How Pharmaceutical Companies Prevent Generics Being Produced?

Once a patent has expired there should be very little
to stop companies producing generic versions of the
original drug.

However companies invest a lot in developing new drugs
so try to extend their exclusivity as long as possible
in a process known as evergreening.

They can in some cases apply for a 5-year extension to
their patent to cover the time they spent developing
and testing the drug and not actually producing and
selling it.

They can also apply for 180 days exclusivity as the
first one to apply and be accepted to produce a
generic version of the original drug.

As well as this there is aggressive litigation against
those who try to produce generic versions in an
attempt to dissuade them; this is costly but not as
costly as the 80% or so price drop of their product
caused by additional competition.

The most common method of evergreening is updating
patents claiming some change in the product and
effectively resetting the clock.

Drug companies also patent every possible thing about
their drug from the colour, size, shape, taste
production method and even the form of compounds used
to make it in order to make it difficult for a company
to produce a generic which does not infringe these
trademarks and patents.