CYP2C19 and duodenal ulcer: Current guidelines recommend the use of acid‐suppressive drugs in ventilated patients to prevent stress ulcers and gastric bleeding.14 Therefore, pantoprazole, a proton pump inhibitor, which is also metabolized by CYP2C19 enzymes, is frequently used in critically ill patients.15 However, similarly to clopidogrel, genetic variants in the CYP2C19 enzymes influence the pharmacokinetics (PKs) of pantoprazole.16