This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'A new antifungal medication is being tested in Phase I clinical trials. Examination of the pharmacokinetic propeies of the drug reveals that the half-life of the drug is 6 hours. If a continuous intravenous infusion of this drug were staed on a research subject, how long would it take to reach 75% of steady state? \nSelect and explain. \nA. 3, B. 6, C. 9, D. 12', 'role': 'user'}, {'content': "Answer: D \nExplanation: The rule of thumb is that the plasma concentration will reach 50% in one half-life, 75% in two half-lives, 87.5% in three half-lives, etc., so that the difference between the current drug level and 100% halves with each half-life. In this instance, it takes two half-lives to reach 75%. The half-live of this drug is 6 hours, so two half-lives is 12 hours. 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 & Gilman's The Pharmacological Basis of Therapeutics, 12e.", 'role': 'assistant'}]