Antimycobacterial Agents: Drugs for Tuberculosis, Leprosy, and Mycobacterium avium Complex Infection Flashcards
A nurse is performing a physical assessment on a patient with tuberculosis who takes rifampin (Rifadin). What would be an expected finding?
a. Crystalluria
b. Myopathy
c. Peripheral neuropathy
d. Red-orange–tinged urine
D
Urine tinged red-orange is a normal finding associated with rifampin’s adverse effects. Peripheral neuropathy, myopathy, and crystalluria are not manifestations of adverse effects of rifampin.
A nurse is teaching a group of nursing students about the problems associated with the long-term therapy required to treat tuberculosis. Which statement by a student indicates a need for further teaching?
a. “Long-term therapy increases the emergence of drug-resistant organisms.”
b. “Long-term therapy increases the incidence of drug toxicities.”
c. “Long-term therapy increases the likelihood of reactivation of latent infection.”
d. “Long-term therapy results in decreased patient adherence to drug regimens.”
C
Long-term drug therapy is used to prevent reactivation of latent infection that can occur if drugs are withdrawn too soon. Long-term therapy can result in the emergence of drug-resistant organisms, leads to more drug toxicities and side effects, and reduces adherence.
A nurse reads a tuberculin skin test on a patient and notes a 6 to 7 mm area of induration. The patient is a young adult who has recently immigrated from a country with a high prevalence of tuberculosis. The patient has no other risk factors. The nurse will expect the provider to:
a. begin treating this patient with a two-drug regimen of isoniazid and rifampin.
b. order a chest radiograph and a sputum culture to assess for active tuberculosis.
c. order a nucleic acid amplification test of the patient’s sputum.
d. reassure the patient that this is not considered a positive test result.
D
This patient has a moderate risk of tuberculosis; the area of induration would have to be 10 mm or greater to be considered a positive skin test result. Without other clinical signs, there is no indication to treat this patient or to perform diagnostic testing, so a chest x-ray or sputum cultures are not recommended.
A patient is beginning treatment for active tuberculosis (TB) in a region with little drug-resistant TB. Which treatment regimen will be used initially?
a. Isoniazid and pyrazinamide
b. Isoniazid, pyrazinamide, and ethambutol
c. Rifampin, pyrazinamide, and ethambutol
d. Isoniazid, rifampin, pyrazinamide, and ethambutol
D
The induction phase of treatment for patients in a region without drug resistance is the same as for patients who are human immunodeficiency virus (HIV) negative or HIV positive and includes isoniazid, rifampin, pyrazinamide, and ethambutol. It is not correct to begin with two drugs. The three-drug regimen is used for inductions in areas with resistance to either isoniazid or rifampin.
A patient with HIV who takes protease inhibitors develops tuberculosis and will begin treatment. Which drug regimen will be used for this patient?
a. Isoniazid, pyrazinamide, ethambutol + rifabutin
b. Isoniazid, pyrazinamide, ethambutol
c. Isoniazid, rifampin, pyrazinamide, ethambutol
d. Isoniazid + rifabutin
A
Patients with HIV who take protease inhibitors are susceptible to drug interactions with rifampin, which accelerates the metabolism of protease inhibitors. Rifabutin can be substituted for rifampin in patients with HIV, because the degree of acceleration of this metabolism is less. A three-drug regimen would increase drug resistance, as would a two-drug regimen.
A patient newly diagnosed with tuberculosis asks the nurse why oral medications must be given in the clinic. The nurse will tell the patient that medications are given in the clinic so that:
a. clinic staff can observe adherence to drug regimens.
b. nurses can monitor for drug toxicities.
c. providers can adjust doses as needed.
d. the staff can ensure that the U.S. Food and Drug Administration (FDA) regulations are met.
A
Adherence to drug regimens is a serious problem in the treatment of TB. Directly observed therapy (DOT) combined with intermittent dosing helps ensure adherence and increases the chance of success. Patients report drug side effects to providers; it is not necessary to give drugs in the clinic to monitor this. Doses are adjusted based on response to treatment and not on DOT. The FDA regulations do not require DOT.
A patient comes to a clinic for tuberculosis medications 2 weeks after beginning treatment with a four-drug induction phase. The patient’s sputum culture remains positive, and no drug resistance is noted. At this point, the nurse will expect the provider to:
a. change the regimen to a two-drug continuation phase.
b. continue the four-drug regimen and recheck the sputum in 2 weeks.
c. obtain a chest radiograph and consider adding another drug to the regimen.
d. question the patient about adherence to the drug regimen.
B
In patients with positive pretreatment sputum test results, sputum should be evaluated every 2 to 4 weeks until cultures are negative and then monthly thereafter. In the absence of drug resistance, treatment with the same regimen should continue. Sputum cultures should become negative in over 90% of patients in 3 or more months. The induction phase should last 2 months, so this patient should remain on a four-drug regimen. It is not necessary to order a chest radiograph or to add another drug at this stage of treatment. The patient is stable and has not developed symptoms that cause concern, so the patient does not need to be questioned about adherence.
