A generic drug (generic drugs, short: generics) is a drug which is produced and distributed without patent protection. The generic drug may still have a patent on the formulation but not on the active ingredient.
A generic must contain the same active ingredients as the original formulation.
According to the U.S. Food and Drug Administration (FDA), generic drugs are identical or within an acceptable bioequivalent range to the brand name counterpart with respect to pharmacokinetic and pharmacodynamic properties.
By extension, therefore, generics are considered (by the FDA) identical in dose, strength, route of administration, safety, efficacy, and intended use.
The FDA's use of the word ''identical'' is very much a legal interpretation, and is not literal. In most cases, generic products are available once the patent protections afforded to the original developer have expired.
When generic products become available, the market competition often leads to substantially lower prices for both the original brand name product and the generic forms.
The time it takes a generic drug to appear on the market varies.
In the US, drug patents give twenty years of protection, but they are applied for before clinical trials begin, so the ''effective'' life of a drug patent tends to be between seven and twelve years.