<prompt> More than 90 of this drug is excreted in the urine in intact form. Because its urinary solubility is low, patients should be well hydrated to prevent nephrotoxicity. The drug is:IndinavirZidovudineAcyclovirAmantadine  <response>: - Both indinavir and acyclovir can cause nephrotoxicity and renal stone formation. - But indinavir is metabolized mainly in the liver and acyclovir is excreted unchanged in the urine. - Therefore patients should be well hydrated to prevent nephrotoxicity of acyclovir. 