Background Due to the nature of emergency department, quantity of medicine used and starting of a newly established emergency medicine residency program in our hospital it was decided to use clinical pharmacist interventions to protect patients from adverse drug events.

Purpose To assess clinical pharmacist intervention impact on reduction of medication errors.

Materials and methods Retrospective evaluation orders of emergency medicine residents from October 2010 to January 2011 were done. The frequency of prescription errors determined by a clinical pharmacist based on patients medical records. Subsequently, weekly educational sessions on prescribing for emergency medicine residents conducted by a clinical pharmacist. Recording errors continued for 4 months period prospectively and statistical analyses compared the results before and after interventions.

Results In a retrospective study The authors evaluated 5320 prescription with total number of 22346 medication ordered. Results indicated 4941(22.1%) ordering errors. After clinical pharmacist intervention the rate diminished significantly to (5.6%) 1276 errors in 5602 prescriptions (22743 medication orders) (P<0.01). Inappropriate drug choice (23%), improper dose(21%), inaccurate dosing interval(19%), drug interactions(16%), misdiagnosis(14%), choosing wrong dosage form(4%), and improper route of administration(3%) were errors before clinical pharmacist interventions. The most frequent errors after intervention were inappropriate drug choice (20%), and drug interactions (18.5%). The rate of other kind of errors were in this order: misdiagnosis (18%), improper dose (18%), inaccurate dosing interval (15.5%), choosing wrong dosage form (6%), and improper route of administration (4%). Inaccurate dosing interval decreased more than other prescribing errors with pharmacist intervention (from 939 to 198 errors).

Conclusions The results show that reduction in prescribing errors was significant after pharmacist intervention. Monitoring of orders and drug therapy education of the physicians seems to be a substantial factor in hospitals which lead to patient safety and rational drug use.