In a report tabled in the National Assembly Thursday, Salois said a new plan needs to be put in place.
Salois said the list of medications covered by the province's basic prescription drug insurance plan has never been reviewed. He said some medications on the list could be replaced by others that are cheaper and more effective.
Salois's report said 55 per cent of Quebecers regularly use prescription drugs — a greater number than in the rest of Canada.
In 2014, prescriptions in both public and private plans cost the province a total of $7.7 billion. That represents 17 percent of Quebec's total health care budget.
"We prescribe more. In the end, it's more expensive for medication here in the province of Quebec than in the rest of Canada," Salois said.
Health Minister Gaétan Barrette said Thursday that he's on the same page as the commissioner.
"In my view, there is absolutely no doubt that we pay too much for generic medication in Canada and certainly in Quebec," Barrette said.