Chapter 41 - Antitubercular Drugs

The patient is to receive isoniazid (INH) 0.3 g daily. The medication is available as 100-mg tablets. How many tablets will the nurse administer per dose?

3 tablets

CASE STUDY George, a 73-year-old retired plant foreman, has been diagnosed with tuberculosis. Nursing assessment reveals a history of gout and diabetes. He also has a history of heavy drinking. 1. What considerations will the physician keep in mind when deciding on a first-line drug for George? 2. George tells you that he has been told that he has a "liver problem." His medical record mentions that he is a slow acetylator. How does this affect his therapy? 3. How will his history of "heavy drinking" affect his therapy? 4. You instruct George about taking vitamin B6 along with the isoniazid (INH) therapy. When he asks you why this is necessary, what will you tell him?

1. George's gout is a consideration; pyrazinamide can cause hyperuricemia, so gout or flare-ups of gout can occur in susceptible patients. His diabetes is a concern, too; ethambutol should be used cautiously in patients with diabetes. A baseline hearing test should be per-formed if streptomycin is considered because this drug may cause ototoxicity. In addition, liver function studies are needed because his heavy alcohol use may have caused liver damage. 2. An individual with a genetic deficiency of the liver enzymes that metabolize drugs can be classified as a "slow acetylator." When isoniazid is taken by slow acetylators, the drug accumulates because there are not enough of the enzymes to break down the isoni-azid. As a result, the dosage of isoniazid may need to be reduced. 3. Results of liver function studies should be assessed carefully before therapy is initiated because some drugs (isoniazid, pyrazinamide) are hepatotoxic. Liver function test results should be monitored closely during therapy as well. 4. Isoniazid can cause a pyridoxine (vitamin B6) deficiency. Patients should take pyridoxine as prescribed by the physician to prevent some of the neurologic effects of vitamin B6 deficiency, such as numbness and tingling of t

The patient has new orders for pyrazinamide, 30 mg/kg/day. The patient weighs 132 lb. How many milligrams will the patient receive per day? Is this dosage safe?

1800 mg; yes, the maximum dose is 2g (2000 mg)

Why would an eye examination be performed before instituting antitubercular therapy?

A thorough eye examination may be called for before therapy is initiated because ethambutol can cause a decrease in visual acuity resulting from optic neuri-tis, which is also a contraindication to the use of ethambutol. In addition, isoniazid may cause optic neuritis and visual disturbances.

A patient will be receiving long-term isoniazid (INH) therapy. What laboratory tests are most important for the nurse to monitor during therapy? a. Liver enzyme levels b. Hematocrit and hemoglobin level c. Creatinine level d. Platelet count

a

The nurse is explaining antitubercular therapy to a patient. The patient asks, "Why do I have to take so many different medications?" What is the nurse's best response? a. "It helps prevent the tuberculosis from becoming resistant to the drugs." b. "It makes sure that the disease is cured." c. "These medications will reduce symptoms immediately." d. "You will have fewer side effects."

a

The nurse would correctly identify the method of action of ethambutol as which of the following? a. Inhibiting protein synthesis b. Inhibiting mycobacterial ATP synthase c. Altering cell wall synthesis d. Unknown method of action

a

The nurse would be correct in identifying which findings as possible side effects of bedaquiline? (Select all that apply.) a. Headache b. Chest pain c. Nausea d. QT prolongation e. Paresthesias

a, b, c

Which teaching point is the priority when educating the patient beginning antitubercular therapy? (Select all that apply.) a. Take medications as ordered and at the same time every day. b. Take medications on an empty stomach. c. Monitor blood glucose daily. d. Increase intake of green leafy vegetables.

