Overview Guaifenesin (Robitussin) removes excess sputum does not suppress cough reflex must use large doses N-acetylcysteine mucolytic cleaves disulfide bridges between mucus glycoproteins loosens mucus plugs in CF patients also used as an antidote for acetaminophen overdose Dextromethorphan over the counter cough suppressant side effect of constipation overdose can lead to hallucinations