The antidepressant fluoxetine has a half life of about 3 days, what percentage of a dose remains in the body after one day

Answer 1

1/2 = e^rt = e^3r

ln.5 = 3r

r = ln.5/3 = -.231= daily decay rate of about 23.1%

in one day

A =Pe^rt = 2e^-.231t = 2/e^.231(1) = about 1.57 in one day

1.57/2 = about .785 = 78.5% of a dose left in the body after one day

A= Pe^-.231(3) = 2/e^.693 = 1 in 3 days. 1 is half 2. 1/2 =50% left after 3 days