Every medication comes to the market with two names, and these are generic and brand names, respectively. The brand name is the one that is most well known to the public, and the generic is the name that the drug is born with and is given a brand name when it comes to market.
When a medication is given a brand name, it is patented with that name, and once the patent lapses, other companies are permitted to replicate the drug with the generic name. There can be a difference in the composition of the generic medication produced aftermarket brands. There are some medications that physicians prefer to prescribe as brand necessary because certain levels may not be the same in the generic version.