Patterns of use for brand-name versus generic oral bisphosphonate drugs in Ontario over a 13-year period: a descriptive study.

BACKGROUND: Bisphosphonates are the first-line therapy for the treatment of osteoporosis. In the province of Ontario, the Ontario Drug Benefit Program funds medications for patients aged 65 years and older. The Ontario Drug Benefit Program has a generic substitution policy that requires lower-cost generic drugs to be dispensed when they are available. However, there is controversy surrounding the efficacy and tolerability of generic bisphosphonates. The objective of this study was to describe patterns in the use of brand-name versus generic formulations when dispensing oral bisphosphonate over a 13-year period.

METHODS: We identified all osteoporotic preparations for alendronate and risedronate that were dispensed through the Ontario Drug Benefit Program from 2001 to 2014. We stratified our sample into community-dwelling residents and residents in long-term care facilities. The number of prescriptions dispensed per month were plotted to illustrate trends over time.

RESULTS: We found a rapid switch from brand-name to generic bisphosphonate equivalents immediately after the generic became available on the Ontario Drug Benefit formulary, with generics accounting for > 88% of dispensed drug within 2 months. We also observed a reduction in the number of generic drugs dispensed each time a new brand-name alternative (e.g., monthly risedronate, weekly alendronate plus vitamin D) was introduced to the formulary. The dispensing trends were similar in the community and long-term care settings.

INTERPRETATION: The Ontario Drug Benefit Program generic substitution policy resulted in rapid uptake of generic oral bisphosphonates among seniors in Ontario. However, there was a switch away from generic medications to new brand-name alternatives whenever they were introduced to the formulary. Therefore, some patients continued to use brand-name bisphosphonate despite the availability of generic options.