Pharmacology: Chapter 31: Thyroid and Antithyroid Drugs

When assessing for potential toxicity to PTU, the nurse will monitor the patient for changes in which laboratory test? 1CBC 2BNP 3Serum electrolytes 4Renal function tests

1 With antithyroid medications, the nurse should monitor for possible toxic reactions such as agranulocytosis, pancytopenia, and life-threatening hepatitis. An abnormal CBC would indicate bone marrow dysfunction.

11. The nurse is examining changes in a medication administration record after new orders were written. One new medication order reads, "levothyroxine (Levothroid), 200 mg, once a day." The nurse sus- pects an error. What is wrong with this order?

11. There are two errors. (1) Levothyroxine is dosed in micrograms. A common medication error is to write the intended dose in milligrams instead of micro- grams. If not caught, this error would result in a thousandfold overdose. Doses higher than 200 mcg must be questioned in case this error occurred. (2) The route is not written. This drug would be admin- istered PO. (Lilley, 122012)

12. Rory, age 32, has been given a prescription for pro- pylthiouracil (PTU) as part of treatment for Graves' disease. What laboratory tests are important to assess before she begins this medication? (Lilley, 122012)

12. The most damaging or serious adverse effects of pro- pylthiouracil (PTU) medications are liver and bone marrow toxicity. Therefore, it is important to assess liver function studies as well as a complete blood count (white blood cells, red blood cells, platelets). (Lilley, 122012)

Patients taking levothyroxine (Synthroid) and warfarin (Coumadin) concurrently would be monitored for which adverse effect? 1Cardiac arrhythmias 2Increased risk of bleeding 3Excessive weight loss 4Increased risk of deep vein thrombosis

2 Levothyroxine can compete with protein-binding sites of warfarin, allowing more warfarin to be unbound or free, thus increasing effects of warfarin and risk of bleeding.

The nurse is teaching the patient taking an antithyroid medication to avoid foods high in iodine. Which food will the nurse advise the patient against? 1Milk 2Eggs 3Seafood 4Chicken

3 Seafood contains high amounts of iodine. The other choices do not.

9. A patient, newly diagnosed with hypothyroidism, has received a prescription for thyroid replacement therapy. The nurse will instruct the patient to take this medication at which time of day? a. In the morning b. With the noon meal c. With the evening meal d. At bedtime

ANS: A If possible, it is best to administer thyroid drugs taken once daily in the morning so as to decrease the likelihood of insomnia that may result from evening dosing. DIF: COGNITIVE LEVEL: Applying (Application) REF: p. 507 TOP: NURSING PROCESS: Implementation MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

10. When reviewing the laboratory values of a patient who is taking antithyroid drugs, the nurse will monitor for which adverse effect? a. Decreased glucose levels b. Decreased white blood cell count c. Increased red blood cell count d. Increased platelet count

ANS: B Antithyroid drugs may cause bone marrow suppression, resulting in agranulocytosis, leukopenia, thrombocytopenia, and other problems. The other options are incorrect. DIF: COGNITIVE LEVEL: Applying (Application) REF: p. 505 TOP: NURSING PROCESS: Evaluation MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

6. A 19-year-old student was diagnosed with hypothyroidism and has started thyroid replacement therapy with levothyroxine (Synthroid). After 1 week, she called the clinic to report that she does not feel better. Which response from the nurse is correct? a. "It will probably require surgery for a cure to happen." b. "The full therapeutic effects may not occur for 3 to 4 weeks." c. "Is it possible that you did not take your medication as instructed?" d. "Let's review your diet; it may be causing absorption problems."

