1. Introduction to Clinical Pharmacology Chapter 10 Antitubercular Drugs

2. Antitubercular Drugs: Actions and Uses
Bacteriostatic against the M. tuberculosis bacillus: act to inhibit bacterial cell wall synthesis, which slows the multiplication rate of the bacteria
Ethambutol, isoniazid, pyrazinamide, and rifampin are considered primary drugs-used in initial phase
Secondary drugs are used to treat extrapulmonary and drug-resistant TB. Secondary drugs are less effective and more toxic than primary drugs used to treat TB.
Prophylactic therapy-to prevent spreading disease
Used with other drugs to treat active TB—exception isoniazid (INH)

3. Antitubercular Drugs: Treatment
Standard treatment:
Initial phase- lasts approximately 2 months, drugs are used to kill the rapidly multiplying M. tuberculosis and to prevent drug resistance.
Elements that will determine continuation phase are noninclusion of pyrazinamide in the initial treatment phase, positive sputum culture after completion of initial treatment
Continuing phase- lasts approximately 4 to 7 months and the entire prophylactic treatment spans 6 to 9 months. Will use isoniazid and rifampin
Retreatment:
Includes the use of four or more antitubercular drugs
Treatment is individualized based on the susceptibility of the microorganism
Will include ethionamide, aminosalicylic acid, cycloserine, and capreomycin

4. Ethambutol: Adverse Reactions
Generalized reactions:
Dermatitis and pruritus; joint pain; anorexia; nausea and/or vomiting
More severe reactions:
Anaphylactoid reactions; optic neuritis

5. Ethambutol: Contraindications and Precautions
Contraindicated in patients:
With a history of hypersensitivity to the drug; younger than 13 years
Used cautiously in patients:
During pregnancy (pregnancy category B); with hepatic or renal impairment; with diabetic retinopathy or cataracts

6. Isoniazid: Adverse Reactions
Generalized reactions:
Nausea and/or vomiting; epigastric distress; fever; skin eruptions; hematologic changes; jaundice; hypersensitivity
Toxicity:
Peripheral neuropathy
Severe, and sometimes fatal hepatitis

7. Isoniazid: Contraindications and Precautions
Contraindicated in patients:
With a history of hypersensitivity to the drug
Used cautiously in patients:
During pregnancy (pregnancy category C) or lactation and in patients with hepatic and renal impairment
Explain that foods that contain tyramine, such as aged cheese and meats, bananas, yeast products and alcohol should be avoided

8. Isoniazid: Interactions
Interactant drug
Effect of interaction
Aluminum salts
Reduced absorption of isoniazid
Anticoagulants
Increased risk for bleeding
Phenytoin (Dilantin)
Increased serum levels of phenytoin
Alcohol (in beverages)
Higher incidence of drug-related hepatitis

9. Pyrazinamide: Adverse Reactions
Generalized reactions:
Nausea and/or vomiting; diarrhea; myalgia; rashes
Hepatotoxicity:
Symptoms may range from none (except for slightly abnormal hepatic function test results) to a more severe reaction such as jaundice

10. Pyrazinamide: Contraindications, Precautions, and Interactions
Contraindicated in patients with known hypersensitivity to the drug; acute gout; severe hepatic damage
Use cautiously in patients during pregnancy and lactation; with hepatic and renal impairment; with HIV; with diabetes mellitus
Interaction: with allopurinol, colchicine, and/or probenecid—its effectiveness decreases

11. Rifampin: Adverse Reactions
Generalized reactions:
Nausea, vomiting
Epigastric distress, heartburn, fatigue
Vertigo, rash
Reddish-orange discoloration of body fluids
Hematologic changes, renal insufficiency

12. Rifampin: Contraindications, Precautions, and Interactions
Contraindicated in patients with known hypersensitivity to the drug
Used cautiously in patients with renal or hearing impairment; during pregnancy and lactation
Interactions: with antiretrovirals, digoxin; oral contraceptives; isoniazid; oral anticoagulants; oral hypoglycemics; chloramphenicol; phenytoin; verapamil
Type 2 diabetics need to be aware diabetic medication might need adjustment because of possible increased blood glucose readings

