Generic drug is bioequivalent to a brand name drug, but are sold as much lower price. It has the same ingredients, same dosage forms and strengths as the brand drug. It is used and affected the body in the same way and has the exact same side effects as the brand drug. Therefore, generics are assumed to be identical in dose, strength, route of administration, safety, efficacy, and intended use.

So why do medicines have more than one name?
. Generic name is the active ingredient of medicine
. Brand name is the trade name given by the manufactures.

For example would be Viagra is well-known brand name give by Pfizer to the generic sildenafil. Brand name is being designed on the idea that it can be easily recognized, pronounced and remembered by all member of professional and public.