Generic and brand name drugs have identical active ingredients, and generic drugs must meet Health Canada’s standards for bioequivalence. Bioequivalent drug formulations have the same bioavailability; that is, the same rate and extent of absorption.
Although the active ingredients are the same, the excipients (inactive ingredients) may differ. This is only important in rare cases when a patient has an allergy or sensitivity to one of the excipients.
The product may also be slightly different in colour, shape, or markings.
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Biosimilars, on other other hand, is a drug demonstrated to be highly similar to a biologic drug that was already authorized for sale. Biosimilars are not the same as generic drugs. Generic drugs are small molecules that are chemically synthesized and contain identical medicinal ingredients to their brand name reference products. Due to the size, complexity and natural variability of biologic drugs, and because biologic drugs are made in living cells rather than with chemicals, a biosimilar and its reference biologic drug can be shown to be similar, but not identical.