13. Nursing Process: Assessment
Preadministration assessment:
Assess a family history and a history of contacts, if the patient has active TB
C & S testing, CBC, X-ray studies, medication history, and allergy history
Ongoing assessment:
Observe the patient daily for the appearance of adverse reactions and report if found
Carefully monitor vital signs daily

14. Nursing Process: Nursing Diagnoses
Acute Pain
Risk for Injury-related to extremity numbness due to neurotoxicity
Imbalanced Nutrition: Less Than Body Requirements-due to gastric upset
Risk for Ineffective Self-Health Management-related to indifference, lack of knowledge, and long term treatment

15. Nursing Process: Planning
The expected outcome includes an optimal response to therapy:
Management of adverse drug reactions
Understanding of and compliance with the prescribed treatment regimen

16. Nursing Process: Implementation #1
Promoting an optimal response to therapy:
Allow time for the patient and family members to ask questions
Refer the patient to other health care workers, such as a social service worker or a dietitian

17. Nursing Process: Implementation #2
Monitoring and managing patients’ needs:
Acute Pain: frequent parenteral injections
Be careful to rotate the injection sites
Inspect previous injection sites for signs of swelling, redness, and tenderness
Notify if necessary

18. Nursing Process: Implementation #3
Monitoring and managing patients’ needs (cont.)
Imbalanced Nutrition: Less Than Body Requirements
Be aware of dosing regimen with/without food for ethambutol, pyrazinamide; monitor for gastric upset; use alternative dosing regimen or combination drugs; explain coloration of bodily fluids

19. Nursing Process: Implementation #4
Monitoring and managing patients’ needs (cont.)
Ineffective Therapeutic Regimen Management:
To help prevent the problem of noncompliance— directly observed therapy (DOT)
Tuberculosis caused by drug-resistant organisms should be considered in clients who have no response to therapy and in clients who have been treated in the past.

20. Nursing Process: Implementation #5
Educating the patient and family: careful patient and family education and close medical supervision are necessary
Explain that short-term therapy is of no value in treating this disease
Remain alert for statements made by the patient or family that may indicate future noncompliance with the drug regimen

21. Nursing Process: Evaluation
The therapeutic effect is achieved
Adverse reactions are identified, reported, and managed successfully
Pain or discomfort following IM or IV administration is relieved or eliminated
Patient and family demonstrate understanding of the drug regimen
Patient complies with the prescribed drug regimen

22. Nursing Process: Evaluation
Teaching points that can be used by the nurse to increase the likelihood for effective therapeutic outcomes include reinforcing that short-term treatment is ineffective; reviewing the drug therapy regimen, including the prescribed drug, doses, and frequency of administration; arranging for direct observation therapy with the client and family; and instructing the client about possible adverse reactions and the need to notify the prescriber should any occur.

23. Question #1 Is the following statement true or false?
The nursing diagnosis of Ineffective Self-Health Management may be especially important with patients considering the short-term therapy required to treat TB.

24. Answer to Question #1 False
The nursing diagnosis of Ineffective Self-Health Management may be especially important with patients considering the long-term therapy required to treat TB.

25. Question #2 Is the following statement true or false?
Directly observed therapy (DOT) involves a patient being directly watched by a health care provider when taking the antitubercular drugs.

26. Answer to Question #2 True
Directly observed therapy (DOT) involves a patient being directly watched by a health care provider when taking the antitubercular drugs.

27. Question #3
How long does a patient have to be on preventive therapy for exposure to tuberculosis?
A. 1 month
B. 2 months
C. 4 months
D. 6 months to 1 year

28. Answer to Question #3 D
Preventive therapy (prophylaxis for those exposed but who do not have active disease) involves one drug taken for 6 months to 1 year.