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
Which of the following drugs is avoided in a patient with high serum creatinine (> 3 mg/dl) ? 
Select and explain. 
A. Gentamicin, B. Azithromycin, C. Moxifloxacin, D. Amlodipine
A: Gentamicin
Answer: A: Gentamicin 
Explanation: None