During the H1N1 (swine flu) pandemic of 2009, the World Health Organization 
(WHO) confirmed more than 14,000 deaths globally; this included a death toll of 
147 in Iran. In order to evaluate (a) the appropriateness of the Oseltamivir 
dose through calculation of a patient’s creatinine clearance (CrCl) and (b) the 
quality of data in the medical charts, we conducted a retrospective study at the 
Shariati Hospital in Tehran. All admissions to the hospital between the dates 1 
October 2009 and 31 January 2010 were evaluated, amounting to a total of 51 
patients’ charts, including 8 outpatient charts. Of these 51 charts, 26 (51%) 
contained all the information necessary to evaluate the CrCl. However, there was 
at least one piece of information missing (e.g. the patient’s weight; serum 
creatinine) from each of the remaining 25 charts (49% of the sample), which made 
it impossible for us to evaluate the dose. These results demonstrate how 
crucially important it is to ensure that all the necessary patient information 
is correctly registered at the time of admission in order to minimise medication 
errors.