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': 'Young child weighing 20 kg was given a drug in the dose 100mg/kg body weight. The plasma concentration of the drug is 2mg/ dl and the clearance is 200 ml/hr. What is the time required to reach steady state plasma concentration - \nSelect and explain. \nA. 10 hrs, B. 20hrs, C. 30hrs, D. 40hrs', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 20 hours Volume of distribution = total dose/plasma concentration Total dose= dose/ kg x body weight = 100 x 20 = 2000 mg Volume of distribution = 2000/2 = 1000 Half life = 0.693 x Volume of distribution/ clearance = 0.693 x 1000/200 = 3.5 hours Time required to reach steady state plasma concentration is 5.5 half lives = 5.5 x 3.5 = 19.25 hours Therefore the most appropriate answer is 20 hours.", 'role': 'assistant'}]