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Pharm Exam 3 Ch 47

Terms in this set (48)

what is the generic name for T3
liothyronine
what is the generic name for T4
levothyroxine
What is the name for the fixed ratio mixture of T3 and T4
liotrix
T3 and T4 have slow metabolism due to what?
extensive binding to plasma proteins
what is the half-life of T3 and T4?
T3- 1 day
T4- 7 days
True or False: thyroid hormones produce effects by modulating the activity of specific genes
true
regulation of thyroid function is by what two brain structures
hypothalamus and anterior pituitary
Drop in thyroid hormone levels promotes TSH release-->acts on thyroid to do what?
increase size causing goiter
what is used primarily for screening and diagnosis of hypothyroidism and monitoring replacement therapy in hypothyroid patients
Serum TSH test
true or false: anterior pituitary is extremely sensitive to changes in thyroid hormone levels
true-very small reductions in serum T3 and T4 can cause dramatic rise in TSH
Primary hypothyroidism has ___ TSH levels; secondary hypothyroidism has ___ , __ , ____ TSH (even with low levels of T3 and T4
high
low, normal, or slightly elevated
what test is used to monitor replacement therapy and screen for thyroid dysfunction
serum thyroxine test (T4)
this is total T4 or free T4 (free T4 is preferred)
what test is used to diagnose hyperthyroidism
serum triiodothyronine test (T3)
this is total T3 or free T3 (free T3 is preferred)
what test is also used to monitor replacement therapy (all thyroid preparations should increase T3 levels)
serum triiodothyronine test (T3)
what is the therapeutic strategy for hypothyroidism
replacement therapy with thyroid hormones-must continue lifelong therapy in almost all cases
what is the clinical presentation of hypothyroidism in infants
large and protruding tongue
potbelly
dwarfish stature
development of what is impaired in infancy hypothyroidism
nervous system
bones
teeth
muscles
In infancy hypothyroidism replacement therapy should be continues or 3 years then stopped for ___ weeks to see if thyroid deficiency is permanent or _____
4 weeks
transient
what is the most common cause of excessive thyroid hormone secretion
grave's disease
true or false: incidence in males is 6x greater than females for graves disease
false- incidence in females is 6x greater than males
if there are signs and symptoms above hyperthyroidism what is this called
thyrotoxicosis
what is the name of the antibody that causes the autoimmune process in graves disease
thyroid stimulating immunoglobulins
true or false: thyroid stimulation immunoglobulins are not responsible for exophthalmos
true
what are these treatments for:
-directed at decreasing the production of thyroid hormones
-surgical removal of thyroid tissue
-beta blockers and nonradioactive iodine
hyperthyroidism
what can not be improve by lowering thyroid hormone production and if severe can be treated with surgery or high doses of oral glucocorticoids
exophthalmos
what is the result of thyroid adenoma and has clinical manifestations similar to Grave's disease except no exophthalmos
toxic nodular goiter (plummer disease)
true or false: treatment for toxic nodular goiter is the same as graves disease
true
what can occur in patients with sever thyrotoxicosis when undergoing major surgery or developing a severe intercurrent illness
thyrotoxic crisis (thyroid storm)
how is thyrotoxic crisis (thyroid storm) treated?
high doses of potassium iodide or strong iodine solution (suppresses thyroid hormone release)
What is the synthetic preparation of thyroxine
levothyroxine
which drug is reduced by food and should be taken on empty stomach in the morning 30-60 min before breakfast?
levothyroxine
what is the half life of levothyroxine
since it is highly protein bound it has prolonged half-life of 7 days
what drug is used to treat all forms of hypothyroidism regardless of cause
levothyroxine
which drug's adverse effects are these:
-acute overdoes; thyrotoxicosis
-tachycardia, angina, tremor, nervousness, insomnia, sweating, heat intolerance
-chronic overdosage associated with bone loss and increased risk for a-fib
levothyroxine
these drugs accelerate the metabolism of what drug?
-phenytoin
-rifampin
-carbamazepine
-sertraline
-phenobarbital
levothyroxine
when taking this drug warfarin may need to be reduced due to T4 acceleration of degradation of vitamin K-dependent clotting factors
levothyroxine
what are the 2 routes for levothyroxine
oral or IV
iv- used for myxedema coma and for pt's unable to take orally (doses are usually half the oral dose)
What is an antithyroid drug
thionamides
what is the first line drug of hyperthyroidism
methimazole
this is the MOA for what drug: block synthesis of thyroid hormones (prevents oxidation of iodide) and does not destroy existing stores of thyroid hormone
methimazole
what is the drug that has these therapeutic uses:
-sole form of therapy for graves disease
-adjunct radiation therapy
-suppress thyroid hormone synthesis
-patients experiencing thyrotoxic crisis
methimazole
these are adverse effects for what drug:
-avoid by pregnant or breastfeeding women
-can cause neonatal hypothyroidism, goiter, or congenital hypothyroidism
-Agranulocytosis
-hypothyroidism
methimazole
what is radioactive isotope of stable iodine that emits a combo of beta particles and gamma rays
iodine-131
radioactive decay takes place rapidly-half life of __ days
8
radioactive iodine is used in what disease treatment
graves
what can be used to destroy thyroid tissue in patients with hyperthyroidism
radioactive iodine
true or false: about 66% of patients are cured with a single exposure to iodine-131, others need 2-3 treatments
true
what treatment has relative low cost, pt is spared risk-discomfort-and expense of thyroid surgery, no tissue other than the thyroid is injured
radioactive iodine
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