OBJECTIVES: To estimate the number of users of Theophylline (ATC: R03DA04) and Doxofylline (ATC: R03DA11) for the treatment of chronic asthma in adults, in the Marche Region. Moreover, we wanted to estimate the cost of the two treatments, taking into account the prescriptions of other drugs associated with them. METHODS: The drug prescriptions were extracted from the Information System of the Pharmaceutical Prescriptions of the Marche Region (PHARM), containing all the recipes sent by pharmacies within the region and reimbursed by the National Health System. The number of prescriptions per year has been obtained by selecting all the recipes for each ATC code in the years 2008-2012, while the number of users has been estimated by identifying the subjects who received at least one prescription of the ATC codes of interest. The number of concomitant prescriptions was estimated by selecting all the recipes for potentially associated ATC, dispenced between 5 days before and 5 days following the prescription of ATC codes. The price of prescriptions has been calculated using the information "price" contained in the PHARM record. RESULTS: For both drugs, the users are approximately 5,000 per year in the study period. Theophylline had a mean base price lower than Doxofylline (4.81€ vs 6.37€ per prescription); however, Theophylline was more associated than Doxofylline (34.4% vs 23.7%) with other drugs for the treatment of Asthma. Consequently, the total treatment cost for Theophylline was equal to 33.65€ vs a total cost for Doxofylline equal to 22.49€ (+ 49.6%). CONCLUSIONS: The PHARM allows the estimate of drugs’ utilization, taking into account the overall patient’s treatment plan. In our study, the prescription of the first ATC code is more associated with prescriptions of other drugs, and this implies an increasing in the cost of the treatment plan despite a lower average initial price.