Safety Profile of Omeprazole: A Narrative Review Of Adverse Drug Reactions and Risk Factors

Omeprazole, a widely prescribed proton pump inhibitor (PPI), is a cornerstone therapy for acid?related gastrointestinal disorders, including gastroesophageal reflux disease, peptic ulcer disease, and Zollinger–Ellison syndrome. While generally safe and effective, prolonged or inappropriate use has been linked to a spectrum of adverse drug reactions (ADRs). Common ADRs include headache, abdominal discomfort, nausea, diarrhea, and flatulence, which are usually mild and self?limiting. However, serious complications—such as Clostridioides difficile infection, interstitial nephritis, hypomagnesemia, vitamin B12 deficiency, bone fractures, hepatotoxicity, and severe cutaneous reactions—though rare, pose significant clinical challenges. Risk factors influencing ADR incidence include treatment duration, high dosage, advanced age, polypharmacy, comorbid conditions, and genetic polymorphisms in CYP2C19 metabolism, which alter drug bioavailability and efficacy. Clinical pharmacists play a crucial role in mitigating these risks through therapeutic optimization, monitoring of laboratory parameters, early identification of drug interactions, and patient education. Evidence?based deprescribing strategies and routine safety surveillance are essential to minimize preventable harm while preserving therapeutic benefit. This review highlights the clinical significance of omeprazole?associated ADRs from a pharmacist’s perspective, emphasizing the importance of rational prescribing, vigilant monitoring, and interdisciplinary collaboration in ensuring patient safety.