Cognition, oxidative stress and vitamin B12 levels evaluation on patients under long-term omeprazole use

To evaluate the differences concerning cognitive performance, oxidative stress and vitamin B12 levels in omeprazole users under treatment for longer than six months. A case-control study was developed with 44 omeprazole users (OU; 81.8 % female, 66 ± 8.7 years old) and 35 nonusers (NOU; 88.6 % female, 62 ± 8.7 years old). The cognitive ability was assessed through tests approaching attention, memory and executive functions. The vitamin B12 was dosage using a chemiluminescent immunoassay and oxidative stress analysis, based on the evaluation of malondialdehyde, enzymatic activity of extracellular superoxide dismutase, glutathione peroxidase, catalase and the ferric reducing antioxidant power in plasma. A significant increase of the ferric reducing antioxidant power [omeprazole users (OU) group = 1690 µM ± 441 and nonusers (NOU) group = 1308 ± 616; P value=0.002] and a decrease on glutathione peroxidase levels [OU group = 0.534 (0.27-10.63) and NOU group = 71.86 (14.36-173.1); P value=0.006] were found on omeprazole users group, as well as differences on cognitive performance, with impairments on executive functions, automatic and attentional processing. Long-term use of omeprazole is suggested to induce an oxidative stress condition, which causes neurotoxicity and cognitive decline.