Week 6) NR 565 Week 6 Study Guide
Hypothyroidism - ANSWER:underproduction of the hormone thyroxine (T4) (yellow)
Too little thyroxine=slower metabolism
fatigue, depressed mood, slow heart rate, constipation, weight gain, and irregular menstrual periods.
MC in >60 women
Hyperthyroidism - ANSWER:overproduction of thyroid hormones: triiodothyronine (T3) (green), and
thyroxine (T4) (yellow)
What active hormones are produced by the thyroid? - ANSWER:triiodothyronine (T3) and thyroxine (T4,
tetraiodothyronine)
4 steps to synthesis of thyroid hormoness - ANSWER:1. Uptake
2. Activation (Oxidation by peroxidase)
3. Iodination of Tyrosine
4. Coupling of Iodinated Tyrosine
3 Principle Actions of Thyroid Hormones - ANSWER:(1) stimulation of energy use
(2) stimulation of the heart
(3) promotion of growth and development
Most sensitive method for diagnosing hypothyroidism - ANSWER:Serum TSH
Levothyroxine Dosage in adults - ANSWER:100-125ug for 70kg adult
ORAL
Older adults- start at 25-50ug daily
Levothyroxine dose in Myxedema Coma - ANSWER:200-500 ug once
INJECTION
Addition dose of 100-300 ug can be given a day later
Levothyroxine dose for Congenital Hypothyroidism - ANSWER:<3mo: 10-15mg/kg
3-5mo: 8-10mg/kg
6-11mo: 6-8mg/kg
1-5yrs: 5-6mg/kg
6-12 yrs: 4-5mg/kg
ORAL
,Dose DECREASES with age.
Dose adjusted to normalize TSH and free T4
Levothyroxine dose for simple goiter - ANSWER:100-200ug
ORAL
Baseline data for levothyroxine - ANSWER:Serum levels of TSH and free T4
What are thionamide drugs - ANSWER:For hyperthyroidism
ex. methimazole and propylthiouracil (PTU)
Suppresses synthesis of thyroid hormones
long term-hyperthyroidism
short-term- subtotal thyroidectomy or tx with radioactive iodine
Frequency of therapy for Methimazole and Propylthiouracil - ANSWER:Methimazole: Initial therapy-3
times a day
Maintenance therapy- Once a day
Propyltiouracil:
Initial therapy- 3 or 4 times a day
Maintenance therapy- 2 or 3 times a day
What is a first-line drug for hyperthyroidism - ANSWER:Methimazole (Tapazole)
Methimazole - ANSWER:inhibits thyroid hormone synthesis--> DOES NOT DESTROY EXISTING STORES OF
THYROID HORMONE
SAFER and more convenient than PTU and preferred more
EXCEPT in those who are pregnant or breastfeeding and those who are in thyrotoxic crisis
May take 3-12 weeks to produce euthyroid state
Baseline data for methimazole - ANSWER:Obtain serum levels of thyroid-stimulating hormone (TSH), free
triiodothyronine (T3), and free thyroxine (T4). Check baseline CBC and LFTs prior to initiation.
Radioactive Iodine in Graves Disease - ANSWER:Used to destroy thyroid tissue
want remission without complete destruction of gland
however delayed hypothyroidism due to excessive thyroid damage is frequent complication
, Radioactive Iodine - ANSWER:Destruction of thyroid tissue produced primarily by emission of beta
particles
Don't travel outside of thyroid
initial effects days to weeks, full effects develop 2-3 months
66% cured with single exposure, others 2-3 tx more
Don't give to very young, pregnancy or breastfeeding
Dosage dependent on thyroid sixe and rate of thyroidal iodine uptake
Graves- usual 4-10mCi
Nonradioactive Iodine: Lugo Solution - ANSWER:AKA "strong iodine solution"
5%elemental iodine and 10% potassium iodide
Mechanism of action for Nonradioactive Iodine - ANSWER:Paradoxical suppressant effect on the thyroid
1st- high conc. of iodide decrease iodine uptake by thyroid
2nd- high conc. of iodide inhibit thyroid hormone synthesis by suppressing both the iodination of
tyrosine and coupling of iodinated tyrosine residues
3rd- high con. of iodine inhibit release of thyroid hormone into blood
All 3 combine to decrease circulating levels of T3 and T4
not sustained indefinitely
Therapeutic use Nonradioactive iodine - ANSWER:prep for thyroidectomy
initial effect w/in 24 hours
peak effect in 10-15 days
usually methimazole then nonradioactive iodine
Usually given with PTY last 10 days before surgery
also in thyrotoxic crisus
Dosage and administration of nonradioactive iodine - ANSWER:5-7 drops 3 times daily for 10 days
immediately preceding surgery
mix with juice or some other beverage
Hypothyroidism - ANSWER:underproduction of the hormone thyroxine (T4) (yellow)
Too little thyroxine=slower metabolism
fatigue, depressed mood, slow heart rate, constipation, weight gain, and irregular menstrual periods.
