Importantly, despite a proven nephroprotective role of antagonists of the renin-angiotensin-aldosterone system (RAAS), these drugs may cause harm instead of good when used in patients with dehydration, hypotension, hyperkalemia, progressing AKI, and advanced CKD, as well as in combination with non-steroidal anti-inflammatory drugs (NSAIDs). Here, REN is linked to acute kidney injury.