Proton-pump inhibitors and chronic kidney disease: Hidden consequences of an inappropriate drug use?

Proton-pump inhibitors (PPIs) are the most effective therapy for gastric acid- related diseases. They are generally well tolerated with rare, often self-limiting adverse reactions. On the other hand, there is growing concern regarding the increased public access and inappropriate PPI use. This review aims to give a critical appraisal of current literature and to analyze a possible relationship between renal disorders and PPI use. A plethora of observational pharmacoepidemiological studies link PPI therapy to the development of acute interstitial nephritis (AIN). Most of these studies show a higher risk for acute kidney injury, de novo chronic kidney disease, and end-stage renal disease. However, current evidence is inadequate to establish a causal relationship between PPI use and many of the proposed renal syndromes. Residual confounding and bias related to study design and the over extrapolation of quantitatively small treatment effects contributed to the unnecessary controversy about PPI safety. Undoubtedly, PPI use may rarely induce AIN. Given the worldwide use of PPIs, the number of patients with biopsy- proven AIN is extremely small. However, more research is required to explore the underlying pathophysiological mechanisms and possible differences between commercially available PPIs regarding adverse renal effects. Till then, the PPIs should be used in the lowest effective dose, and inappropriate use should be avoided.