Outside hospitals, drug therapy is not universally insured by the Canadian public health care system. Coverage depends on choices made by the provincial and territorial governments in designing their pharmacare programs. A priority within the programs is ensuring that all Canadians have reasonable access to catastrophic drug coverage. However, the best way to provide this coverage is by no means clear. This commentary reviews evidence and experience from other countries in order to assess the options for a few key dimensions of expanding pharmacare coverage. These are: eligibility rules for individual coverage; drug assessment in terms of approval for coverage; medication management strategies; and finally ongoing program evaluation. Catastrophic drug coverage needs to be flexible to adapt to existing pharmacare programs and responsive to the competing demands for limited resources within the health care sector.