Objectives - To estimate: a) the number of users of theophylline (ATC: R03DA04) and doxofylline (ATC: R03DA11) for the treatment of chronic asthma and/or COPD in adults, in the Marche Region (Italy); b) the global cost related to the use of the two drugs (associated drugs, specialist visits, hospital admissions, plasma drug monitoring). Methods - The drug prescriptions were extracted from the Information System of the Pharmaceutical Prescriptions of the Marche Region (PHARM), containing all the prescriptions sent by pharmacies within the region and reimbursed by the National Health Service. All the prescriptions for each ATC code in the years 2008-2012 were extracted and the number of prescriptions per year was obtained. The number of subjects receiving >1prescription of the ATC codesR03DA04 and R03DA11 was identified and the number of users was estimated. The concomitant drug number was estimated by selecting all the prescriptions for potentially associated ATCs dispensed 30 days before or after the first prescription of ATC codes. The price of prescriptions was calculated using the information "price" contained in the PHARM record. Results - For both drugs in the study period 13,574 patients were treated with theophylline (94,454 prescriptions) and 19,426 patients with doxofylline (62,791). The number of patients treated was approximately 5,000 per year. Both the number of patients and prescriptions declined during the period of study. The number of prescriptions of theophylline was higher in men, that of doxofylline higher in women. Both theophylline and doxofylline prescriptions increased with the age of patients. Co-prescription with other drugs was lower for doxofylline (1.55) than theophylline (5.50) in the total population (71.7% reduction). In the aged patients the reduction of doxofylline prescriptions versus theophylline was 66%. The use of corticosteroids associated with doxofylline was lower versus theophylline: a) in the total population (0.3 vs 0.7), b) in men (0.3 vs 0.9), c) in women (0.3 vs 0.6) and in aged patients (0.3 vs 0.8; 58.1% less). The mean number of specialist visits was lower in patients treated with doxofylline than in those treated with theophylline in the total population (2.05 vs 3.73), in men (2.38 vs 4.43), in women (1.75 vs 2.95) and aged people (2.52 vs 4.18). The mean number of hospital admissions (per 100 patients) was lower for patients treated with doxofylline than for those treated with theophylline in the total population (1.57 vs 3.3) and in aged people (1.94 vs 3.09). In the total population, the annual mean cost of global treatment per patient was €187.4 for those treated with doxofylline and €513.5 for theophylline, while in the aged people it was €247.7 (doxofylline) and €577.3 (theophylline). Conclusions - The PHARM allows to estimate drug utilization, taking into account the overall patient treatment plan. In our study, compared to theophylline, the prescription of doxofylline was associated less with prescriptions of other drugs, corticosteroids and specialized visits as well as hospital admissions. Therefore, doxofylline resulted to be associated with a reduction of the overall cost of the disease compared to theophylline.