A middle-aged man with chronic renal failure is diagnosed to have sputum-positive pulmonary tuberculosis. His creatinine clearance is 25 ml/min. All of the following drugs need modification in doses EXCEPT :
Rifampicin is secreted in bite, so it does not require dose adjustment in renal failure.
Isoniazid
Streptomycin
Rifampicin
Ethambutol