MC in >60 women
Hyperthyroidism - ANSWER:overproduction of thyroid hormones: triiodothyronine (T3) (green), and
thyroxine (T4) (yellow)
What active hormones are produced by the thyroid? - ANSWER:triiodothyronine (T3) and thyroxine (T4,
tetraiodothyronine)
4 steps to synthesis of thyroid hormoness - ANSWER:1. Uptake
2. Activation (Oxidation by peroxidase)
3. Iodination of Tyrosine
4. Coupling of Iodinated Tyrosine
3 Principle Actions of Thyroid Hormones - ANSWER:(1) stimulation of energy use
(2) stimulation of the heart
(3) promotion of growth and development
Most sensitive method for diagnosing hypothyroidism - ANSWER:Serum TSH
Levothyroxine Dosage in adults - ANSWER:100-125ug for 70kg adult
ORAL
Older adults- start at 25-50ug daily
Levothyroxine dose in Myxedema Coma - ANSWER:200-500 ug once
INJECTION
Addition dose of 100-300 ug can be given a day later
Levothyroxine dose for Congenital Hypothyroidism - ANSWER:<3mo: 10-15mg/kg
3-5mo: 8-10mg/kg
6-11mo: 6-8mg/kg
1-5yrs: 5-6mg/kg
6-12 yrs: 4-5mg/kg
ORAL
,Dose DECREASES with age.
Dose adjusted to normalize TSH and free T4
Levothyroxine dose for simple goiter - ANSWER:100-200ug
ORAL
Baseline data for levothyroxine - ANSWER:Serum levels of TSH and free T4
What are thionamide drugs - ANSWER:For hyperthyroidism
ex. methimazole and propylthiouracil (PTU)
Suppresses synthesis of thyroid hormones
long term-hyperthyroidism
short-term- subtotal thyroidectomy or tx with radioactive iodine
Frequency of therapy for Methimazole and Propylthiouracil - ANSWER:Methimazole: Initial therapy-3
times a day
Maintenance therapy- Once a day
Propyltiouracil:
Initial therapy- 3 or 4 times a day
Maintenance therapy- 2 or 3 times a day
What is a first-line drug for hyperthyroidism - ANSWER:Methimazole (Tapazole)
Methimazole - ANSWER:inhibits thyroid hormone synthesis--> DOES NOT DESTROY EXISTING STORES OF
THYROID HORMONE
SAFER and more convenient than PTU and preferred more
EXCEPT in those who are pregnant or breastfeeding and those who are in thyrotoxic crisis
May take 3-12 weeks to produce euthyroid state
Baseline data for methimazole - ANSWER:Obtain serum levels of thyroid-stimulating hormone (TSH), free
triiodothyronine (T3), and free thyroxine (T4). Check baseline CBC and LFTs prior to initiation.
Radioactive Iodine in Graves Disease - ANSWER:Used to destroy thyroid tissue
want remission without complete destruction of gland
however delayed hypothyroidism due to excessive thyroid damage is frequent complication
, Radioactive Iodine - ANSWER:Destruction of thyroid tissue produced primarily by emission of beta
particles
Don't travel outside of thyroid
initial effects days to weeks, full effects develop 2-3 months
66% cured with single exposure, others 2-3 tx more
Don't give to very young, pregnancy or breastfeeding
Dosage dependent on thyroid sixe and rate of thyroidal iodine uptake
Graves- usual 4-10mCi
Nonradioactive Iodine: Lugo Solution - ANSWER:AKA "strong iodine solution"
5%elemental iodine and 10% potassium iodide
Mechanism of action for Nonradioactive Iodine - ANSWER:Paradoxical suppressant effect on the thyroid
1st- high conc. of iodide decrease iodine uptake by thyroid
2nd- high conc. of iodide inhibit thyroid hormone synthesis by suppressing both the iodination of
tyrosine and coupling of iodinated tyrosine residues
3rd- high con. of iodine inhibit release of thyroid hormone into blood
All 3 combine to decrease circulating levels of T3 and T4
not sustained indefinitely
Therapeutic use Nonradioactive iodine - ANSWER:prep for thyroidectomy
initial effect w/in 24 hours
peak effect in 10-15 days
usually methimazole then nonradioactive iodine
Usually given with PTY last 10 days before surgery
also in thyrotoxic crisus
Dosage and administration of nonradioactive iodine - ANSWER:5-7 drops 3 times daily for 10 days
immediately preceding surgery
mix with juice or some other beverage
