Why TB patient is recommend a regimen of 4 drugs on 1st visit -
During first visit (intensive phase) 3 or more drugs are combined to kill off as many bacilli as possible . The more rapidly the bacilli are killed initially, the less likely are "persisters" to emerge. The risk of relapse is also lessened. Ref: PARK&;S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 23rd edition , Page :187
To avoid emergence of persistors
To avoid side effects
To cure early
None
Communicable diseases