chapter 41: antitubercular drugs

A patient is receiving isoniazid (INH) for the treatment of tuberculosis. Which vitamin does the nurse anticipate administering with the INH to prevent isoniazid-precipitated peripheral neuropathies? A) Vitamin C B) Vitamin B12 C) Vitamin D D) Vitamin B6

D) Vitamin B6 Pyridoxine (vitamin B6) may be indicated to prevent isoniazid-precipitated peripheral neuropathies and numbness, tingling, or burning of the extremities.

what is isoniazid also called?

INH

isoniazid MOA

INHIBITS THE SYNTHESIS OF CELL WALL COMPONENTS, and is taken up by mycobacterial cells and undergoes hydrolysis to isonicotinic acid, which reacts with cofactor NAD to form a defective NAD that is no longer active as a coenzyme for certain life-sustaining reactions in the Mycobacterium tuberculosis organism

tubercle bacilli is a common synonym for?

MTB

do antitubercular drugs need to be taken at the same time each day?

YES, patients must follow the regimen

are patients to be started on a regimen with multiple antitubercular drugs before the results of the susceptibility tests are back?

YES, this helps to reduce chances of development of resistance

are mycobacterium aerobic or anaerobic?

aerobic bacillus

drugs used to treat infections caused by mycobacterium bacterial species

antitubercular

why should you watch for slow acetylators in patients taking isoniazid?

because the drug is metabolized in the liver through acetylation and could result in toxicity if person is a slow acetylator

The nurse is teaching a patient who is starting antitubercular therapy with rifampin. Which adverse effects would the nurse expect to see? a. Headache and neck pain b. Gynecomastia c. Reddish brown urine d. Numbness or tingling of extremities

c. Reddish brown urine

therapeutic effects of antitubercular drugs?

decrease in symptoms of TB, such as cough and fever

what happens when isoniazid interacts with antacids?

decreased isoniazid levels

problems with successful therapy occur because of?

patient nonadherence to drug therapy and the increased incidence of drug-resistant organisms

what should your patient do when they experience these adverse effects: fatigue, N/V, numbness and tingling of the extremities, fever, loss of appetite, depression, and jaundice

report it to the prescriber immediately

what is rifampin's trade name?

rifadin

antitubercular contraindications

severe drug allergy, major renal or liver dysfunction, chronic alcohol use

where is isoniazid metabolized?

the liver

antitubercular drugs are primarily used for?

the prophylaxis or treatment of TB

isoniazid contraindications

those with previous isoniazid-associated hepatic injury or any acute liver disease

how is isoniazid metabolized in the liver?

through a process called acetylation

why are drug susceptibility tests to be performed on the first mycobacterium species that is isolated from a patient specimen?

to prevent the development of multidrug-resistant TB (MDR-TB)

isoniazid indications

treatment and prevention of clinical TB

an infectious disease caused by species of mycobacterium

tuberculosis

can TB be cured?

with appropriate antibiotic treatment, most cases can be cured and usually involves taking several antibiotic drugs for at least 6 months and sometimes for as long as 12 months

reduction of infectiousness in a patient with TB usually takes how long?

within 2 weeks of the initiation of drug therapy

rifampin MOA

(inhibit protein synthesis) inhibit RNA synthesis and may also inhibit DNA synthesis

rifampin indications

-treatment of clinical TB -treats diseases caused by mycobacteria other than M. tuberculosis -preventive therapy in patients exposed to isoniazid-resistant M. tuberculosis -eliminate meningococci form the nasopharynx of asymptomatic Neisseria meningitidis carries when risk for meningococcal meningitis is high -chemoprophylaxis in contact of patients with HiB infection -leprosy -endocarditis caused by MRSA, chronic staph prostatitis, and multiple-antiinfective-resistant pneumococci

What instruction should the nurse include for a client prescribed rifampin (Rifadin) and isoniazid (Nydrazid) prophylactically secondary to TB exposure? A. Advise that these drugs will only need to be taken for 7 to 10 days. B. Remind that sunscreen is not needed during outdoor activities. C. Explain that isoniazid may decrease blood serum glucose in susceptible people. D. Emphasize that oral contraceptives become ineffective when given with rifampin.

D. Emphasize that oral contraceptives become ineffective when given with rifampin. Women taking oral contraceptives who are prescribed rifampin must be switched to another form of birth control because oral contraceptives become ineffective when given with rifampin. These medications must be taken long term because mycobacterium is slow growing. They can cause photosensitivity, necessitating the use of sunscreen. Finally, isoniazid may increase, not decrease, serum glucose levels.

