CYP2C9 and Hirsutism: Studies in patients have shown that carriers of the variants CYP2C9*2, CYP2C9*3 and CYP2C19*2, CYP2C19*3, CYP2C19*4, show a higher likelihood for adverse effects with phenytoin, such as gum hyperplasia, hirsutism, skin and neurological symptoms, such as confusion, dysarthria, memory loss or deterioration, astasia, and dizziness (Mamiya et al., 1998; Ninomiya et al., 2000; Kidd et al., 2001; Ramasamy et al., 2007; Depondt et al., 2011; Babu et al., 2013; Dorado et al., 2013).