Prescription Audit and Dispensing Errors in the Outpatient Pharmacy of Tertiary Care Multispecialty Teaching Hospital

Background: Although errors occurring during the process of dispensing may affect the goal of the treatment, they also can be the significant cause of morbidity and mortality. There are only few published evidences which focuses on the errors of dispensing that occurs in the pharmacy. This study focuses on identifying the dispensing errors, impact of brand substitution on cost and DDIs. Objective: To identify the dispensing errors, impact of brand substitution on cost and DDIs. Methodology: Prospective observational study conducted over a period of eight weeks in outpatient hospital pharmacy of tertiary care multispecialty teaching hospital, Tamil Nadu. Prescriptions and medication bills and dispensed medicines are collected from the hospital pharmacy to obtain data required for the study. Prescription containing only medical devices were excluded from the study. Results: Out of 1010 prescriptions, dispensing errors were present in 419 (41.48%) prescriptions which consist of 557 errors. The errors include dispensing multi-pills to make the required dose is 3.77%,tablet splitting is 0.8%, incorrect strength is 1.07%, omission error due to unavailability is 31.4%,dispensing drugs with brands other than prescribed brands is 63.7%. Prescriptions which had more than three drugs were analyzed for drug-drug interactions (n=389). DDIs were present in 156(40.1%) prescriptions which had a total of 281 interactions. Conclusion: The brand substitution and omission errors are the major causes of dispensing errors. Brand substitution is not always recommended as it may have some adverse effects because of salt and excipients variation. Pharmacists are in the position to identify and reduce DDIs by discussing with the physicians.