a, b, c

The nurse is reviewing the medication list of a patient who has been newly diagnosed with tuberculosis and will be taking rifampin. Which classes of drugs, if taken with rifampin, may cause increased metabolism? (Select all that apply.) a. Beta blockers b. Proton pump inhibitors c. Selective serotonin reuptake inhibitors d. Oral anticoagulants e. Oral antidiabetic drugs

a, d, e

Frannie is a homeless 68-year-old woman who lives in a shelter some of the time. She was diagnosed with tuberculosis at the community health clinic, and antitubercular therapy has been instituted. a. What patient education issues are of particular concern in Frannie's case? b. Frannie is staying at the shelter and seems to be handling her medication regimen well, but one day she comes by the clinic to tell the nurse that she is afraid the medication may be bad for her. "Whenever I go to the bathroom, everything is reddish-orange," she says. What do you suspect is going on, and what do you tell Frannie?

a. Frannie, similar to all patients taking antituber-cular drugs, needs to be compliant with the therapy regimen and keep her follow-up appointments. She should be reminded that she can spread the disease (during the initial period of the illness); she should wash her hands frequently and cover her mouth when coughing or sneezing. Frannie also needs adequate nutrition and rest. b. It is likely that Frannie is on rifampin therapy. She should be told that her urine, stool, saliva, sputum, sweat, and tears may become red-orange-brown in color and that this is an effect of rifampin therapy.

Diane, a 33-year-old proofreader, has been pre-scribed prophylactic isoniazid (INH) treatment. a. What laboratory studies should be performed before the start of therapy? Why? b. After Diane has taken isoniazid (INH) for 2 months, the physician significantly reduces her dosage of the drug. Why might that be?

a. Liver function studies should be performed because isoniazid can cause hepatic impairment. In addition, an eye examination is important because the drug may cause visual disturbances. b. Diane may be a slow acetylator. Acetylation, the process by which isoniazid is metabolized in the liver, requires certain enzymes to break down the isoniazid. In slow acetylators, who have a genetic deficiency of these enzymes, isoniazid accumu-lates. The dosage of isoniazid may need to be adjusted downward in these patients.

Mr. F. is on antitubercular therapy. During his first follow-up visit, he is evasive when the nurse asks him about his compliance with his therapy regimen. He does tell the nurse that he has been very busy lately, entertaining various clients "at everything from cocktail parties to big sit-down dinners." a. What issues will the nurse discuss with Mr. F.? b. Several weeks later, Mr. F. returns for another follow-up visit. On examination, the nurse sees no apparent signs of tuberculosis. How can Mr. F.'s therapeutic response be confirmed?

a. Mr. F. needs to know that his compliance with therapy is essential for achieving a cure. Although he is keeping his follow-up appointments, Mr. F. also needs to take his medication as ordered. He should be warned not to consume alcohol because the antitubercular drugs may cause liver toxicity, andheshouldbe encouraged totake care ofhimself by ensuring adequate nutrition, rest, and relaxation. b. The therapeutic response can be confirmed by results of laboratory studies (sputum culture and sensitivity tests) and chest radiographic findings.

Ms. I. is undergoing antitubercular therapy that includes streptomycin and rifampin. a. How is streptomycin administered? b. Ms. I. takes an oral contraceptive. Is that a concern given Ms. I.'s antitubercular therapy? Explain your answer.

a. Streptomycin isadministeredintramuscularly, deep into a large muscle mass, and the sites are rotated. b. Although it may not be a concern in terms of Ms. I.'s streptomycin therapy, oral contraceptives become ineffective when given with rifampin. If rifampin is part of her therapy, Ms. I. should switch to another form of birth control.

The nurse should include which information in the teaching plan for a patient who is taking isoniazid (INH)? a. Urine and saliva may be reddish-orange. b. Pyridoxine (vitamin B6) should be added to the regimen. c. Injection sites should be rotated daily. d. The medication should be taken w

b

A patient newly diagnosed with tuberculosis asks the nurse how long he will need to take "all this medicine." The nurse replies that drug therapy for active tuberculosis may need to last how long? a. 6 months b. 12 months c. 24 months d. A lifetime

c

The nurse would correctly identify the method of action of isoniazid (INH) as which of the following? a. Inhibiting protein synthesis b. Inhibiting mycobacterial ATP synthase c. Altering cell wall synthesis d. Unknown method of action

c