1. Respiratory System Drugs
Antitubercular Drugs

2. Antitubercular Drugs Tuberculosis (TB)
Caused by Mycobacterium tuberculosis
Antitubercular drugs treat all forms of Mycobacterium

3. Antitubercular Drugs Mycobacterium Infections
Common infection sites
Lung (primary site)
Brain
Bone
Liver
Kidney
Aerobic bacillus
Passed from infected:
Humans
Cows (bovine) and birds (avian)
Much less common

4. Antitubercular Drugs Mycobacterium Infections
Tubercle bacilli are conveyed by droplets
Droplets are expelled by coughing or sneezing, then gain entry into the body by inhalation
Tubercle bacilli then spread to other body organs via blood and lymphatic systems
Tubercle bacilli may become dormant, or walled off by calcified or fibrous tissue

5. Antitubercular Drugs Tuberculosis - Pathophysiology
M. tuberculosis – gram-positive, acid-fast bacillus
Spread from person to person via airborne droplets
Coughing, sneezing, speaking – disperse organism and can be inhaled
Not highly infectious – requires close, frequent, and prolonged exposure
Cannot be spread by hands, books, glasses, dishes, or other fomites

6. Antitubercular Drugs Tuberculosis – Clinical Manifestations
Early stages – free of symptoms
Many cases are found incidentally
Systemic manifestations:
Fatigue, malaise, anorexia, weight loss, low-grade fevers, night sweats
Weight loss – occurs late
Characteristic cough – frequent & produces mucoid or mucopurulent sputum
Dull or tight chest pain
Some cases: acute high fever, chills, general flulike symptoms, pleuritic pain, productive cough
HIV Pt with TB: Fever, cough, weight loss –
Pneumocystic carinii pneumonia (PCP)

7. Antitubercular Drugs Tuberculosis – Diagnostic Studies
Tuberculin Skin Testing -- + reaction 2-12 weeks after the initial infection
PPD – Purified protein derivative – used to detect delayed hypersensitivity response
Two-step testing – health care workers
5mm > induration – Immunosuppressed patients
10 mm> “at risk” populations & health are workers
15 mm> Low risk people
Chest X-ray -- used in conjunction with skin testing
Multinodular lymph node involvement with cavitation in the upper lobes of the lungs
Calcification – within several years after infection
Bacteriologic Studies –
Sputum, gastric washings –early morning specimens for acid-fast bacillus -- three consecutive cultures on different days
CSF or pus from an abscess

8. Antitubercular Drugs Tuberculosis – Medical Management
May be treated as outpatient
Depends on debility and severity of symptoms
Mainstay of treatment: drug therapy for active disease:
Five primary drugs:
Isoniazid (INH) * (primary drug used)
Rifampin
Pyrazinamide
Streptomycin
Ethambutol
Combination 4 drug therapy
HIV patients cannot take rifampin – interferes with antiretroviral drug effectiveness

10. Antitubercular Drugs Second-Line Drugs capreomycin amikacin
cycloserine levofloxacin
ethionamide ofloxacin
kanamycin
para-aminosalicyclic acid (PAS)

11. Antitubercular Drug Therapy Considerations
Perform drug-susceptibility testing on the first Mycobacterium sp. that is isolated from a patient specimen to prevent the development of MDR-TB(Multidrug-resistant TB)
Even before the results of susceptibility tests are known, begin a regimen with multiple antitubercular drugs
Adjust drug regimen once the results of susceptibility testing are known
Monitor patient compliance closely during therapy
Problems with successful therapy
patient nonadherence to drug therapy
increased incidence of drug-resistant

12. Antitubercular Therapy
Effectiveness depends upon:
Type of infection
Adequate dosing
Sufficient duration of treatment
Drug compliance
Selection of an effective drug combination

13. Antitubercular Therapy
Problems
Drug-resistant organisms
Drug toxicity
Patient noncompliance
Multidrug-resistant TB (MDR-TB)

14. Antitubercular Drugs Isoniazid (INH)
Drug of choice for TB
Resistant strains of Mycobacterium emerging
Metabolized in the liver through acetylation—watch for “slow acetylators”
Used alone or in combination with other drugs
Used for the prophylaxis or treatment of TB

15. Antitubercular Drugs Adverse Effects
INH
Peripheral neuritis, hepatotoxicity
Ethambutol
Retrobulbar neuritis, blindness
Rifampin
Hepatitis, discoloration of urine, stools

16. Antitubercular Drugs Nursing Implications
Thorough medical history and physical assessment
Perform liver function studies in patients who are to receive isoniazid or rifampin (especially in elderly patients or those who use alcohol daily)
Assess for contraindications to the various drugs, conditions for cautious use, and potential drug interactions

17. Antitubercular Drugs Nursing Implications
Monitor for therapeutic effects
Decrease in symptoms of TB, such as cough and fever
C&S and CXR should confirm clinical findings
Observe for lack of clinical response to therapy, indicating possible drug resistance
Monitor for adverse effects
Instruct patients on the adverse effects that should be reported to the physician immediately
fatigue, nausea, vomiting, numbness and tingling of the extremities, fever, loss of appetite, depression, jaundice

18. Antitubercular Drugs Patient Education
Patient education is critical
Therapy may last for up to 24 months
Take medications exactly as ordered, the same time every day
Emphasize the importance of strict adherence to regimen for improvement of condition or cure
Remind patients that they are contagious during the initial period of their illness—instruct in proper hygiene and prevention of the spread of infected droplets
Emphasize to patients to take care of themselves, including adequate nutrition and rest

19. Antitubercular Drugs Patient Education
Patients should not consume alcohol or take other medications, including OTC -- check with their physician
INH and rifampin cause oral contraceptives to become ineffective; another form of birth control will be needed
Patients who are taking rifampin should be told that their urine, stool, saliva, sputum, sweat, or tears may become reddish orange; even contact lenses may be stained
Pyridoxine (Vitamin B6) may be needed to combat neurologic adverse effects associated with INH therapy
Oral preparations may be given with meals to reduce GI upset, even though recommendations are to take them 1 hour before or 2 hours after meals