ANS: B Patients need to understand that it may take up to 3 to 4 weeks to see the full therapeutic effects of thyroid drugs. The other options are incorrect. DIF: COGNITIVE LEVEL: Applying (Application) REF: p. 508 TOP: NURSING PROCESS: Evaluation MSC: NCLEX: Physiological Integrity: Physiological Adaptation

4. During a teaching session for a patient on antithyroid drugs, the nurse will discuss which dietary instructions? a. Using iodized salt when cooking b. Avoiding foods containing iodine c. Restricting fluid intake to 2500 mL per day d. Increasing intake of sodium- and potassium-containing foods

ANS: B Patients on antithyroid therapy need to avoid iodine-containing foods. These foods may interfere with the effectiveness of the antithyroid drug. The other options are incorrect. DIF: COGNITIVE LEVEL: Applying (Application) REF: p. 508 TOP: NURSING PROCESS: Implementation MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

5. A patient who is taking propylthiouracil (PTU) for hyperthyroidism wants to know how this medicine works. Which explanation by the nurse is accurate? a. It blocks the action of thyroid hormone. b. It slows down the formation of thyroid hormone. c. It destroys overactive cells in the thyroid gland. d. It inactivates already existing thyroid hormone in the bloodstream.

ANS: B Propylthiouracil impedes the formation of thyroid hormone but has no effect on already existing thyroid hormone. The other options are incorrect. DIF: COGNITIVE LEVEL: Understanding (Comprehension) REF: p. 505 TOP: NURSING PROCESS: Implementation MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

8. When monitoring a patient who is taking a thyroid replacement hormone, which adverse effect needs to be reported to the prescriber? a. Weakness b. Palpitations c. Constipation d. Drowsiness

ANS: B The signs of excess dosages of thyroid replacement hormone mimic those of hyperthyroidism. Instruct the patient to report immediately any of the following to the prescriber: chest pain, weight loss, palpitations, tremors, sweating, nervousness, shortness of breath, or insomnia. The other options are incorrect. DIF: COGNITIVE LEVEL: Applying (Application) REF: p. 508 TOP: NURSING PROCESS: Assessment MSC: NCLEX: Safe and Effective Care Environment: Safety and Infection Control

1. Levothyroxine (Synthroid) has been prescribed for a patient with hypothyroidism. The nurse provides information to the patient about the medication and tells the patient to contact the prescriber if which potential adverse effect occurs? (Select all that apply.) a. Fatigue b. Chest pains c. Palpitations d. Drowsiness e. Rapid heart rate f. Constipation

ANS: B, C, E Some of the more serious adverse effects of the thyroid drugs include tachycardia, palpitations, and chest pains. The other options are not adverse effects of thyroid replacement drugs. DIF: COGNITIVE LEVEL: Applying (Application) REF: p. 508 TOP: NURSING PROCESS: Planning MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

7. When reviewing the drugs taken by a patient who will be starting thyroid replacement preparations, the nurse notes that an interaction may occur with which of these drugs? a. Vitamin supplements b. Antibiotics c. Oral antidiabetic drugs d. Beta blockers

ANS: C Drug interactions with thyroid replacement preparations include oral antidiabetic drugs, anticoagulants, cholestyramine, and digitalis. See Table 31-3. DIF: COGNITIVE LEVEL: Understanding (Comprehension) REF: p. 503 TOP: NURSING PROCESS: Assessment MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

12. A patient has a diagnosis of primary hypothyroidism. Which statement accurately describes this problem? a. The hypothalamus is not secreting thyrotropin-releasing hormone (TRH), therefore thyroid-stimulating hormone (TSH) is not released from the pituitary gland. b. The pituitary gland is dysfunctional and is not secreting TSH. c. The abnormality is in the thyroid gland itself. d. The abnormality is caused by an insufficient intake of iodine.

