Pethidine and Meperidine are both the same substance, known under the brand name Dolantine in Europe and most of the rest of the world, and as Demerol in North-America. Meperidine is not UNAN, but USAN, USAN stands for United States Adopted Name, INN stands for International Nonproprietary Name. The whole world just calls it Pethidine, which it was named by Sanofi-Aventis who invented it. America though, for some reason, calls it entirely different, Meperidine instead of the international Pethidine. Another example is Paracetamol, which is it's INN, it's USAN though, is Acetaminophen, which is how it's called in America. Reminds me a bit of Brittain, driving on the left side of the road and using the imperial system, while the European continent drives on the right and uses the metric system.
The Americans did the same thing with the brand names of many pharmaceutical drugs as well, for instance the majority of benzodiazepines, much of the opioids as well as much of the antidepressants, causing misunderstandings when they are discussed here on the forum when only their brandnames are mentioned. If an Italian member is treated for anxiety issues by his doctor with Lorazepam, which fails to do a good job at preventing panic attacks, which he discusses on the forum, an American member would probaply have difficulties understanding why the Temesta the Italian is prescribed isn't working. And if the Italian mentions he was prescribed Oxazepam before the Lorazepam, the American won't have a clue about what's being discussed either, when the Italian tells him kindly that he used to be prescribed Seresta, before the Temesta. For that reason, everyone should include the drug's name as well(preferrably in brackets behind the brand name), when using brand names too.