How long do i wait after i take the plan b pill for it to be effective and what do i do?

Do not wait. : Take as soon as possible. The efficacy of the emergency contraception decline significantly after 72 hrs of exposing to a pregnancy risk. Buy in any pharmacy , no prescription is necessary and use as indicated.

Plan B: Use Plan B as soon as possible after episode of failed birth control.Plan B One-Step is up to 89 % effective when taken within 72 hours (3 days) after unprotected sex. It can reduce chance of pregnancy by up to 95% if used within 24 hours. It continues to reduce the risk of pregnancy up to 120 hours (5 days) after unprotected sex, but is less effective as time passes.