CYP2D6 and Bradycardia: Also, the study by Yuan et al. [65] reported that the CYP2D6 SNPs rs16947 (2850C > T, R296C) and rs1135840 (4180C > G, S486T) did not influence the IOP lowering effect induced by timolol (P = 0.339 and P = 0.903, respectively), while rs16947 CT (P = 0.043) and TT (P = 0.043) displayed a predisposition to bradycardia than rs16947 CC, although without significant difference between CT and TT (P = 0.177).