Objectives: To assess and compare the unit cost of inpatient prescriptions between manual and automated dispensing machine (ADM) systems.

Methods: The unit cost per prescription was calculated using a standard or conventional method for the inpatient department of the 2,100-bed university hospital. The unit cost calculation was comprised of five steps including 1) identifying and classifying cost centers into transient cost center (TCC) and absorbing cost center (ACC); 2) determining all direct costs that covered the labor cost (LC) of medical staff and supporting staff, material cost (MC), and capital cost (CC); 3) allocating indirect costs from TCCs to ACCs using a direct method; 4) adding up direct and indirect costs of each ACC; and 5) calculating the unit cost per prescription of the inpatient service by dividing the total cost of the inpatient service by the number of prescriptions. The additional indirect cost of cost centers outside the pharmacy department was added to the unit cost at the rate of 10%. All costs and the number of prescriptions were in fiscal year 2014. A sensitivity analysis was conducted to estimate the unit cost at different scales if the system was expanded.

Results: The total costs of the inpatient service under 100% manual and ADM systems dispensing 22.8% of inpatient prescriptions were 82.7 and 89.8 million baht/year, respectively. The unit cost of inpatient prescriptions using the ADM system was 60.34 baht/prescription, which accounted for 8.5% higher than 55.59 baht/prescription of the traditional manual system. The proportions of LC:MC:CC for the manual and ADM systems were 87.8:12.1:0.1 and 88.0:9.3:2.8, respectively. The sensitivity analysis result illustrated that the lower unit cost could be achieved if the ADM system covered at least 75% of all prescriptions. At the 75% coverage, the unit cost was 53.95 baht/prescription and the proportion of LC:MC:CC was 83.6:13.3:3.1.

Conclusion: Dispensing using the ADM system required higher investment than the traditional manual system on the capital cost of ADM machine and equipment. The hospital would benefit from the lower unit cost per inpatient prescription if the ADM system dispensed beyond 75% of all prescriptions.