ANS: C Primary hypothyroidism stems from an abnormality in the thyroid gland itself and occurs when the thyroid gland is not able to perform one of its many functions. Secondary hypothyroidism begins at the level of the pituitary gland and results from reduced secretion of TSH. TSH is needed to trigger the release of the T3 and T4 stored in the thyroid gland. Tertiary hypothyroidism is caused by a reduced level of the TRH from the hypothalamus. This reduced level, in turn, reduces TSH and thyroid hormone levels. DIF: COGNITIVE LEVEL: Understanding (Comprehension) REF: p. 502 TOP: NURSING PROCESS: Assessment MSC: NCLEX: Physiological Integrity: Physiological Adaptation

1. A patient, newly diagnosed with hypothyroidism, receives a prescription for a thyroid hormone replacement drug. The nurse assesses for which potential contraindication to this drug? a. Infection b. Diabetes mellitus c. Liver disease d. Recent myocardial infarction

ANS: D Contraindications to thyroid preparations include known drug allergy to a given drug product, recent myocardial infarction, adrenal insufficiency, and hyperthyroidism. The other options are incorrect. DIF: COGNITIVE LEVEL: Understanding (Comprehension) REF: p. 503 TOP: NURSING PROCESS: Assessment MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

3. The order reads, "Give levothyroxine (Synthroid), 200 mg, PO once every morning." Which action by the nurse is correct? a. Give the medication as ordered. b. Change the dose to 200 mcg, because that is what the prescriber meant. c. Hold the drug until the prescriber returns to see the patient. d. Question the order because the dose is higher than 200 mcg.

ANS: D Levothyroxine is dosed in micrograms. A common medication error is to write the intended dose in milligrams instead of micrograms. If not caught, this error would result in a thousandfold overdose. Doses higher than 200 mcg need to be questioned in case this error has occurred. The other options are incorrect. DIF: COGNITIVE LEVEL: Analyzing (Analysis) REF: p. 504 TOP: NURSING PROCESS: Planning MSC: NCLEX: Safe and Effective Care Environment: Safety and Infection Control

2. A patient with hypothyroidism is given a prescription for levothyroxine (Synthroid). When the nurse explains that this is a synthetic form of the thyroid hormone, he states that he prefers to receive more "natural" forms of drugs. What will the nurse explain to him about the advantages of levothyroxine? a. It has a stronger effect than the natural forms. b. Levothyroxine is less expensive than the natural forms. c. The synthetic form has fewer adverse effects on the gastrointestinal tract. d. The half-life of levothyroxine is long enough to permit once-daily dosing.

ANS: D One advantage of levothyroxine over the natural forms is that it can be administered only once a day because of its long half-life. The other options are incorrect. DIF: COGNITIVE LEVEL: Applying (Application) REF: p. 504 TOP: NURSING PROCESS: Implementation MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

11. A patient has been taking levothyroxine (Synthroid) for more than 1 decade for primary hypothyroidism. Today she calls because she has a cousin who can get her the same medication in a generic form from a pharmaceutical supply company. Which is the nurse's best advice? a. "This would be a great way to save money." b. "There's no difference in brands of this medication." c. "This should never be done; once you start with a certain brand, you must stay with it." d. "It's better not to switch brands unless we check with your doctor."

ANS: D Switching brands of levothyroxine during treatment can destabilize the course of treatment. Thyroid function test results need to be monitored more carefully when switching products. DIF: COGNITIVE LEVEL: Analyzing (Analysis) REF: p. 504 TOP: NURSING PROCESS: Implementation MSC: NCLEX: Physiological Integrity: Pharmacological and Parenteral Therapies

13. A 19-year-old woman has been diagnosed with hypothyroidism and has started thyroid replacement therapy with levothyroxine (Synthroid). After 6 months, she calls the nurse to say that she feels better and wants to stop the medication. Which response by the nurse is correct? a. "You can stop the medication if your symptoms have improved." b. "You need to stay on the medication for at least 1 year before a decision about stopping it can be made." c. "You need to stay on this medication until you become pregnant." d. "Medication therapy for hypothyroidism is usually lifelong, and you should not stop taking the medication."

