Illustrative examples of some problems with naming drugs are in the links at the bottom of this post. Of relevance here are the US patent-protected brand name and the international nonproprietary name. My specific example is an antibiotic with the brand name Vibramycin and the INN doxycycline hyclate. Since it is currently in short supply, The American Society of Hospital Pharmacists, which tracks drug shortages, has conveniently listed all the manufacturers on this web page. Towards the bottom you will note that Pfizer is still making the brand name product, even though the patent monopoly is no longer in effect. Various health care personnel in the US system will refer to this drug in writing and orally as Vibramycin despite the fact that it is unlikely they are dispensing the Pfizer product. On the contrary, a hospital purchasing system will buy the least expensive product they can obtain from one of numerous other manufacturers you see listed.
So, I find this irritating, this implication that you are receiving a brand name version of a drug rather than the cheapest available generic version. If you read labels in the hospital, you can see for yourself that this is true, and I am sure you are aware that there is rarely a significant difference in efficacy between a brand name product and its generic clone. There are exceptions, a couple are discussed in the posts below.
Like Ms. Brown and Dr. Schumann, I also find the naming systems confusing, though for different reasons. For two decades I edited English translations of a wide variety of medical documents from many multinational corporations. Because of the international nature of these documents, the INN was the standard used. The INNs predominated and trade names mainly appeared in patents, patent litigation and marketing documents, so I am altogether unaware of many trade names. I would much prefer consistent use of INNs to avoid my own confusion and that of other health personnel. The INN system for selecting drug names seems much more systematic than those for selecting brand names, which vary by country. Not that the INN system doesn't need considerable improvement. Keep scrolling down the ASHP web page to the heading Related Shortages and go down the list until you come to the INNs that start with cef-. How would you like to make the attempt to keep those straight in your head? If you've lived long enough to need an antibiotic for something, you might also be aware that there are other INNs that begin with ceph-. Since cef- and ceph- are pronounced the same way in English, here is another possible source of error.
One Drug, Two Names, Many Problems - Theresa Brown (If you don't subscribe to the NYT, you can open this link in a Google Chrome incognito window or a Firefox new private window.)
GENERICS - by John Henning Schumann, who curates The Glass Hospital blog.