Acetylcysteine is for inhalation (mucolytic agent) or oral administration (acetaminophen antidote), and available as sterile, unpreserved solutions (not for injection). The solutions contain 20% acetylcysteine with 0.05% edetate disodium, or 10% acetylcysteine with 0.025% edetate disodium, in Water for Injection. Sodium hydroxide and/or hydrochloric acid may be used to adjust pH to 6.0-7.5. Acetylcysteine is the N-acetyl derivative of the naturally occurring amino acid, cysteine. The compound is a white crystalline powder with the molecular formula C5H9NO3S, a molecular weight of 163.2, and chemical name of N-acetyl-L-cysteine.