The actions of judicialization in pharmaceutical care, within the scope of rare diseases, have generated exorbitant expenses to the Unified Health System (SUS) of Brazil. In 2016, SUS spent R$18,6 billion on medicines.

OBJECTIVES: to estimate the cost of the judicialization of biological medicines used in rare diseases in the State of São Paulo - SP, Brazil.

METHODS: Descriptive study whose data were obtained from administrative banks of the State Department of Health of São Paulo, in the year 2017. Variables related to the number of actions demanded, consumption of drug units, estimated monetary value per share. Descriptive statistics were used.

RESULTS: A total of R$ 49.234.463,00 / month was spent in the general analysis of the 50 drugs involved in the most costly actions to cover 10,985 patients, representing an average cost of R$4.481,97 per patient per month. Of this group, 16% of the actions involved biological drugs (Eculizumab, Galsulfase, Idursulfase, Betagalsidase, Alfalglicosidase, Laronidase, Miglustate, Translarna, Azacitidine) used in 168 patients with rare diseases, which totaled 27.5% of the cost and generated a cost monthly average per patient of R$80.722,1 representing 18 times higher than the estimated cost in the general analysis. Eculizumab was the most expensive, accounting for 42.3% of the monthly biological expenditure, with an average of R$136.687,34 per patient per month.

CONCLUSIONS: The significant amount made available for the acquisition of medicines by judicialization, especially biological ones, could jeopardize the financial resources made available to the SUS, particularly serious in the situation of budget constraint instituted by governmental measure No. 95/2016.