<prompt> Elimination after 4 half-lives in first-order kinetics is:8493.7580.7575  <response>: The Plasma half-life t12 of a drug is the time taken for its plasma concentration to be reduced to half of its original value 1 t 12-50 drug is eliminated. 2 t 12 -75 50 25 drug is eliminated. 3 t 12 -87.5 50 25 12.5 drug is eliminated 4 t 12 -93.75 50 25 12.5 6.25 drug is eliminated In first-order kinetics-t 12 remains constant because Volume of distribution and Clearance do not change with dose. after 5-6 t12 drug is almost completely eliminated from the body Ref: KD Tripathi pharmacology 7th edition page.no: 31 