ABSTRACT Background According to international research, an increase in the patient share of pharmaceutical expenditure results in a decrease in medicines utilization. In 2010, the Portuguese government reduced the reimbursement rate for certain therapeutic classes. The aim of this study was to evaluate the impact of raising cost to the patient on the utilization of medicines. Methods Between January 1996 and December 2015, medicines utilization and cost to the patient per DDD of antihypertensive, antidyslipidemic, antidiabetic, antiulcer and antidepressant medicines were compared. A segmented linear regression of two time series – before and after the change in reimbursement percentage – was used. Results During the two time series, there was an increase in the utilization of antidepressants and antiulcer medicines. The consumption growth decelerated following the reduction in reimbursement rate. Cost to the patient decreased for both classes across the two time series, although the trend accelerated during the second. Conclusion These findings suggest that a decrease in the reimbursement rate had little impact on the utilization of medicines. It is reasonable to assume that the reduction in percentage covered by the Portuguese National Health System was gradually compensated by the decrease in the absolute amount that patients paid for medicines.