Usually 20 years. A drug patent expires 20 years from the date on which the patent application was filed in the United States. Sometimes, a term extension is provided if the original patent was delayed due to secrecy orders, interferences, or appellate review periods. Generics can be launched once the patent-protected drug surpasses the patent expiry and exclusivity date. Elixir provides the drug patents list expiring in a particular year, like 2023, 2024, and more.