Changes in long-acting β-agonist utilization after the FDA's 2010 drug safety communication.

Purpose: In February 2010, the US Food and Drug Administration (FDA) issued new recommendations for the safe use of long-acting β-agonists (LABAs) in patients with asthma. The objective of this study was to determine the impact of the FDA's 2010 safety advisory on LABA utilization.

Methods: Using administrative data from the Oregon Medicaid program, we performed an interrupted time series regression to evaluate changes in the trend in new LABA prescriptions before and after the FDA's 2010 advisory. Trends in incident fills were examined among those with and without an asthma diagnosis code and previous respiratory controller medication use; trends were also assessed according to patient age.

Findings: The average age of the 8646 study patients was 37 years, 53% had a diagnosis of asthma, 21% had no respiratory diagnosis, and 32% had not used a respiratory controller medication in the recent past. The trend in new LABA prescriptions declined by 0.09 new start per 10,000 patients per month (95% CI, -0.19 to -0.01) after the FDA's advisory. Among those with a diagnosis of asthma, there was an immediate drop of 0.48 (95% CI, -0.93 to -0.03) and a 0.10 (95% CI, -0.13 to -0.06) decline in the monthly rate of new starts per 10,000 patients. Immediately after the FDA's advisory, we observed a statistically significant 4.7% increase (95% CI, 0.8 to 8.7) in the proportion of new LABA starts with history of previous respiratory controller medication use. Utilization of LABAs did not change in those without a diagnosis of asthma.

Implications: The FDA's 2010 advisory was associated with modest reductions in LABA utilization overall and in ways highlighted in their recommendations.