Background Our 450-bed general hospital had a unit dose dispensing system in 100% of inpatient wards until July 2010, when an automated dispensing system (ADS) incorporating most of the medicines was introduced in the Large Burns Unit (LBU).

Purpose To quantify the variation in drug expenses allocated per patient after introduction of an ADS in the LBU and to identify the products mainly affected by this change. Materials and Methods To quantify the variation in the expenses allocated, The authors compared two equal periods of four months, before the introduction of the ADS (September-December 2009) and four months after (September-December 2010). The authors used the average book price to calculate the cost of the Unit, by adding the cost of stock replenishment and unit dose medicines dispensed in the case of the first period and extracted from the ADS in the case of the second period.

Results In the period prior to ADS implementation, Unit expenses were 53,037 euros of which 45.43% were allocated to the patient. After ADS implementation, the Unit cost 50,732 euros to run, of which 73.33% were allocated per patient. Of the 68 products that went from dispensing stock to ADS, the ones that mainly affected the change in the medicines expense allocation per patient were: sulfadiazine (47.5%), midazolam (8.5%) atracurium (5.8%), propofol (5.5%) and ketamine (4.3%).

Conclusions The medicines that mainly affected the change in the allocation of medicines belong to the D06, N05, M03 and N01 ATC classification groups in financial terms:, these were traditionally dispensed by replenishing stock. This has represented a significant reduction in the Unit stock. The ADS improve the allocation per patient of medicines expenses, including special units with prior unit dose dispensing, which enables the pharmacist to increase the level of knowledge about drug use in the Unit.