The Food and Drug Administration and Department of Defense were interested in detecting sub-optimal use of long-acting beta-agonists (LABAs) in asthmatics within the Military Health System (MHS). Visualizing the patterns of asthma medication use surrounding a LABA prescription is a quick way to detect possible sub-optimal use for further evaluation. The US Army, Office of the Surgeon General, Pharmacovigilance Center (PVC) selected a random sample of 100 asthma patients under age 65 with a new LABA prescription from January 1, 2006-March 1, 2010 in MHS healthcare claims. Analysis was conducted in EventFlow, a novel interactive visualization tool being developed by the University of Maryland Human Computer Interaction Lab (HCIL) to display and summarize time-point and interval data. EventFlow groups individuals that share the same sequence of medications and displays the average interval times between events. We found that EventFlow was effective in uncovering clinically relevant patterns in the data. Epidemiologists reported that EventFlow was a powerful tool for rapidly visualizing possible patterns of sub-optimal LABA use that can be targeted for intervention.