Pharmacology: Chapter 58

Which statement is the most important for a nurse to make to a patient who is taking methimazole? A) "You need to notify your doctor if you have a sore throat and fever." B) "Another medication can be given if you experience any nausea." C) "You may experience some muscle soreness with this medicine." D) "Headache and dizziness may occur but not very frequently."

ANS: A Agranulocytosis (the absence of granulocytes to fight infection) is the most serious toxicity associated with methimazole. Sore throat and fever may be the earliest signs. Nausea, muscle soreness, and headache and dizziness are other adverse effects of methimazole that are not as serious as agranulocytosis.

Which manifestations should a nurse investigate *first* when monitoring a patient who is taking levothyroxine (Synthroid)? A) Tachycardia B) Tremors C) Insomnia D) Irritability

ANS: A 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.

A 1-year-old child with cretinism has been receiving 8 mcg/kg/day of levothyroxine [Synthroid]. The child comes to the clinic for a well-child checkup. The nurse will expect the provider to: a. change the dose of levothyroxine to 6 mcg/kg/day. b. discontinue the drug if the child's physical and mental development are normal. c. increase the dose to accommodate the child's increased growth. d. stop the drug for 4 weeks and check the child's TSH level.

ANS: A In the treatment of cretinism, thyroid dosing decreases with age. For infants 6 to 12 months of age, the dose is 6 mcg/kg/day. At 1 year of age, the dose is reduced to 5 to 6 mcg/kg/day. For all children, treatment should continue for 3 years. It is incorrect to increase the dose with age. After 3 years of therapy, the patient undergoes a trial of 4 weeks without the drug, followed by assessment of the TSH and T4 levels, to determine whether the drug may be discontinued.

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."

ANS: A 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.

A patient has been taking levothyroxine for several years and reports that "for the past 2 weeks, the drug doesn't seem to work as well as before." What will the nurse do? a. Ask the patient when the prescription was last refilled. b. Expect the patient to have an elevated temperature and tachycardia. c. Suggest that the patient begin taking calcium supplements. d. Tell the patient to try taking the medication with food.

ANS: A Not all levothyroxine preparations have the same drug bioavailability; therefore, if a patient is experiencing differing effects, the pharmacist may have switched brands. Asking a patient about a recent refill may help to explain why the drug has different effects. An elevated temperature and tachycardia would be signs of toxicity, not of a decrease in effectiveness. Calcium supplements and food would only interfere with absorption and further reduce the drug's effectiveness.

A nurse is teaching a patient who will begin taking methimazole [Tapazole] for Graves' disease about the medication. Which statement by the patient indicates understanding of the teaching? a. "Because of the risk for liver toxicity, I will need frequent liver function tests." b. "I should report a sore throat or fever to my provider if either occurs." c. "I will need a complete blood count every few months." d. "It is safe to get pregnant while taking this medication."

ANS: B Agranulocytosis is rare but can occur with methimazole, so patients should report signs of infection, such as a sore throat or fever. Liver toxicity is not a side effect, so liver function tests are not indicated. Because agranulocytosis often develops rapidly, periodic blood counts do not guarantee early detection. Methimazole is contraindicated in the first trimester of pregnancy.

The nurse prepares a patient with Graves' disease for radioactive iodine (131I) therapy. Which statement made by the patient best demonstrates understanding of 131I therapy? a. "I will have to isolate myself from my family for 1 week so that I don't expose them to radiation." b. "This drug will be taken up by the thyroid gland and will destroy the cells to reduce my hyperthyroidism." c. "This drug will help reduce my cold intolerance and weight gain." d. "I will need to take this drug on a daily basis for at least 1 year."

ANS: B Iodine-131 can be used to destroy thyroid tissue in patients with hyperthyroidism; no further teaching is necessary. The patient does not need to isolate himself from others. The treatment will not reduce intolerance to cold, nor will it affect weight gain. The patient will not need the treatment daily.

