Which statement best explains how the standard TB treatment is divided into two phases?

Which statement best explains how the standard TB treatment is divided into two phases?

• A. The continuation phase begins after the initial phase and includes rifampin and isoniazid
• B. The initial phase uses fewer drugs than the continuation phase
• C. The two phases are identical in drug regimen
• D. The continuation phase uses pyrazinamide and ethambutol

Answer: (A)

The two-phase TB treatment is designed to quickly reduce the bacterial load and then finish eradicating any remaining bacilli with the core drugs. In the initial, intensive phase, a four-drug regimen (rifampin, isoniazid, pyrazinamide, and ethambutol) is used to rapidly drop the bacillary population and help prevent resistance. After this phase, the continuation phase starts and uses only rifampin and isoniazid for the remaining months to complete eradication. This structure is why the statement describing the continuation phase as beginning after the initial phase and including rifampin and isoniazid best fits the standard regimen, whereas other statements conflict with which drugs are used in each phase.

The two-phase TB treatment is designed to quickly reduce the bacterial load and then finish eradicating any remaining bacilli with the core drugs. In the initial, intensive phase, a four-drug regimen (rifampin, isoniazid, pyrazinamide, and ethambutol) is used to rapidly drop the bacillary population and help prevent resistance. After this phase, the continuation phase starts and uses only rifampin and isoniazid for the remaining months to complete eradication. This structure is why the statement describing the continuation phase as beginning after the initial phase and including rifampin and isoniazid best fits the standard regimen, whereas other statements conflict with which drugs are used in each phase.