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 patient with normal renal function has received a daily maintenance dose of digoxin for 2 weeks, if the dosage is changed, the new steady state plasma digoxin concentration would be achieved in approximately \nSelect and explain. \nA. 2days, B. 1 week, C. 2 weeks, D. 4 weeks', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The time required to establish a new steady-state plasma drug concentration when maintenance doses are changed is approximately four half-lives, the same amount of time required to establish the initial steadystate level. Because the half-life of digoxin is approximately 1.6 days, the time required to reach a new steady state is approximately 7 days. Digitoxin has a much longer half-life of approximately 7 days and the time required to reach steady state with digitoxin is approximately 4 weeks. The time required to reach steady state is independent of dose or dosage interval', 'role': 'assistant'}]