When assessing for adverse effects to Rifamate (combination isoniazid and rifampin), the nurse would monitor which laboratory values? (Select all that apply.) A. Cholesterol B. Uric acid levels C. Sputum cultures D. Liver function tests E. Complete blood cell count

D. Liver function tests E. Complete blood cell count Rifamate can lead to impairment of liver function as well as hematologic disorders. Assessment of sputum cultures confirms the diagnosis but is not related to adverse effects. The drug does not affect uric acid levels or cholesterol.

The nurse anticipates a prescription for vitamin supplementation for a client who is receiving isoniazid (Nydrazid) therapy. What vitamin supplement is usually prescribed with isoniazid? A. Folate B. Calcium C. Vitamin E D. Vitamin B6

D. Vitamin B6 Pyridoxine (vitamin B6) is often given concurrently with isoniazid to prevent the adverse effect of isoniazid induced peripheral neuropathy associated with neurotoxicity.

The nurse is monitoring for liver toxicity in a patient who has been receiving long-term isoniazid therapy. Manifestations of liver toxicity include: (Select all that apply.) a. Orange discoloration of sweat and tears b. Darkened urine c. Dizziness d. fatigue e. Visual disturbances f. Jaundice

b. Darkened urine d. fatigue f. Jaundice

a vaccine injection derived from an inactivated strain of Mycobacterium bovis

bacilli calmette-guerin (BCG)

is isoniazid a bacteriostatic or bactericidal drug?

bactericidal because it disrupts cell wall synthesis

why is the use of multiple medications when combating an infection better?

because the use of multiple medications reduces the possibility of the organism's becoming drug resistant

what happens when rifampin interacts with beta blockers, benzos, cyclosporine, oral anticoagulants, oral antidiabetics, oral contraceptives, phenytoin, quinidine, sirolimus, and theophylline?

decreased therapeutic effects of these drugs (increased metabolism)

If the prescriber has ordered collection of a sputum specimen to test for acid-fast bacilli, it is best to obtain the sample when?

early in the morning (most common order is for 3 consecutive morning specimens and a repeat specimen several weeks later)

are the most drug susceptible organisms those with faster or slower metabolic activity?

faster

TB is most commonly characterized by what in the lungs?

granulomas

rifampin adverse effects

hepatitis, hematologic disorders, red-orange-brown discoloration of urine, tears, sweat, and sputum

MTB is transmitted from which 3 sources?

humans, cattle (bovine), and birds (avian)

what happens when isoniazid interacts with cycloserine, ethionmide, or rifampin?

increased CNS and hepatic toxicity

what happens when isoniazid interacts with phenytoin and carbamazepine?

increased phenytoin and carbamazepine effects (decreased metabolism)

the primary and most commonly prescribed tuberculostatic drug

isoniazid

what is the drug of choice for treating TB?

isoniazid

rifampin contraindications

known drug allergy to rifampin or any other rifamycin (rifabutin, rifapentine)

common infection sites for mycobacterium

lung (primary site), brain, bone, liver, kidney

how long can therapy for TB last?

may last up to 24 months

what are the signs and symptoms of peripheral neuropathy?

numbness, burning, and tingling of the extremities

a diagnostic injection given intradermally in doses of 5 tuberculin units (0.1 mL) to detect exposure to the tuberculosis (TB) organism

purified protein derivative (PPD)

isoniazid is noted for causing a deficiency in?

pyridoxine, and for this reason supplements of vitamin B6 is often given concurrently with isoniazid

how is TB passed on?

through droplets

antitubercular therapy effectiveness depends on?

type of infection, adequate dosing, sufficient duration of treatment, adherence to drug regimen, selection of an effective drug combination

rifampin may cause? (adverse effects)

urine, salive, tears, and sweat to be red-orange-brown colored

can oral pills be given with meals?

yes, this helps reduce GI upset, even though recommendations are to take them 1 hour before or 2 hours after meals

A patient with tuberculosis has been taking antitubercular drugs. A sputum culture is ordered to test for acid-fast bacilli. When is the best time for the nurse to obtain the sputum culture? A) In the morning B) Noon C) Five o'clock in the evening D) Ten o'clock in the evening

A) In the morning If the prescriber has ordered collection of a sputum specimen to test for acid-fast bacilli, it is best to obtain the sample early in the morning. The most common order is for three consecutive morning specimens, with a repeat specimen several weeks later.

A patient with a diagnosis of tuberculosis (TB) will be taking isoniazid (INH) as part of the anti-TB therapy. When reviewing the patient's chart, the nurse finds documentation that the patient is a "slow acetylator." This means that: A) the dosage of INH may need to be lower to prevent INH accumulation. B) the dosage of INH may need to be higher due to the slow acetylation process. C) he should not take INH. D) he will need to take a combination of anti-TB drugs for successful therapy.

