Pharm Exam 3 - Drugs for Thyroid Disorders
NCLEX QUETSION: A patient has been given instructions about levothyroxine (Synthroid). Which statement by the patient indicates understanding of these instructions? A) "I'll take this medication in the morning so as not to interfere with sleep." B) "I'll plan to double my dose if I gain more than 1 pound per day." C) "It is best to take the medication with food so I don't have any nausea." D) "I'll be glad when I don't have to take this medication in a few months."
A - "I'll take this medication in the morning so as not to interfere with my sleep" Levothyroxine is used to treat hypothyroidism by increasing the basal metabolism and thus wakefulness. It is administered as a once-daily dose and is a lifelong therapy. It is best taken on an empty stomach to enhance absorption.
NCLEX QUESTION: Which manifestations should a nurse investigate first when monitoring a patient who is taking levothyroxine (Synthroid)? A) Tachycardia B) Tremors C) Insomnia D) Irritability
A - Tachycardia - High doses of levothyroxine may cause thyrotoxicosis, a condition of profound excessive thyroid activity. Tachycardia is the priority assessment, because it can lead to severe cardiac dysfunction. Tremors, insomnia, and irritability are other symptoms of thyrotoxicosis and should be assessed after tachycardia.
CASE STUDY: THYROID 4 - What med interactions would you anticiapte with initiation of thyroid hormone replacement therapy?
Absorption of levothyroxine can be reduced by SUCRALFATE and FERROUS SULFATE. SERTRALINE can accelerate levothyroxine metabolism. Report all of pts current meds so pharmacy and PCP can monitor and adjust serum levels of levothyroxine accordingly.
Name a blood disorder caused by thionamides
Agranulocytosis - may see sore throat or fever. (A blood disorder caused by thionamides)
NCLEX QUESTION: Which of these findings, if noted in a patient who is taking levothyroxine (Synthroid) and warfarin (Coumadin), would require follow-up by a nurse? A) Cardiac dysrhythmias B) Excessive bruising C) Weight loss of 5 kg D) Shortness of breath
B - Excessive bruising. Levothyroxine intensifies the effect of warfarin, an anticoagulant that increases the patient's risk for bleeding. The warfarin dose may need to be reduced. Cardiac dysrhythmias, weight loss, and shortness of breath are not effects associated with interactions of levothyroxine and warfarin.
NCLEX QUESTION: A nurse is planning care for a patient who has a nursing diagnosis of "Fatigue related to decreased triiodothyronine (T3), thyroxine (T4), and elevated thyroid-stimulating hormone (TSH) levels." The nurse associates the patient with which of these medical diagnoses? A) Thyrotoxicosis B) Hypothyroidism C) Hyperthyroidism D) Graves' disease
B - Hypothyroidism. The anterior pituitary increases production of TSH when thyroid hormone levels of T3 and T4, are reduced, reflecting primary hypothyroidism. Patients may experience fatigue caused by a lowered basal metabolic rate. Thyrotoxicosis, hyperthyroidism, and Graves' disease are medical conditions indicative of excessive thyroid activity.
NCLEX QUESTION: A nurse should consider which diagnostic test a priority to obtain before a patient receives iodine-131 (Iodotope)? A) White blood cell (WBC) count B) Electrocardiogram (ECG) C) Beta human chorionic gonadotropin (hCG) test D) Creatinine level
C - Beta human chorionic gonadotropin (hCG) - patient of reproductive age requires a negative result on a beta hCG (pregnancy hormone) test before iodine-131 can be administered. 131I is a radioactive isotope used to treat hyperthyroidism and is contraindicated in pregnancy and lactation. A WBC count, ECG, and creatinine level are not indicated before treatment with iodine-131.
NCLEX QUESTION: A patient with Graves' disease is treated with iodine-131 (Iodope) therapy. Which of these statements, if made by the patient, would indicate that the patient has the correct understanding of the treatment's effects? A) "I'll have to isolate myself from my family so I don't expose them to radiation." B) "I'm looking forward to feeling better immediately after this treatment." C) "I'll tell my doctor if I have fatigue, hair loss, or cold intolerance." D) "I'll need to take this drug on a daily basis for at least 1 year."
