Background Automated Dispensing Cabinets (ADC) offer several benefits to the organisation and the user. They provide nurses with near total access of medications, ensure greater control of medications and reduce medication errors. It was necessary to evaluate in which way the ADC could potentially reduce the drug consumption on the ward.

Purpose To estimate the return on investment (ROI) of an ADC taking into accounts only the reduction in drug consumption.

Materials and methods The drug consumption in two wards of similar characteristics of internal medicine was compared in a tertiary hospital. The ward used as a control did not have an ADC and distribution of medicines was made from ward stock. The test ward made use of an ADC model OmniSupplier. An inventory of the medicines in both wards was made on January 10th, 2010. During a one year period 323 drugs were monitored in both wards, and the drug consumption data analysed and compared.

Results Two wards were selected with 29 patients each. The drug consumption during the one year period in the control ward came to 87.210 Euros, whereas the total cost of the test ward was 73.001 Euros. This represents a difference of 13.719 Euros (16,3% reduction) in drug consumption. The value of the stock in the control ward was 7.802 Euros, while the value of the test ward was 3.392 Euros, with a median stock reduction of 56,5%±21. Overall, when comparing the results obtained from the two wards, a consistent reduction is observed in almost all medicines. In some medications and dosage forms, the reduction of consumption was more significant for example oral analgesics, oral penicillins, simvastatin, antacids/gastric protectors and oral mucolitic drugs. At our hospital, the cost of the ADC, as configured, was approximately 55.000 Euros (costs of ADC's are dependent upon the number of drawers and hardware configuration and start at approximately 25.000 Euros) plus a maintenance contract of around of 3.000 Euros per year. Taking into account only the reduction in drug consumption, if The authors consider a 5 year maintenance contract, the cost of the ADC would be 70.000 Euros. If The authors divide this by the 13.719 Euros of the reduction in drug consumption, then an ADC could be payed off in about 5 years.

Conclusions The investment for the installation of the ADC can be justified on the reduction in drug consumption on the war.