What is the standard initial therapy for active pulmonary TB?

• A. RIPE therapy for 2 months, followed by isoniazid and rifampin for 4 months
• B. Isoniazid monotherapy for 6 months
• C. Rifampin and ethambutol for 3 months
• D. Pyrazinamide monotherapy for 6 months

Answer: (A)

Active pulmonary TB is treated with an initial intensive phase using four first-line drugs for two months, followed by a four-month continuation phase with two drugs. This RIPE approach—rifampin, isoniazid, pyrazinamide, and ethambutol for two months—rapidly reduces the mycobacterial load and helps prevent resistance. After the initial phase, the regimen continues with isoniazid and rifampin for four more months, totaling six months of therapy, which is the standard for drug-susceptible TB. Monotherapy or regimens missing one or more of these drugs fail to eradicate the bacilli effectively and risk developing resistance, which is why they aren’t appropriate.