OBJECTIVES: The aim of this paper was to examine trends in expenditure of pharmaceuticals on the community drug schemes from 2005 to 2010, during which time a range of cost-containment interventions were introduced which affected the pricing mechanism for pharmaceuticals in Ireland. METHODS: Data were analysed using a national prescription claims database according to drug class, i.e. generic, patent and off-patent for the two largest schemes; the General Medical Scheme (GMS) and Drug Payment (DP) scheme. Segmented regression was used to analyse the effects of the interventions on expenditure. RESULTS: An increase in expenditure was noted across all schemes up to 2009 and declined thereafter to the end of the study period (October 2010). Significant reductions in expenditure were noted following the introduction of a 20% price-cut to patent-expired products (off-patents) (p<0.001). In July 2009, pharmacy and wholesale margins were reduced, resulting in significant reductions in expenditure for patented (GMS; p<0.05 and DP scheme; p<0.001) and generic (DP scheme only; p<0.01) products. No significant reductions in expenditure were noted for off-patent products at this time. Furthermore, no significant reductions in expenditure were noted for off-patents following a 15% price reduction in January 2009 and a further 40% price reduction in February 2010. CONCLUSIONS: Results from the study indicate that reductions in the wholesale margin and pharmacy mark-up had the largest impact on reducing pharmaceutical expenditure during the study period. This analysis of national expenditure trends over a six-year period provides valuable information for the healthcare payer on the impact of the cost-containment interventions and may provide a benchmark for future negotiations with the pharmaceutical industry.