SLC22A1 is a gene that encodes a protein known as the organic cation transporter 1 (OCT1). This protein is primarily found in the liver and plays a crucial role in the transport of various organic cations, including drugs and metabolites, across cell membranes. By facilitating the uptake of these substances, OCT1 helps regulate their levels in the body and influences drug metabolism. Mutations or variations in the SLC22A1 gene can affect the function of OCT1, leading to differences in how individuals respond to certain medications. This variability can impact drug efficacy and safety, making SLC22A1 an important factor in personalized medicine and pharmacogenomics.