A) the dosage of INH may need to be lower to prevent INH accumulation. When INH is taken by slow acetylators, the INH accumulates because there are not enough liver enzymes to break down the INH. Therefore, the dosages of INH may need to be adjusted downward to prevent toxicity.

The patient's wife is taking rifampin to prevent her from developing a tuberculosis infection. Which statement by the wife indicates that further teaching is needed? A) "Because my oral contraceptives will not work while I am taking rifampin, I will use another form of birth control." B) "I will take the medication for one week and then stop." C) "I will avoid prolonged exposure to the sun." D) "My urine may turn a reddish color when taking rifampin."

B) "I will take the medication for one week and then stop." Antitubercular therapy is taken for long periods of time, often 24 months. Although this patient does not have an active infection at this time and is taking the rifampin to prevent an infection, the nurse should further investigate the length of time the medication is ordered. All other statements are true.

A patient has an extremely severe infection with a Mycobacterium that is resistant to all but one antitubercular drug; however, the patient has had an allergic reaction to that drug in the past. What does the nurse anticipate as being ordered for this patient? A) A combination of antitubercular drugs will be chosen to fight the infection. B) The patient will receive the drug and supportive care to help him tolerate the antitubercular therapy. C) The patient will remain on isolation precautions until his cough clears. D) There is nothing that can be done with this patient.

B) The patient will receive the drug and supportive care to help him tolerate the antitubercular therapy. It must be recognized that the urgency of treating a potentially fatal infection may have to be balanced against any prevailing contraindications. In extreme cases, patients are sometimes given a drug to which they have some degree of allergy with supportive care that enables them at least to tolerate the medication. Examples of such supportive care are treatment with antipyretics (e.g., acetaminophen), antihistamines (e.g., diphenhydramine), or even corticosteroids (e.g., prednisone, methylprednisolone).

A home care nurse is visiting a patient with a diagnosis of TB. The patient traveled abroad two months ago. He lives with his wife and 5-year-old son. The patient tells the nurse that he is concerned his son will also get TB so he wants to share his pills with his son. What is the best response by the nurse? A) "That is a good idea. Children should not be exposed to TB." B) "You should give your son half of the dose you take." C) "Do not share any of your medications with anyone. Contact your son's health care provider to discuss your concerns." D) "Children have an immune system that makes them immune to TB."

C) "Do not share any of your medications with anyone. Contact your son's health care provider to discuss your concerns." Medications of any kind should never be shared with any other person. In particular, antitubercular drugs are age specific. Assessment of age is also important, because the likelihood of adverse reactions and toxicity is increased in elderly patients due to age-related liver and kidney dysfunction. Additionally, the safety of these drugs in children 13 years of age and younger has not been established.

Four weeks after beginning antitubercular drug therapy on an outpatient basis, the patient reports that he still experiences night sweats. What does the nurse identify as the main concern at this time? A) He is not taking his medication properly. B) More time is needed to see a therapeutic response. C) His infection may be resistant to the drug therapy ordered. D) He may have contracted a different strain of tuberculosis (TB).

C) His infection may be resistant to the drug therapy ordered. The nurse should not jump to conclusions that the patient is not taking his medication properly. An improvement should start to occur within 2 weeks of starting drug therapy, but this may not occur if the patient's TB is not sensitive to the prescribed drugs. An evaluation of the drug therapy will be needed

The patient tells the nurse, "I had a shot after I returned from my trip overseas. I thought that was supposed to stop me from getting a tuberculosis infection." What information regarding tuberculosis- related injections does the nurse identify as being true? A) BCG is used to prevent infection with tuberculosis for women of childbearing age. B) A positive result for a PPD test is indicated by redness at the site of injection. C) PPD is a diagnostic injection given intradermally to detect exposure to the TB organism. D) BCG is a vaccine injection derived from an activated strain of Mycobacterium bovis.

C) PPD is a diagnostic injection given intradermally to detect exposure to the TB organism. PPD is a diagnostic injection given intradermally in doses of 5 tuberculin units (0.1 mL) to detect exposure to the TB organism. A positive result is indicated by induration (not erythema) at the site of injection and is known as the Mantoux reaction, named for the physician who described it. BCG is used in much of the world to vaccinate young children against tuberculosis. Although it does not prevent infection, evidence indicates that it reduces active tuberculosis by 60% to 80% and is even more effective at preventing more severe cases involving dissemination of infection throughout the body.

Which client statement indicates to the nurse that the client understands the discharge teaching for ethambutol (Myambutol)? A. "Constipation will be a problem, so I will increase the fiber in my diet." B. "Dizziness and drowsiness are common adverse effects with this drug." C. "I will need to have my vision checked periodically while I am taking this drug." D. "This medication may cause my bodily secretions to turn red-orange-brown."

