BACKGROUND: The excessive use of ?-agonist medications by asthmatics has been identified as a significant risk factor for increased morbidity and mortality. The objective of this analysis is to evaluate -agonist users in BC to determine if -agonist utilization is decreasing, as recommended by current asthma management guidelines. METHODS: Asthma medication prescription records were obtained from BC Pharmacare for all patients in BC covered by Pharmacare who received at least one prescription for a ?-agonist medication in 1996, 1997, and 1998. Annual -agonist use was standardized to salbutamol 100mcg, 200 doses/canister. Cross-sectional and longitudinal analyses were undertaken to identify potential trends in the excessive use of ?-agonist medications. RESULTS: Data from 13,481 patients covered by Pharmacare PlanC (social assistance first dollar coverage) or PlanE (individuals or families exceeding deductible) were analyzed. In 1996, 1,898 patients (14.1%) were high users of -agonists (>12 canisters/yr) in 1996 compared to 1,686 (12.5%) in 1998 (p=0.001). 1,119 patients (59%) who were high users in 1996 remained high users in 1998, 38.7% of which continued to use >20 canisters/yr. Of those patients using ?12 canisters in 1996, only 4.9% increased their use to >12 canisters/yr in 1998. 116 patients prescribed ?4 canisters in 1996 substantially increased their use to >12 canisters in 1998. Age was positively associated with the number of canisters prescribed (r=0.21;p=0.001); only 4% of patients <19 years used >12 canisters in 1998 compared to 16% of patients ?19 yrs. Age was also associated with increasing use over the 3 years (p=0.001). CONCLUSIONS: This analysis suggests a trend in asthma management towards decreasing ?-agonist use. However, >10% of ?-agonist users in this population continued to use excessive or increasing amounts of -agonists despite current treatment guidelines, putting them at greater risk for ?-agonist related morbidity and mortality, and increased health care utilization.