Preferential listing of a PPI: Compliance with policy in a Canadian military population

Preferential listing of a single drug is a common strategy for controlling costs within a drug class. In 2003, the Canadian Forces (CF) drug benefit plan used preferential listing to control costs associated with proton pump inhibitors (PPIs). However, significant expenditures for nonbenefit PPIs continued. A database review was thus conducted to explain this anomalous usage pattern. Pharmacy claims for PPIs were reviewed for CF members who received >= 1 PPIs between 2002 and 2005. Documentation entered by pharmacists at the time of prescription processing was also reviewed. A total of 4,738 PPI users were identified, of whom 87% were using the preferred drug. Failure to respond was the most common reason for use of nonbenefit PPIs (79.4%), whereas side effects were documented in only 8.3% of such users. This study provides further information regarding the effectiveness of preferred listing as a cost-saving measure, noting that adherence to such policies may be less than projected. Our work also demonstrates the utility of pharmacists' notes for purposes of drug use evaluation, (Formulary. 2008;43:436-444.)