Integration of an actuation counter into pressurized metered-dose inhalers (pMDIs) can allow patients to accurately determine the remaining number of medication doses. This study was designed to assess the functionality of budesonide/formoterol (Symbicort; AstraZeneca, Dunkerque, France) pMDI with an integrated actuation counter in a clinical setting. Children aged > or =6 years, adolescents, and adults with inhaled corticosteroid-dependent asthma participated in this 6-week, randomized, open-label, multicenter study (SD-039-0743; D5896C00743). Patients were treated with budesonide/formoterol pMDI with no actuation counter (80/4.5 micrograms x 2 inhalations [160/9 micrograms] twice daily) during a 7- to 10-day run-in period. Qualifying patients were then randomized into one of three groups treated with budesonide/formoterol pMDI with actuation counter (80/4.5 micrograms x 2 inhalations [160/9 micrograms] twice daily): group 1, 96 actuations (24 days); group 2, 120 actuations (30 days); or group 3, 128 actuations (32 days). Actuation count was assessed using position of the counter arrow, patient/caregiver reports (daily log and actuation counter final reading), and device (canister plus actuation counter assembly) weight change. Patients/caregivers rated ease of device use. There was good agreement across treatment groups (n = 254) between patient/caregiver-reported actuation counts and counts determined by the angular position of the arrow. Analysis of device weight change versus other estimates of actuation counts in groups 1 and 2 indicated that the device did not undercount the number of actuations sprayed. Most patients (93%) indicated the device was "extremely easy" or "very easy" to use. Clinical functionality and reliability of the budesonide/formoterol pMDI device with an actuation counter were established.