ANS: D These medications must never be abruptly discontinued, and lifelong therapy is usually the norm. The other options are incorrect. DIF: COGNITIVE LEVEL: Applying (Application) REF: p. 508 TOP: NURSING PROCESS: Assessment MSC: NCLEX: Physiological Integrity: Physiological Adaptation

6 When teaching a patient who has a new prescription for thyroid hormone, the nurse will instruct the patient to notify the physician if which adverse effects are noted? (Select all that apply.) a Palpitations b Weight gain c Angina d Fatigue e Cold intoleranc

a,c

4. Which information needs to be included in the nurse's teaching of patients taking thyroid medications? (Select all that apply.) a. Keeping a log or journal of individual responses and a graph of pulse rate, weight, and mood would be helpful. b. The medication will be discontinued if the adverse effects become too strong. c. The medication needs to be taken at the same time every day. d. Nervousness, irritability, and insomnia may be a result of a dosage that is too high. e. Take thyroid replacement drugs after meals.

a,c,d

1 When monitoring the laboratory values of a patient who is taking antithyroid drugs, the nurse knows to watch for a increased platelet counts. b decreased white blood cell counts. c decreased blood urea nitrogen level. d increased blood glucose levels.

b

5 The nurse is teaching a patient who has a new prescription for the antithyroid drug propylthiouracil (PTU). Which statement by the nurse is correct? a "There are no food restrictions while on this drug." b "You need to avoid foods high in iodine, such as iodized salt, seafood, and soy products." c "This drug is given to raise the thyroid hormone levels in your blood." d "Take this drug in the morning on an empty stomach."

b

6. The nurse has been providing patient education regarding thyroid hormone replacement therapy. Which statement by the patient reflects a need for further teaching? a. "I will take this pill in the mornings." b. "Sometimes this medicine can make my heart skip beats, but that's a normal side effect." c. "I need to take this pill on an empty stomach, and wait about 30 to 60 minutes before eating." d. "I will be sure to go to the clinic to have my thyroid levels tested regularly." (Lilley, 122012)

b

1. A patient who is beginning therapy with levothyrox- ine (Synthroid) asks the nurse when the medication will start working. What is the nurse's best answer? a. Immediately b.Within a few days c.Within a few weeks d.Within a few months

c

4 To help with the insomnia associated with thyroid hormone replacement therapy, the nurse will teach the patient to a take half the dose at lunchtime and the other half 2 hours later. b use a sedative to assist with falling asleep. c take the dose upon awakening in the morning. d reduce the dosage as needed if sleep is impaired.

c

5. A patient is scheduled for a radioactive isotope study. The scheduling nurse notes that he takes levothyroxine (Levothroid) daily. Which medication or- der needs to be made before the radioactive isotope study is scheduled? a. Continue to take the levothyroxine as ordered. b. Do not take the levothyroxine on the morning of the test. c. Stop the levothyroxine about 4 weeks before the test. d. Reduce the levothyroxine dosage by one-half 1 week before the test.

c

2 The pharmacy has called a patient to notify her that the current brand of thyroid replacement hormone is on back order. The patient calls the clinic to ask what to do. Which is the best response by the nurse? a "Go ahead and take the other brand that the pharmacy has available for now." b "You can stop the medication until your current brand is available." c "You can split the thyroid pills that you have left so that they will last longer." d "Let me ask your physician what needs to be done; we will need to watch how you do if you switch brands."

d

2. A patient wants to switch brands of levothyroxine (Synthroid). What is the nurse's best response? a. "If you do this, you should reduce the dosage of your current brand before starting the new one." b. "Levothyroxine has been standardized, so there is only one brand." c. "It shouldn't matter if you switch brands; they are all very much the same." d. "You should check with your provider before switching brands."

d

3 When assessing the elderly patient, the nurse keeps in mind that certain nonspecific symptoms may represent hypothyroidism in these patients, such as: a leukopenia, anemia b loss of appetite, polyuria c weight loss, dry cough d cold intolerance, depression

d

Which statement by the patient demonstrates an understanding of discharge instructions on the use of levothyroxine (Synthroid)? 1"I will take this medication in the morning so as not to interfere with sleep." 2"I will double my dose if I gain more than 1 pound per day." 3"I will stop the medication immediately if I lose more than 2 pounds in a week." 4"I can expect to see relief of my symptoms within 1 week."

