Use of oseltamivir in lung transplant recipients with suspected or proven influenza infection: a 1-year observational study of outcomes and safety

Background: Influenza virus infections in lung transplant recipients (LTRs) have an increased risk of unfavourable outcomes. Early initiation of treatment is associated with improved outcomes. In clinical practice, empirical oseltamivir treatment is therefore commonly started prior to diagnostic microbiological confirmation. There is limited data on the patient characteristics, outcomes and safety of this practice. This study investigated outcomes and safety of this pre-emptive treatment strategy using oseltamivir. Methods: Descriptive analysis of LTRs who received oseltamivir for ≥2 days for suspected influenza infection between July 2011 and June 2012. Analyses were based on data from electronic medical records and our standardized LTR database with prospective documentation of clinical information including medication, laboratory and radiological results, outcomes and adverse events. Results: We included 133 patients with a total of 261 oseltamivir treatment episodes (87.4% as outpatients). Median duration of oseltamivir treatment was 4 days (range 2 to 67) and 98.5% had concomitant antibiotic pharmacotherapy. Indications for oseltamivir included acute respiratory infection (66.7%), non-distinctive inflammatory reaction (51.3%) and influenza-like illness (2.7%). Influenza virus infection was confirmed by PCR in only 7%. Rhinovirus was the most frequent pathogen detected (14.9%). We discovered a wide range of adverse events but none occurred in >5%, and most were mild and of questionable causal relationship to oseltamivir administration. Conclusions: This non-controlled retrospective analysis suggests that the pre-emptive use of oseltamivir for respiratory tract infections pending microbiological results is safe in LTRs