When a patient takes 400 mg of an oral drug that has a half-life of 2 hours at noon,at which time will the patient's blood drug level first be less than 40 mg?

Question

Quizplus · Accepted Answer

With a half-life of 2 hours,the amount of drug remaining in the blood decreases by 50% every 2 hours.So,when 400 mg are given at noon,by 2:00 p.m. ,200 mg remain;by 4:00 p.m. ,100 mg remain;by 6:00 p.m. ,50 mg remain;by 8:00 p.m. ,25 mg remain;by 10:00 p.m. ,12.5 mg remain,and by midnight,6.25 mg remain.

When a Patient Takes 400 Mg of an Oral Drug