<prompt> Why TB patient is recommend a regimen of 4 drugs on 1st visit -To avoid emergence of persistorsTo avoid side effectsTo cure earlyNone  <response>: 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 