C. "I will need to have my vision checked periodically while I am taking this drug." Ethambutol can cause optic neuritis. Ophthalmologic examinations should be performed periodically to assess visual acuity

What information should the nurse provide to a client prescribed rifampin (Rifadin)? A. Oral contraception is the preferred method of birth control when using rifampin. B. The patient will only need to take this medication for the prescribed 14-day period. C. A nonharmful adverse effect of this medication is red-orange discoloration of urine, sweat, tears, skin, salvia, and feces. D. Peripheral neuropathy is an expected side effect, and the patient should report any numbness or tingling of the extremities.

C. A nonharmful adverse effect of this medication is red-orange discoloration of urine, sweat, tears, skin, salvia, and feces. Red-orange-brown discoloration of the skin, sweat, tears, urine, feces, sputum, saliva, and tongue as an adverse effect of the drug, but it is not harmful. Rifampin does not cause peripheral neuropathies (isoniazid does), but it does interfere with the effectiveness of oral contraceptives. All antitubercular drugs need to be taken long term to eradicate the slow-growing mycobacterium lying deep within the tissues.

Before discharge, the nurse is reviewing a client's prescribed medication regimen for tuberculosis (TB). The client asks the nurse why pyridoxine (vitamin B6) has been prescribed while continuing to take isoniazid (Nydrazid) to treat TB. What is the nurse's best response? A. "Multidrug therapy is necessary to prevent the occurrence of resistant bacteria." B. "You really should not be on that drug. I will check with the health care provider." C. "Pyridoxine is another antitubercular drug that will work synergistically with the isoniazid." D. "Pyridoxine will help prevent numbness, and tingling that can occur secondary to the isoniazid."

D. "Pyridoxine will help prevent numbness, and tingling that can occur secondary to the isoniazid." Isoniazid can cause neurotoxicity. Pyridoxine, vitamin B6, is the drug of choice to prevent this adverse reaction. It is not an antiinfective drug and thus will not work to destroy the mycobacterium or prevent drug resistance.

Bedaquiline (Sirturo) is prescribed for a patient, and the nurse is providing instructions to the patient about the medication. Which statement by the patient indicates a correct understanding of the instructions? a. "I will take this with food." b. "I need to take this 1 hour before breakfast." c. "I can stop this drug if the side effects bother me." d. "It's okay to have a glass of wine while taking this drug."

a. "I will take this with food."

The nurse is counseling a woman who is beginning antitubercular therapy with rifampin. The patient also takes an oral contraceptive. Which statement by the nurse is most accurate regarding potential drug interactions? a. "You will need to switch to another form of birth control while you are taking the rifampin." b. "Your birth control pills will remain effective while you are taking the rifampin." c. "You will need to take a stronger dose of birth control pills while you are on the rifampin." d. "You will need to abstain from sexual intercourse while on the rifampin to avoid

a. "You will need to switch to another form of birth control while you are taking the rifampin."

During antitubercular therapy with isoniazid, a patient received another prescription for pyridoxine. Which statement by the nurse best explains the rationale for this second medication? 669 a. "This vitamin will help to improve your energy levels." b. "This vitamin helps to prevent neurologic adverse effects." c. "This vitamin works to protect your heart from toxic effects." d. "This vitamin helps to reduce gastrointestinal adverse effects."

b. "This vitamin helps to prevent neurologic adverse effects."

While monitoring a patient, the nurse knows that a therapeutic response to antitubercular drugs would be: a. The patient states that he or she is feeling much better. b. The patient's laboratory test results show a lower white blood cell count. c. The patient reports a decrease in cough and night sweats. d. There is a decrease in symptoms, along with improved chest x-ray and sputum culture

d. There is a decrease in symptoms, along with improved chest x-ray and sputum culture

When counseling a patient who has been newly diagnosed with TB, the nurse will make sure that the patient realizes that he or she is contagious a. during all phases of the illness. b. any time up to 18 months after therapy begins. c. during the postictal phase of TB. d. during the initial period of the illness and its diagnosis.

d. during the initial period of the illness and its diagnosis.

isoniazid adverse effects

peripheral neuropathy, hepatotoxicity, optic neuritis and visual disturbances, hyperglycemia

lack of clinical response to therapy indicates what?

possible drug resistance

isoniazid and rifampin belong to which drug class? are they primary or secondary?

primary antitubercular drugs

what can combat neurologic adverse effects associated with INH therapy?

pyridoxine

can isoniazid cause false-positive readings on urine glucose tests?

yes

can isoniazid increase serum levels of the liver function enzymes alanine aminotransferase and aspartate aminotransferase?

yes

does rifampin cause oral contraceptives to become ineffective?

yes, another form of birth control will be needed