rs622342A>C in SLC22A1 is associated with metformin pharmacokinetics and glycemic response.

Polymorphisms in SLC22A1 lead to variability in metformin clinical efficacy. Sixty-three Lebanese patients with type 2 diabetes who administered metformin, were followed up for six months and genotyped for rs622342A>C. The area under the plasma concentration-time curve and the maximum concentration of metformin was highest in CC patients (P ≤ 0.03). There was a significant difference between groups in the percentage decrease in fasting blood sugar (FBS) and glycated hemoglobin (HbA1c). Going into the same direction, rs622342C was associated with decrease in FBS levels after three and six months of treatment (P ≤ 0.02), whereas with HbA1c, the decrease was noticed after six months (ß = -2.78; P = 0.03). In contrast, the serum levels of lactate and creatinine did not vary significantly according to rs622342A>C genotypes. The rs622342A>C in SLC22A1 may be associated with metformin pharmacokinetics and variability in therapeutic efficacy.