1 I will take this medication in the morning so as not to interfere with sleep." Levothyroxine increases basal metabolism and thus wakefulness. Patients should not double the dose or stop taking the medication abruptly. It may take up to 4 weeks for a therapeutic response to occur.

The nurse would suspect excessive thyroid replacement in a patient taking levothyroxine (Synthroid) when the patient is exhibiting which adverse effect? 1Depression 2Intolerance to cold 3Weight gain 4Irritability

1 Irritability is a symptom of hyperthyroidism. The other choices are signs of hypothyroidism.

The nurse is reviewing adverse effects of antithyroid medications with a patient who has been taking PTU. What adverse effects does the nurse include in the teaching? Select all that apply. 1 Liver toxicity 2Polyuria 3Kidney damage 4Bone marrow toxicity 5Joint pain

1,4,5 The most damaging or serious adverse effects of the antithyroid medications are liver and bone marrow toxicity. Myalgias and arthralgias (joint pain) may also occur with PTU

10. After undergoing a thyroidectomy as treatment for a thyroid tumor that turned out to be benign, Rebecca is given a prescription for levothyroxine (Levothroid). "I thought I would be cured after this surgery!" she exclaimed. "Why do I have to take a pill every day?" What will the nurse explain to Rebecca?

10. Surgery to remove all or part of the thyroid gland is an effective way to treat hyperthyroidism, but as a result, lifelong hormone replacement is normally required. (Lilley, 122012)

A patient receiving propylthiouracil (PTU) asks the nurse how this medication will help relieve his symptoms. What is the nurse's best response? 1"Propylthiouracil inactivates any circulating thyroid hormone, thus decreasing signs and symptoms of hyperthyroidism." 2"Propylthiouracil inhibits the formation of new thyroid hormone, thus gradually returning your metabolism to normal." 3"Propylthiouracil helps your thyroid gland use iodine and synthesize hormones better." 4"Propylthiouracil stimulates the pituitary gland to secrete thyroid-stimulating hormone (TSH), which inhibits the production of hormones by the thyroid gland."

2 "Propylthiouracil inhibits the formation of new thyroid hormone, thus gradually returning your metabolism to normal." Propylthiouracil is an antithyroid medication used to treat hyperthyroidism. It works by inhibiting the synthesis of new thyroid hormone. It does not inactivate present hormone.

Which patient statement demonstrates understanding of radioactive iodine (I-131) therapy? 1"I will have to isolate myself from my family for 1 week so as not to expose them to radiation." 2"This drug will be taken up by the thyroid gland and destroy the cells to reduce my hyperthyroidism." 3"This drug will help decrease my cold intolerance and weight gain." 4"I will need to take this drug on a daily basis for at least 1 year."

2 "This drug will be taken up by the thyroid gland and destroy the cells to reduce my hyperthyroidism." Radioactive iodine is an antithyroid medication that is administered orally for one or two doses only. It concentrates in the thyroid gland, enabling the radiation to destroy the hyperplastic cells.

3. Patient teaching for a patient taking antithyroid med- ication will include the need to avoid which foods? a. Soy products and seafood b. Bananas and oranges c. Dairy products d. Processed meats and cheese

a

9. Mrs. W., age 43, comes into the clinic complaining of hair loss, lethargy, and constipation. "I just can't eat anything," she says. As the nurse takes her blood pressure, he notices that her skin feels thickened. She also seems to have a lump in her neck. The primary care provider makes a diagnosis of hypothyroidism. Suggest several possible appropriate medications. Which of those is generally preferred? Why?

9. Mrs. W. probably has hypothyroidism, which may result in the formation of a goiter, an enlargement of the thyroid gland resulting from its overstimulation by elevated levels of thyroid-stimulating hormone. She may benefit from one of the thyroid drugs, including thyroid, levothyroxine, liothyronine, or liotrix. Levothyroxine is generally preferred because, as a chemically pure formulation of 100% thyroxine, its hormonal content is standardized; therefore, its effect is predictable. (Lilley, 122012)