What is the initial phase of treatment for active TB disease?

• A. 4 drugs for 8 weeks to 3 months
• B. 2 drugs for 4 weeks
• C. 3 drugs for 6 months
• D. 4 drugs for 12 months

Answer: (D)

The initial phase is an intensive, four-drug regimen given for about two months to rapidly reduce the mycobacterial load and prevent the development of drug resistance. For drug-susceptible TB, this means using isoniazid, rifampin, pyrazinamide, and ethambutol together for roughly 8 weeks. After this, treatment continues with a two-drug regimen (typically isoniazid and rifampin) for about four more months, totaling around six months of therapy. Extending the intensive four-drug phase to 12 months isn’t standard for drug-susceptible TB and would expose patients to unnecessary drug exposure and toxicity; longer durations are reserved for specific, resistant TB cases or particular clinical situations.