When a patent expires, new firms enter the market, and the resulting competition for consumers decreases prices and increases quantities. In the pharmaceutical drug market, when the patent for a brand-name drug expires, other firms introduce generic versions of the drug. The generics are virtually identical to the original branded drug, but they sell at a much lower price. The producers of branded drugs have an incentive to delay the introduction of generic drugs and sometimes use illegal means to do so.

In recent years, the Federal Trade Commission (FTC) has investigated allegations that the makers of branded drugs made deals with generic suppliers to keep generics off the market. The alleged practices included cash payments and exclusive licenses for new versions of the branded drug. In 2003, the FTC ruled that two drug makers had entered into an illegal agreement when Schering-Plough paid Upsher-Smith Laboratories $60 million to delay the introduction of a low-price alternative to its prescription drug K-Dur 20, which is used to treat people with low potassium.

Another tactic is to claim that generics are not as good as the branded drug. DuPont has claimed that generic versions of its Coumadin (a blood thinner) are not equivalent to Coumadin and may pose risks to patients. Because generic versions are virtually identical to the branded drugs, such claims are not based on science.

Question.

What happens when a patent expires and a monopoly ends?