accelerate synthroid metabolism: [3]

Synthroid will lead to a breakdown of vitamin K dependant clotting factors. IF you take warfarin and synthroid, increases the actions of warfarin and increased risk of bleeding

Warfarin and synthroid drug interaction:

HPA. INcreased tachycardia and tremors.Two

SYnthroid and catecholamines interaction:

1. Grave’s disease

2. Toxic Nodular Goiter (Plummer’s disease)

Two forms of hyperthyroidism:

Thyroid stimulating immunoglobulins

Cause of hyperthyroidism:

Thyroid hormone stimulates heart rate, so people with hyperthyroidism typically have a faster HR. Give beta blockers if needed to slow HR

Beta blockers for hyperthyroid disease (why?)

Decreased thyroid hormones

Nonradioactive iodine on thyroid hormone:

1. surgical removal of thyroid

2. destruction of thyroidtissue (radiation)

3. suppression of thyroid hormone synthesis

Treatment for hyperthyroidism: [3]

Thyrotoxic crisis (Thyroid storm)

People wth thyrotoxicosis who undergo significant stress (illness, surgery). Get MEGA rapid hyperthyroidism. Cannot be predicted with lab work, but at risk if hyperthyroidism

1. hyperthermia

2. severe tachycardia

3. restlessness

4. agitation

5. tremor

6. unconscious

7. coma

8. hypotension

9. heart failure

Signs of thyroid storm: [9]

1. methimazole

2. beta blocker (to lower HR)

3. Sedation, cooling, glucocorticoids, IV fluids.

THyroid storm treatment: [3]

lower heart rate. Sometimes it can reach 210-212.

Priority action in pt with thyroid storm

Methimazole

First line prototype thionamide. Used in hyperthyroidism.

Euthyroid state

Normal tyroid hormone levels

More dangerous during first trimester and lactation. Can also be teratogenic.

Methimazole in pregnancy:

Can cause agranuocytosis (low white blood cells). Might not be able to respond to infection.

methimazole effect on white blood cells

1. sole form of therapy for Grave’s disease

2. adjunct to radiation therapy

3. suppresses thyroid hormone synthesis in preparatino for thyroid gland surgery

4. thryotoxic crisisSc

WHen is methimazole used: [4]

Propylthyroucacil (PTU)

Inhibits thyroid hormone synthesisSecond-line treatment for Grave’s diesase, but can be more effective for use during Thyroid storm than methimazole

1. Agranulocytosis

2. Hypothyroidism (lowers TH too much)

3. Severe liver damage

Adverse effects of PTU [3]

1. PTU in first semester

2. Methimazole in second and third

What hyperthyroidism meds should be used in which trimester of pregnancy?

Crosses the placenta less readily than methimazole, but still can harm developing fetus and breastfeeding infantWh

PTU in pregnancy:

PTU blocks conversion of T4 to T3 in the periphery, whereas methimazole dose not.

Why is PTU more effective in thyroid storm?

PTU has a shorter half-life than methimazole (90 minutes verses 6-13 hours) so it requires 2-3 daily doses compared to 1

Which hyperthyroidism drug has a shorter half life?