RNTCP and Treatment of TB, MDR TB, XDR TB, and MAC Infection

The Revised National Tuberculosis Control Program (RNTCP) is a government initiative in India aimed at controlling tuberculosis through the Directly Observed Treatment, Short-course (DOTS) strategy. This program ensures that patients adhere to the full treatment regimen, helping to prevent drug resistance.

• DOTS Strategy: Patients are observed during drug intake to ensure adherence.
• Patient Categories:
  • Category I: New smear-positive cases.
  • Category II: Previously treated cases like relapses and failures.
  • Category III: Less severe, smear-negative TB cases.
  • Category IV: MDR TB cases needing complex treatment.

• Isoniazid (INH): 5 mg/kg body weight
• Rifampicin (RIF): 10 mg/kg body weight
• Pyrazinamide (PZA): 25 mg/kg body weight
• Ethambutol (EMB): 15 mg/kg body weight

Treatment Duration

• Initial Phase: 2 months (HRZE: Isoniazid, Rifampicin, Pyrazinamide, Ethambutol)
• Continuation Phase: 4-6 months (HR: Isoniazid, Rifampicin)

MDR TB occurs when tuberculosis bacteria are resistant to at least isoniazid (INH) and rifampicin (RIF), two primary anti-TB drugs. This form of TB requires second-line drugs and prolonged treatment.

• Duration: 18-24 months.
• Drugs Used: Includes fluoroquinolones (e.g., levofloxacin), aminoglycosides (e.g., amikacin), ethionamide, cycloserine, and pyrazinamide.
• DOTS-Plus Strategy: Ensures drug adherence and regular monitoring specific to MDR TB patients.

XDR TB is a severe form of MDR TB with additional resistance to fluoroquinolones and at least one second-line injectable drug (e.g., amikacin). It poses greater treatment challenges.

• Duration: Often exceeds 24 months, with intensive monitoring.
• Drugs Used: Includes bedaquiline, linezolid, clofazimine, and others based on susceptibility testing.
• Challenges: Treatment is lengthy, toxic, and has a lower success rate compared to MDR TB.

MAC infection, caused by Mycobacterium avium complex (e.g., M. avium, M. intracellulare), primarily affects immunocompromised individuals, especially those with AIDS, and leads to lung infections, lymphadenitis, and disseminated disease.

• Drugs Used: Combination of clarithromycin or azithromycin, ethambutol, and rifabutin.
• Duration: At least 12 months after culture conversion to prevent relapse.
• Considerations: Long-term therapy is needed due to slow bacterial growth and risk of recurrence.