A 55-year-old African-American man, T.F., presents to your ER with headache, fever (102?F), muscle aches, and cough; his symptoms have rapidly worsened since onset (24 hours). T.F. received the inactivated influenza immunization 10 days earlier but is diagnosed with influenza A. T.F. had a renal transplant several years ago. His current medicines include tacrolimus (Prograf, Astellas Pharma), prednisone, mycophenolate mofetil (MMF) (CellCept, Roche), and furosemide 40 mg daily. T.F.'s SrCr51.8. The resident is considering antiviral therapy and asks your opinion. What do you suggest?