Rimantadine antagonistic properties and is used as an antiparkinsonic drug (i.e., in the treatment of Parkinson's disease). However, in general, neither rimantadine nor amantadine is a preferred agent for this therapy and would be reserved for cases of the disease that are less responsive to front-line treatments. Taking paracetamol (acetaminophen, Tylenol) or acetylsalicylic acid (aspirin) while taking rimantadine is known to reduce the body's uptake of rimantadine by approximately 12%. Cimetidine also affects the body's uptake of rimantadine. Rimantadine can produce gastrointestinal and central nervous system adverse effects. Approximately 6% of patients (compared to 4% of patients taking a placebo) reported
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)