OBJECTIVES: In October 2010, the Irish healthcare payer (i.e. the Health Service Executive, HSE) introduced a €0.50c charge on all prescription items dispensed under the General Medical Services (GMS) scheme, the largest of the community drug schemes in Ireland covering approximately 40% of the population. We investigated whether this charge was associated with changes in drug utilisation. METHODS: Monthly prescription dispensing was analysed from September 2009 to September 2010 (pre-intervention period) and then from November 2010 to March 2011 (post intervention period). In addition to utilization (prescription items) and cost information the database classifies drugs according to whether they are generic, off-patent or patent. The volume of drugs dispensed in each class was calculated and trends in utilsation and expenditure from the pre intervention period were compared with those in the post intervention period using segmented regression analysis. All analyses were performed using SAS (v9.1, SAS Institute Inc. Cary, US). Statistical significance at p<0.05 is assumed throughout. RESULTS: No effect was noted following the introduction of the prescription charge on prescription items in the post intervention period. A decrease in ingredient cost was noted however, for generics in the month post the intervention (p<0.01). A change in the overall trend for ingredient cost of off-patents was noted also in the post intervention period (p<0.05). The intervention had no significant effect on utilization and expenditure of patented medicines. CONCLUSIONS: The study findings suggest that the recent introduction of a prescription charge has had no significant effect on utilization of prescription medicines, while decreased expenditures could be attributed to changes in the pricing mechanisms for generics and off-patents occurring around this time. Further analysis is warranted to determine if the effect on utilization is sustained over time.