Guaifenesin is also a centrally acting skeletal muscle relaxant. Guaifenesin has antitussive effects, it can inhibit the cough-reflex sensitivity in acute viral cough, it is an expectorant commonly by thinning the mucus or phlegm in the lungs.

5-hydroxytryptophan is a tryptophan derivative that is tryptophan substituted by a hydroxy group at position 5. It has a role as a neurotransmitter and a human metabolite.

N-[(7S)-1,2-dimethoxy-10-(methylthio)-9-oxo-3-[[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)-2-oxanyl]oxy]-6,7-dihydro-5H-benzo[a]heptalen-7-yl]acetamide is a glycoside.