Background and importance Oseltamivir is used in the treatment of influenza A. In our organisation, there is a protocol with recommendations for use. It is only indicated in patients with positive polymerase chain reaction (PCR) influenza A. The recommended duration is 5 days and the dosage should be adjusted in cases of renal failure: 75 mg/12 hours (glomerular filtration rate (GFR) ≥30 mL/min), 75 mg/24 hours (GFR=10–30 mL/min) and 30 mg/24 hours (GFR ≤10 mL/min or haemodialysis).

Aim and objectives To assess compliance with the recommendations for use of oseltamivir in two hospitals of our organisation (H1 and H2).

Material and methods This was an observational and retrospective study (December 2018–April 2019). Patients treated with oseltamivir in H1 and H2 were included.

Inclusion criteria: age >18 years, hospital admission.

Exclusion criteria: critical care admission, transfer to another hospital and discharge prior to finalising treatment.

Collected data age, gender, oseltamivir indication (positive PCR influenza A or empirical treatment), dosage, duration and PCR influenza A result.

Results A total of 251 patients were included, mean age 78 (SD 14.4) years, 55% women.

In 65% of patients, treatments were initiated after a positive PCR influenza A result. In 35%, treatments were empirical; 95% of empirical treatments were from H2 where there was a 24–48 hour diagnostic delay compared with H1 (1–2 hours).

Duration of the treatment was 5 days in 35% of patients, ≥6 days in 22% and ≤4 days in 43% (78% of short treatments were empirical and were stopped after a negative PCR influenza A result).

Correctly adjusted treatments according to recommendations were 74%. Unadjusted treatments were underdosed in 93% and overdosed in 7%.

Conclusion and relevance In our study, there was a high percentage of empirical treatments. This could be decreased by having early diagnostic in all hospitals. Duration of treatment was adequate according to the protocol in only one third of patients. A set duration of treatment in the electronic prescription system could increase this number. Most treatments were adjusted to the recommended dosage. Unadjusted treatments were mostly underdosed. Training for professionals is necessary to explain the recommendations again.

References and/or acknowledgements No conflict of interest.