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: Medicine
[{'content': 'A patient has serum creatinine of 150-300 micromol/L. Which of the following require dosage reduction: March 2011 \nSelect and explain. \nA. Ampicillin, B. Isoniazid, C. Gentamycin, D. Penicillin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C: Gentamycin Drugs whose dosage are affected in mild renal insufficiency (GFR 20-50 mL/ min or serum creatinine 150-300 micromol/L) are: ACE inhibitors, Aminoglycosides, chlorpropamide, digoxin, fibrates, lithium and zidovudine', 'role': 'assistant'}]