A patient is admitted to the hospital and will begin taking levothyroxine [Synthroid]. The nurse learns that the patient also takes warfarin [Coumadin]. The nurse will notify the provider to discuss ____ the ____ dose. a. reducing; levothyroxine b. reducing; warfarin c. increasing; levothyroxine d. increasing; warfarin

ANS: B Levothyroxine accelerates the degradation of vitamin K-dependent clotting factors, which enhances the effects of warfarin. Patients taking warfarin who start taking levothyroxine may need to have their warfarin dose reduced. It is not correct to increase or decrease the levothyroxine dose or to increase the warfarin dose.

Which finding in a patient 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

ANS: B Levothyroxine intensifies the effect of warfarin, an anticoagulant that increases the patient's risk for bleeding. The warfarin dose may need to be reduced. Bruising, weight loss, and shortness of breath are not effects associated with interactions of levothyroxine and warfarin.

The nurse is caring for a pregnant patient recently diagnosed with hypothyroidism. The patient tells the nurse she does not want to take medications while she is pregnant. What will the nurse explain to this patient? a. Hypothyroidism is a normal effect of pregnancy and usually is of no consequence. b. Neuropsychologic deficits in the fetus can occur if the condition is not treated. c. No danger to the fetus exists until the third trimester. d. Treatment is required only if the patient is experiencing symptoms.

ANS: B Maternal hypothyroidism can result in permanent neuropsychologic deficits in the child. Hypothyroidism is not a normal effect of pregnancy and is a serious condition that can affect both mother and fetus. The greatest danger to the fetus occurs in the first trimester, because the thyroid does not fully develop until the second trimester. Early identification is essential. Symptoms often are vague. Treatment should begin as soon as possible, or mental retardation and other developmental problems may occur.

A nurse is caring for a patient with decreased triiodothyronine (T3) and thyroxine (T4) and elevated thyroid-stimulating hormone (TSH) levels. The nurse knows the patient is likely suffering from what? A) Thyrotoxicosis B) Hypothyroidism C) Hyperthyroidism D) Graves' disease

ANS: B 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.

A nurse caring for a patient notes that the patient has a temperature of 104°F and a heart rate of 110 beats per minute. The patient's skin is warm and moist, and the patient complains that the room is too warm. The patient appears nervous and has protuberant eyes. The nurse will contact the provider to discuss: a. cretinism. b. Graves' disease. c. myxedema. d. Plummer's disease.

ANS: B The signs and symptoms in this patient are consistent with hyperthyroidism, and because the patient's eyes are protuberant, they also are consistent with Graves' disease. Cretinism is hypothyroidism in children. Myxedema is severe hypothyroidism. Plummer's disease is a hyperthyroidism condition without exophthalmos.

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

ANS: C Any female patient of reproductive age requires a negative result on a beta hCG (pregnancy hormone) test before iodine-131 (131I) 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.

A patient with hypothyroidism begins taking PO levothyroxine [Synthroid]. The nurse assesses the patient at the beginning of the shift and notes a heart rate of 62 beats per minute and a temperature of 97.2°F. The patient is lethargic and difficult to arouse. The nurse will contact the provider to request an order for which drug? a. Beta blocker b. Increased dose of PO levothyroxine c. Intravenous levothyroxine d. Methimazole [Tapazole]

ANS: C Intravenous administration of levothyroxine is used for myxedema coma. This patient is showing signs of severe hypothyroidism, or myxedema. A beta blocker is useful in patients who show signs of hyperthyroidism to minimize cardiac effects. Because the half-life of oral levothyroxine is so long, increasing the PO dose will not provide immediate relief of this patient's symptoms. Methimazole is used to treat hyperthyroidism.

A patient with Graves' disease is treated with iodine-131 (Iodope) therapy. Which statement by the patient would indicate 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."

ANS: C 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.

A patient in her twenties with Graves' disease who takes methimazole [Tapazole] tells a nurse that she is trying to conceive and asks about disease management during pregnancy. What will the nurse tell her? a. Methimazole is safe to take throughout pregnancy. b. Propylthiouracil should be taken throughout her pregnancy. c. The patient should discuss changing to propylthiouracil from now until her second trimester with her provider. d. The patient should discuss therapy with iodine-131 instead of medications with her provider.

