<prompt> While receiving mechanical ventilation, a 57-year-old man contracts pneumonia caused by Pseudomonas aeruginosa. The patient is given antibiotic therapy with ceftazidime and gentamicin. Assuming the half-life of gentamicin is 3 hours in this paicular patient, what percentage of the initial dose will most likely remain in his body 6 hours later?12.5253350  <response>: The half-life of a medication is the time required for one-half the total amount of the medication to be excreted from the body. For any given first-order elimination process, 50 of the initial amount of drug is eliminated at the end of the first half-life, 50 of the remaining amount of drug in the body is eliminated at the end of the second half-life, and so on. Therefore, after 3 hours 50 of the gentamicin will be remaining in the body. After another 3 hours 6 hours total, 50 of the remaining 50 will be eliminated. In other words, after 6 hours, 75 of the gentamicin will be eliminated, and 25 of the initial dose will remain. Ref: Buxton I.L., Benet L.Z. 2011. Chapter 2. Pharmacokinetics: The Dynamics of Drug Absorption, Distribution, Metabolism, and Elimination. In L.L. Brunton, B.A. Chabner, B.C. Knollmann Eds, Goodman Gilmans The Pharmacological Basis of Therapeutics, 12e. 