Synonyms: | 1,6,7,8,9,10-Hexahydro-6,10-methano-2H-pyrazino[2,3-h][3]benzazepin-2-one;1,6,7,8,9,10-Hexahydro-2H-6,10-methanoazepino[4,5-g]quinoxalin-2-one;6,10-Methano-2H-pyrazino[2,3-h][3]benzazepin-2-one, 1,6,7,8,9,10-hexahydro-;Varenicline Hydroxy Impurity;Hydroxy Varenicline |