Which patient should begin treatment for tuberculosis?
a. A patient with HIV and a tuberculin skin test result of a 4-mm region of induration
b. A recent immigrant from a country with a high prevalence of TB with a 10-mm region of induration
c. A patient with no known risk factors who has a job-related tuberculin skin test result of a 12-mm area of induration
d. An intravenous drug abuser with a tuberculin skin test result of a 5-mm region of induration
B
The immigrant is considered to be at moderate risk, meaning that a 10-mm area of induration on a tuberculin skin test (TST) is considered a positive result. After being evaluated for active TB, this patient should be treated for latent TB. A patient with HIV is considered high risk, but this patient has a negative TST result of less than 5 mm. For a low-risk patient receiving a screening TST for a job, the area of induration must be 15 mm or greater to be considered a positive result. An IV drug abuser is in the moderate-risk category; an area of induration of 10 mm or greater is needed to be considered a positive TST result.
A healthcare worker who is asymptomatic has a screening TST result of 10 mm of induration during a pre-employment physical. What will the nurse reading this test tell the patient?
a. “This is a negative test, so you are cleared for employment.”
b. “You have latent TB and will need to take isoniazid for 6 to 9 months.”
c. “You need to have a chest radiograph and a sputum culture.”
d. “You will begin taking a four-drug regimen to treat tuberculosis.”
C
This patient has a moderate risk and a positive skin test result. Before beginning treatment for latent TB, active TB must be ruled out with chest X-rays and sputum cultures. This is not a negative test result in a moderate-risk individual. Latent TB needs to be confirmed with diagnostic testing. Treatment will not begin until tests have confirmed the diagnosis.
A patient is about to begin treatment for latent tuberculosis. The patient is an alcoholic, has difficulty complying with drug regimens, and has mild liver damage. What will the nurse tell this patient?
a. “You must stop drinking before adequate treatment can begin.”
b. “You must take isoniazid with close monitoring of hepatic function.”
c. “You must take rifampin daily for 4 months.”
d. “You will begin a regimen of isoniazid and rifampin.”
B
Isoniazid has an increased incidence of hepatotoxicity, especially when given with alcohol. Patients who consume alcohol or who have liver damage should receive isoniazid with caution and should have close monitoring of liver function. It is unrealistic to ask the alcoholic to stop drinking to undergo treatment. Rifampin is toxic to the liver, especially in alcoholics. Giving both drugs would only increase the risk of hepatotoxicity.
A patient has been taking isoniazid (Nydrazid) for 4 months for latent tuberculosis. The patient reports bilateral tingling and numbness of the hands and feet, as well as feeling clumsy. The nurse expects the provider to:
a. discontinue the isoniazid.
b. lower the isoniazid dose and add rifampin.
c. order pyridoxine 100 mg per day.
d. recheck the tuberculin skin test to see whether it worsens.
C
Patients sometimes develop peripheral neuropathy, characterized by paresthesias, clumsiness, and muscle aches. If these occur, they may be reversed by administering pyridoxine (vitamin B6). It is not necessary to discontinue the isoniazid. Lowering the isoniazid dose and adding rifampin is not indicated. Rechecking the TST is not indicated.
A patient is about to begin treatment with isoniazid. The nurse learns that the patient also takes phenytoin (Dilantin) for seizures. The nurse will contact the provider to discuss:
a. reducing the isoniazid dose.
b. reducing the phenytoin dose.
c. monitoring isoniazid levels.
d. monitoring phenytoin levels.
D
Isoniazid is a strong inhibitor of three cytochrome P450 enzymes, and inhibition of these enzymes can raise the levels of other drugs, including phenytoin. Patients taking phenytoin should have the levels of this drug monitored, and the dose should be reduced if appropriate. Reducing the dose of isoniazid is not indicated. It is not necessary to monitor isoniazid levels.
A patient with high-risk factors for tuberculosis will begin therapy for latent TB with isoniazid and rifampin. The nurse learns that this patient takes oral contraceptives. The nurse will counsel this patient to discuss _____ with her provider.
a. another birth control method
b. reducing the rifampin dose
c. reducing the isoniazid dose
d. increasing the oral contraceptive dose
A
Rifampin induces cytochrome P450 enzymes and can accelerate the metabolism of many drugs, including oral contraceptive pills (OCPs). Women taking OCPs should consider a nonhormonal form of birth control. Reducing the dose of rifampin or isoniazid is not indicated. Increasing the OCP dose is not recommended.
A patient is about to begin treatment for latent tuberculosis with a short course of daily rifampin. The patient asks why rifapentine (Priftin) cannot be used, because it can be given twice weekly. What will the nurse tell this patient about rifapentine?
a. It is more toxic than rifampin.
b. It is not approved for treatment of latent TB.
c. It is not well absorbed and thus not as effective.
d. It will stain contact lenses orange.
B
Rifapentine is indicated only for pulmonary TB. Rifapentine’s toxicity is similar to that of rifampin. Rifapentine is well absorbed. Both drugs stain contact lenses.
A patient who is being treated for HIV infection has a 5-mm area of induration after a routine TST. The patient’s chest radiograph is normal, and there are no other physical findings. The nurse will expect this patient to begin treatment with which drugs?
a. Isoniazid and rifabutin
b. Isoniazid and rifampin
c. Isoniazid and rifapentine
d. Isoniazid and pyrazinamide
A
Rifabutin is used off-label as an alternative to rifampin to treat TB in patients with HIV, because it has less impact on the metabolism of protease inhibitors. The effects of rifapentine on protease inhibitors is similar to those of rifampin. Pyrazinamide is not indicated.
