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Ministry Status: Routine Monitoring and Engagement

Ensuring Better Value for Money

Expanding Interchangeability and Off-Formulary Interchangeability Progress


Pharmacists have always been able to substitute generic products for brand name products that are listed in the Formulary (paid for by the Ontario Drug Benefit program). This is called "interchangeability". The reimbursement of products on the current Formulary is based on a "lowest cost" policy, meaning that pharmacists are required to dispense the lowest cost product listed in a category of drugs (there are some exceptions to this policy). This mandatory substitution, or interchangeability, process is set out in the Drug Interchangeability and Dispensing Fee Act (DIDFA). Under the DIDFA, the interchangeability definition requires that drugs that are considered interchangeable must have the same amount of the same or similar ingredients in the same or similar dosage form ( for example, capsule and tablet).

The Transparent Drug System for Patients Act, 2006 expanded the definition of interchangeability and made it possible for pharmacists to substitute drugs with a similar dosage form (e.g., capsule or tablet) or similar active ingredients. This saves both government and employer drug plans and it saves the consumer who pays cash.

Regulation 201/91 under ODBA and regulation 935 under the DIDFA, sets out the definition for "Therapeutic Substitution." As was always the case, patients will get the specific brand name of a drug prescribed by their physician, in medically necessary circumstances, where a patient has experienced a significant adverse reaction to a generic product, if the physician writes "no substitution" on the prescription and also completes, signs and forwards a Health Canada Report of Adverse Reaction form to the pharmacists.


  • Since October 2006, 86 new generic drugs and 164 new generic drug products have been listed on the Formulary

Off-Formulary Interchangeability

The government has expanded the definition of interchangeability so that it applies to drugs that are not on the Formulary (covered by private plans that are paid for by employers or cash-paying customers). "Off-Formulary Interchangeability" means that less expensive, but equally effective generic drugs can be used in place of brand names, resulting in cost savings for employers and Ontarians.


  • 116 new, multiple source drug products have been listed under the Off-Formulary Interchangeability classification

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