Canada's provincial governments have, until relatively recently, provided virtually all seniors with generous prescription drug coverage. Managers of these programs have implemented a variety of policies to contain spending while ensuring access to necessary medicines. Some of these policies have been successful in temporarily slowing cost growth. However, the lack of comprehensive utilization management tools has resulted in ongoing spending increases that now constitute a threat to the sustainability of a public drug subsidy for Canadian seniors. Sustainable and equitable pharmacare programs require the political willingness to confront opposition to policies that will, if successful, contain program costs without obstructing access.