Renal Tubular Acidosis Leading to Severe Hypokalemia: An Uncommon Adverse Effect of Nonsteroidal Anti-inflammatory Drugs.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used over-the-counter pain-relieving medications. They are not free from side effects, including effects on the kidneys. We present the case of an elderly woman who presented with severe fatigue and generalized weakness. Her medical history was significant for osteoarthritis, for which her pain was controlled with ibuprofen and naproxen. She was found to have renal tubular acidosis (RTA), causing severe, persistent hypokalemia. The underlying etiology was concluded to be secondary to NSAID use, making this case unique. She gradually improved with electrolyte replacement and discontinuation of NSAIDs. This case emphasizes the importance of considering RTA in the differential diagnosis in the setting of unexplained hypokalemia and metabolic acidosis, especially in the absence of gastrointestinal losses or diuretic use. Discontinuation of NSAIDs with correction of electrolytes is crucial for recovery.