The purpose of this study was to assess the quality of interdisciplinary medical-pharmaceutical interventions, from a cost-benefit analysis of the medical prescriptions of statins and fibrates in a state public health unit that dispenses specialized high-complexity drugs. This is a prospective longitudinal intervention study, involving 502 patients, of the period January-September 2009. Most prescriptions issued for the treatment of dyslipidemia in 2008 included atorvastatin (72.3%) and the annual cost of the drug was approximately R$ 1.9 million. In the cost-benefit analysis, 272 (54%) prescriptions indicated atorvastatin as the first therapeutic choice drug. After the interventions, 81% of the problems encountered were resolved, in general, by interdisciplinary medical-pharmaceutical actions. The interventions led to significant changes in prescriptions, reduced spending on pharmacotherapy and great savings for public coffers. [ABSTRACT FROM AUTHOR]