Clinical Twisters: Transplant patient develops flu

January 23, 2006

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?

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 SrCr=1.8. The resident is considering antiviral therapy and asks your opinion. What do you suggest?

Importantly, T.F.'s immunosuppressive regimen and timing of flu vaccine preclude effective protective response. Influenza treatment is appropriate if the clinical, regional, or lab findings support diagnosis and would send the clinical phamacist scrambling for oseltamivir. The ominous diagnosis of cytomegalovirus infection must also be considered, and antigenemia should be assessed.

Immunosuppression, drug-drug interactions, and severity of illness make this case complex. A successful outcome can be achieved, but the inpatient setting and comprehensive monitoring are essential.
Jeff Almgren, R.Ph.Clinical Pharmacy SpecialistBMT/PBSC ProgramJack Lionberger, M.D., Ph.D.Fellow in Oncology VA-Puget Sound Health Care System

Vaccination is the best way to prevent flu and complications. However, antibodies take two weeks to develop. Amantadine, rimantadine, zanamivir (Relenza, GlaxoSmithKline), and oseltamivir (Tamiflu, Roche) are approved for treating flu. Administered within two days of onset, they reduce illness duration by approximately one day.

Amantadine and rimantadine have activity against influenza A, but not B. Rimantadine has lower incidence and severity of central nervous system side effects than amantadine. Zanamivir and oseltamivir are active against both influenza A and B. None of these agents interacts with T.F.'s immunosuppressive therapy. I'd recommend holding furosemide to prevent dehydration.

With T.F.'s influenza A diagnosis and renal insufficiency, I'd suggest oral rimantadine 100 mg twice daily for five days. If flu species is uncertain, I'd recommend oral oseltamivir 75 mg twice daily for five days.
Xiaolan Liang, Pharm.D., BCPSClinical PharmacistUniversity of Wisconsin Hospital & ClinicsMadison, Wis.