C - Report fatigue, hair loss, or cold intolerance - Iodine-131 usually is given as a single treatment to produce remission of Graves' disease. Fatigue, hair loss, and cold intolerance are signs of hypothyroidism, which is a complication of the treatment. Iodine-131 has a quick radioactive decay and half-life; therefore, isolation is not needed, but it can take up to 2 months for the desired response to develop.
CASE STUDY: THYROID 28 yr. old single mother complaining of lethargy, fatigue; being cold, tired; sudden loss of hair; difficulty communicating to hcp, repeating herself frequently. BP 120/68, HR 70, RR 12, T 97.8F. Face is pale, puffy, expressionless. Skin cold, dry, hair brittle. Enlarged thyroid gland. Current meds include sertraline (Zoloft) for depression, ferrous sulfacte for anemia, and sucralfate (Carafate) for peptic ulcer disease.
CASE STUDY QUESTIONS : THYROID 1 - What condition is most likely the cause of pt's complaints? Why? 2 - Which lab tests would you expect PCP to order? Why? 3 - PCP determines pt has hypothyroidism and orders pregnancy test despite pt's assurance that she is not pregnant. What is rationale? 4 - What med interactions would you anticiapte with initiation of thyroid hormone replacement therapy?
Discuss the effects of congenital hypothyroidism in infants
Congenital hypothyroidism in infants leads to: Mental retardation, large tongue, pot belly, dwarfish stature, derangement of growth - nerves, muscles, bone, teeth
NCLEX QUESTION: A patient with hyperthyroidism is taking propylthiouracil (PTU). The nurse will monitor the patient for: A) gingival hyperplasia and lycopenemia. B) dyspnea and a dry cough. C) blurred vision and nystagmus. D) fever and sore throat.
D - Fever and sore throat. Agranulocytosis (the absence of granulocytes to fight infection) is the most serious toxicity associated with propylthiouracil. Sore throat and fever may be the earliest signs. Nausea, muscle soreness, and headache and dizziness are other adverse effects of propylthiouracil that are not as serious as agranulocytosis.
What TSH level is expected with hyperthyroidism?
Decreased TSH is expected in hyperthyroidism
Which drugs can cause decreased absorption of levothyroxine? How many hours after the administration of levothyroxine may these drugs be given?
H2-receptor blockers, proton pump inhibitors, bile-acid sequestrants such as colestyramine (Questran) and colestipol (Colestid); sucralfate (Carafate); calcium, iron, magnesium, aluminum caused decreased absorption of levothyroxine. Levothyroxine may be given 4 hours after these drugs.
At what heart rate would the nurse hold the levothyroxine and call the perscriber?
Hold levothyroxine and call perscriber c HR > 100/min
CASE STUDY: THYROID 1 - What condition is most likely the cause of pt's complaints? Why?
Hypothyroidism. Her symptoms fit the clinical presentation, however, appropriate lab tests should be conducted to confirm this.
How does an iodine solution work?
Iodine solution inhibits synthesis and release of thyroid hormones
Why might liothyroninr (Cytomel) be given instead of levothyroxine (Levothyroid)?
Levothyroxine (Levothyroid) can cause rapid onset of action in myxedema coma - Liothyroninr (Cytomel) may be given instead
What is the interaction between catecholamines and levothyroxine?
Levothyroxine increases the body's response to epinephrine, norepinephrine, and dopamine (catecholamines)
Why would a nurse administer levothyroxine with caution to a patient on warfarin?
Levothyroxine increases the degradation of Vitamin K-dependent clotting factors and may increase the chance of bleeding. May need to decrease dose of warfarin.
How long until levothyroxine reaches a plateau?
Levothyroxine reaches plateau after one month
Levothyroxine should be given with or without food?
Levothyroxine should be given without food
Describe the relationship of TSH levels to T3 and T4 levels
Low T3 or T4 increases TSH. High T3 or T4 lowers TSH
LOW-dose iodine-131 causes which delayed adverse effect?
Low-dose iodine-131 causes HYPOTHYROIDISM
CASE STUDY: THYROID 3 - PCP determines pt has hypothyroidism and orders pregnancy test despite pt's assurance that she is not pregnant. What is rationale?
Maternal hypothyroidism can result in permanent neuropsychological defects in fetus. Impact is limited largely to first trimester, when fetus is unable to produce it's own thyroid hormones. Therefore, maternal hypothyroidism should be diagnosed and treated very early to prevent complications.
