History of aspirin Hermann Hildebrandt). In 1894, the young chemist Felix Hoffmann joined the pharmaceutical group. Dreser, Eichengrün and Hoffmann would be the key figures in the development of acetylsalicylic acid as the drug Aspirin (though their respective roles have been the subject of some contention). In 1897, Hoffmann started working to find a less irritating substitute for salicylic acid. It is generally accepted that he turned to this idea because his father was suffering the side effects of taking sodium salicylate for rheumatism. In 1853, Charles Frédéric Gerhardt had published the first methods to prepare acetylsalicylic acid. In the course of his
4-Aminosalicylic acid because aminosalicylic acid inhibits the synthesis of thyroid hormones. Drug interactions include elevated phenytoin levels. When taken with rifampicin, the levels of rifampicin in the blood fall by about half. The U.S. FDA assigned PAS to pregnancy category C, indicating that it is not known whether it will harm an unborn baby. With heat, aminosalicylic acid is decarboxylated to produce CO and 3-aminophenol. PAS has been shown to be a pro-drug and it is incorporated into the folate pathway by dihydropteroate synthase (DHPS) and dihydrofolate synthase (DHFS) to generate a hydroxyl dihydrofolate antimetabolite, which in turn inhibits dihydrofolate reductase (DHFR)