The generic name is assigned by the FDA. It’s given to the drug soon after it’s patented (long before it’s available). Often, it’s just a shortened chemical name (the scientific names are long and cumbersome). The trade name is assigned by the company that makes the drug. Sometimes, they just modify the generic name, sometimes they give it a name that can be associated with what it treats. Sometimes, it seems they just gave it a name.

The chemical name for the drug comes from the chemical structure of the compound, for example:

bis(5-methoxy-2-[(S)-[(4-methoxy -3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-bensimidazole-1-yl) magnesium trihydrate

But that would be difficult to prescribe, so they pick a generic name for the drug, in the above case, esomeprazole magnesium. Bits from the chemical name go into making the generic name. Maybe chemists have a way to naming these drugs so it makes sense to them – I don’t know.

That’s a little easier to deal with, but not real marketable. So the drug companies pick a flashier name that patients can remember – for this drug, it’s Nexium.

The drug name has to pass certain tests – it cannot imply that the drug is better or safer than other drugs, or that it will do something that it doesn’t do. (You could never name a drug “Cure-all”, for obvious reasons). It also cannot look or sound like the name of another drug or medical condition.

Companies then do market research to choose from a variety of names. I’ve done some of that. They ask you to say how you would pronounce the name of the drug, whether it reminds you of other drugs or medical conditions, and whether it implies things. They also ask if the name “represents” what the drug is trying to accomplish, if it sounds safe, etc.

Lots of market research.

I personally think they intentionally make the generic name long and difficult so people will prefer to use the brand name.

How else do you explain “abciximab” vs “ReoPro”?