Discuss the effects on the fetus of maternal hypothyroidism in pregnancy. A person treated for hypothyroidism may need to increase the does of levothyroxine by how much?
Maternal hypothyroidism leads to decreased IQ and neuropsychological function of the fetus. Increase maternal dose of levothyroxine dose by up to 50%. Increase by 30% as soon as pregnancy confirmed.
Labs to monitor for thyroid disorders
Monitor: - T3 - T4 - TSH
Discuss the nursing care of a patient with hypothyroidism
Nursing care for patient with hypothyroidism includes: Life-long replacement; take on an empty stomach; monitor for hypothyroidism and hyperthyroidism; hold levothyroxine if pulse > 100/min and capp primary care provider; monitor TSH, T3, and T4; minimize adverse drug interactions; monitor warfarin levels.
Persons over 50 years of age may need what change in the initial dose of levothyroxine?
Over 50 may need a lowered initial dose of levothyroxine
Give two ways a propyithiouracil (PTU) works in hyperthyroidism
PTU in hyperthyroidism: 1 - Inhibits thyroid hormone synthesis by inhibiting peroxidase 2 - Suppresses conversion of T4 to T3 in the periphery
What precautions should be taken with persons undergoing HIGH-dose iodine-131?
Precautions for patients undergoing high dose iodine-131: -Stay 3-6ft from patient -30 mins of contact/day -Double flush urine and secretions -Have patient increase fluids and void frequently
Describe common clinical signs and symptoms of hypothyroidism
S/S of hypothyroidism: Goiter; puffy, expressionless face; cold/dry skin; brittle hair; hair loss from scalp and outer half of eyebrows; fatigue; irritability; depression; lack of concentration; cold intolerance; constipation; heavy menses; increased cholesterol
Describe the signs and symptoms of thyrotoxicosis
S/S of thyrotoxicosis: Tachycardia, angina, tremor, nervousness, incomnia, hyperthermia, heat intolerance, sweating, weight loss, increased appetite
CASE STUDY: THYROID 2 - Which lab tests would you expect PCP to order? Why?
Serum T4 test will measure thyroxine - reflects overall thyroid activity and useful for initial screening of thyroid function (low in hypothyroidism). Serum TSH is most sensitive method for diagnosing hypothyroidism b/c small reductions in T3 and T4 cause a dramatic rise in serum TSH. Even minimal hypothyroidism is reflected with abnormally high TSH levels. T3 is not useful for diagnosing hypothyroidism.
What are some signs and symptoms of Grave's Disease?
Signs and symptoms of Graves' Disease: Rapid, strong heartbeat; rapid thoughts and speech; trouble concentrating; tremor; insomnia; weakened muscles; increased body temperature; warm moist skin; increased appetite with weight loss; diarrhea; exophthalamos
What are the symptoms of thyrotoxic crisis (thyroid storm)? What usually triggers it?
Symptoms of thyrotoxic crisis (thyroid storm): Restlessness, agitation, tremor, severe tachycardia, hypotension, heart failure, hyperthermia, profound weakness, unconsciousness, coma. Severe illness or major surgery.
Which thyroid hormone is more potent?
T3 is more potent
Which thyroid hormone is converted in the periphery?
T4 is converted to T3 in the periphery
Describe the steps of thyroid hormone regulation (TRH, TSH, T3, T4, negative feedback loop)
TRH from hypothalamus > TSH from anterior pituitary > T3 & T4 from thyroid > inhibit TSH from anterior pituitary
Discuss the expected change in TSH when patient is responding to levothyroxine
TSH decrease to normal levels - expected response to levothyroxine
How does Tapazole (methimazole) work differently from PTU?
Tapazole (methimazole) inhibits thyroid hormone synthesis, but does not block T4 or T3 in the periphery
What two hormones does the thyroid produce?
Thyroid produces: Triiodothyronine T3 Thyroxine T4
What mimics TSH in patients with Grave's Disease?
Thyroid-stimulating immunoglobins (TSI) mimics TSH in patients with Grave's Disease
What may happen to thyroid hormone production after the use of a thionamide?
Use of a thionamide can cause decreased thyroid hormone production (Hypothyroidism)