ANS: C Methimazole is not safe during the first trimester of pregnancy, because it is associated with neonatal hypothyroidism, goiter, and cretinism; however, it is safe in the second and third trimesters. Propylthiouracil is recommended for pregnant patients only in the first trimester and during lactation only if a thionamide is absolutely necessary. Iodine-131 is used in women older than 30 years who have not responded to medication therapy and is contraindicated during pregnancy

A nurse obtaining an admission history on an adult patient notes that the patient has a heart rate of 62 beats per minute, a blood pressure of 105/62 mm Hg, and a temperature of 96.2°F. The patient appears pale and complains of always feeling cold and tired. The nurse will contact the provider to discuss tests for which condition? a. Cretinism b. Graves' disease c. Hypothyroidism d. Plummer's disease

ANS: C This patient is showing signs of hypothyroidism: a low heart rate, low temperature, pale skin, and feeling cold and tired. In adults, thyroid deficiency is called hypothyroidism. In children, thyroid deficiency is called cretinism. Graves' disease and Plummer's disease are conditions caused by thyroid excess.

A patient has a free T4 level of 0.6 ng/dL and a free T3 of 220 pg/dL. The patient asks the nurse what these laboratory values mean. How will the nurse respond? a. "These laboratory values indicate that you may have Graves' disease." b. "These results suggest you may have hyperthyroidism." c. "We will need to obtain a total T4 and a total T3 to tell for sure." d. "We will need to obtain a TSH level to better evaluate your diagnosis."

ANS: D A free T4 level of less than 0.9 ng/dL and a free T3 of less than 230 pg/dL are consistent with hypothyroidism, but measurement of the thyroid-stimulating hormone (TSH) level is necessary to distinguish primary hypothyroidism from secondary hypothyroidism. Total T3 and T4 levels are not as helpful as free T3 and T4 levels. These laboratory values indicate hypothyroidism, not hyperthyroid conditions such as Graves' disease.

An *older adult* patient is diagnosed with hypothyroidism. The initial free T4 level is 0.5 mg/dL, and the TSH level is 8 microunits/mL. The prescriber orders levothyroxine [Levothroid] 100 mcg/day PO. What will the nurse do? a. Administer the medication as ordered. b. Contact the provider to discuss giving the levothyroxine IV. c. Request an order to give desiccated thyroid (Armour Thyroid). d. Suggest that the provider lower the dose.

ANS: D In older adult patients, initial dosing of levothyroxine should start low and be increased gradually. A typical starting dose for an elderly patient is 25 to 50 mcg/day. It is not correct to administer the medication without questioning the provider. Unless the patient has signs of myxedema, there is no need to give the medication IV. Desiccated thyroid is no longer used except in patients who have been taking it long term.

A nurse is teaching a patient who has been diagnosed with hypothyroidism about levothyroxine [Synthroid]. Which statement by the patient indicates a need for further teaching? a. "I should not take heartburn medication without consulting my provider." b. "I should report insomnia, tremors, and an increased heart rate to my provider." c. "If I take a multivitamin with iron, I should take it 4 hours after the Synthroid." d. "If I take calcium supplements, I may need to decrease my dose of Synthroid."

ANS: D Patients taking calcium supplements should take these either 4 hours before or after taking levothyroxine, because they interfere with levothyroxine absorption. Many heartburn medications contain calcium, so patients should consult their provider before taking them. Insomnia, tremors, and tachycardia are signs of levothyroxine toxicity and should be reported. Iron also interferes with levothyroxine absorption, so dosing should be 4 hours apart.

A patient arrives in the emergency department with a heart rate of 128 beats per minute and a temperature of 105°F. The patient's skin feels hot and moist. The free T4 level is 4 ng/dL, the free T3 level is 685 pg/dL, and the TSH level is 0.1 microunits/mL. The nurse caring for this patient will expect to administer: a. intravenous levothyroxine. b. iodine-131 (131I). c. methimazole [Tapazole]. d. propylthiouracil (PTU).

ANS: D Propylthiouracil is used for patients experiencing thyroid storm, and this patient is showing signs of that condition. Levothyroxine is given IV for hypothyroidism. 131I is used in patients over age 30 who have not responded to other therapies. Methimazole is used long term to treat hyperthyroidism, but PTU is more useful for emergency treatment.