Drug Mechanism of Action Transporter gene/protein Response affecting Polymorphism
Sulfonylureas Increase β‑cell insulin secretion by a glucose-independent mechanism Not studied CYP2C9 *2/*2, *2/*3, *3/*3, TCF7L2, E23K variant of KCNJ11
Meglitinides Increase β‑cell insulin secretion by a glucose-independent mechanism SLCO1B1 CYPC8*1/*3, CYP2C9*3
DPP4 inhibitors Increase insulin secretion by a glucose-dependent mechanism Suppress glucagon secretion by a glucose-dependent mechanism Incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) TCF7L2, MTNR1B
GLP1 receptor agonists Increase insulin secretion by a glucose-dependent mechanism Suppress glucagon secretion by a glucose-dependent mechanism GLP receptor T149M polymorphism
Thiazolidinediones Decrease insulin resistance SLCO1B1 (OATP1B1) CYP2C8*3 and *4, PPARG Ala12
Metformin Decrease insulin resistance SLC22A1 (OCT1) SLC22A2 (OCT2) SNP rs622342 in SLC22A1 gene encoding OCT1
α-Glucosidase inhibitors Act within the gastrointestinal tract to lower postprandial glucose excursions   Pro12Ala of PPARG, Gly482 of PGC1A, TT genotype of APM1 polymorphism +276 G/T
Table 3: Polymorphisms affecting drug response.