Inter-provincial variation in government drug formularies.

In Canada, coverage for ambulatory prescription drug expenditures is provided to some groups by provincial drug plans through a provincial formulary. Little is known about the drugs provincial formularies give access to. We report the variation in availability of new drug molecules (NDM) across provincial formularies. We identified 108 NDM approved in Canada between 1991 and 1998. From each drug plan bulletin or formulary, we abstracted names of NDM listed as per 15 January 1999. We compared the level of listing across provinces using kappa coefficients. In the Quebec, BC, Manitoba and Saskatchewan formularies, more than 70% of the NDM were listed. In four provinces, this proportion was lower than 50%. In general, the agreement between formularies was poor. There is a wide variation across provinces in terms of NDM listed in the formularies. This variation reflects inter-provincial differences in the way drugs are selected for coverage.