NAC is a pharmaceutical approved since the 1960s, originally sold as Mucamist to thin respiratory mucus. Its main clinical use today is as the high-dose antidote for acetaminophen overdose, given intravenously to prevent liver and kidney damage from the drug's toxic metabolite.
N-acetylcysteine is a drug also. So why would they have a drug that was an amino acid? They've had the drug since about 1963, I think, or '64, and used to have a trade name called Mucamist. So mucus like Mucamist, and the mist part was it was often used in nebulizers. When you look at the drug use of N-acetylcysteine, Mucamist, it's not as famous for respiratory disease as it is for rescuing people who have taken too much Tylenol, acetaminophen. So the antidote to acetaminophen poisoning is high-dose N-acetylcysteine, given usually intravenously to help the kidney damage that the acetaminophen caused in the liver.
