<prompt> A middle-aged man with chronic renal failure is diagnosed to have sputum-positive pulmonary tuberculosis. His creatinine clearance is 25 mlmin. All of the following drugs need modification in doses EXCEPT :IsoniazidStreptomycinRifampicinEthambutol  <response>: Rifampicin is secreted in bite, so it does not require dose adjustment in renal failure. 