This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
More than 90% of this drug is excreted in the urine in intact form. Because it's urinary solubility is low, patient should be well hydrated to prevent nephrotoxicity. The drug is: 
Select and explain. 
A. Indinavir, B. Zidovudine, C. Acyclovir, D. Amantadine
C: Acyclovir
Answer: C: Acyclovir 
Explanation: (Ref: Katzung 10/e p793; KDT 6/e 769) Both indinavir and acyclovir can cause nephrotoxicity bad renal stone formation. But indinavir is metabolized mainly in the liver and acyclovir is excreted unchanged in the urine.