Pro re nata (PRN) prescription is a frequently used prescription method in hospitals. This study was conducted to investigate actual condition of PRN prescription and whether administration error occurred because of perception difference between doctors and nurses.

From May to July 2012, a survey was conducted among 746 doctors and nurses (88 doctors and 658 nurses) working at 5 hospitals located in Seoul, Gyeong-gi, and Gangwon Province. Doctors generating PRN prescription responded to actual conditions of PRN prescription and both doctors and nurses reported whether administration error occurred due to perception difference.

Average number of PRN prescription of surgical residents was 4.6 ± 5.4, which was larger than that of medical residents (1.7 ± 1.0). Surgical residents more frequently recorded maximum number of daily intake (P = 0.034) and, although not statistically significant, more often wrote exact single dosage (P = 0.053) and maximum dosage per day (P = 0.333) than medical residents. Doctors expected nurses to notify them before the administration of medication; however, nurses were more likely to conduct PRN administration by their own decision without informing doctors. In addition, some doctors and nurses experienced administration errors because of it.

Standard prescription methods need to be established since there is a perception difference in PRN prescription between doctors and nurses and this could be related to administration errors.