The present invention relates to a solid oral pharmaceutical composition that includes: (a) an active pharmaceutical ingredient; (b) a nitrosamine inhibitor that includes linear or branched C1-C10 alkyl 3,4,5-trihydroxybenzoate; and (c) a pharmaceutically acceptable excipient. At least one of: (i) the active pharmaceutical ingredient includes at least one covalently bonded amine group that is subject to conversion to nitrosamine; or (ii) the solid oral pharmaceutical composition includes at least one amine, that is other than the amine group covalently bonded to/within the active pharmaceutical ingredient, and which is subject to conversion to nitrosamine. The nitrosamine inhibitor is present in an amount at least sufficient to reduce the amount of nitrosamine formed in the solid oral pharmaceutical composition, compared to the amount of nitrosamine formed in a comparative solid oral pharmaceutical composition that is free of the nitrosamine inhibitor.