Intentional Naproxen Overdose Causing Metabolic Acidosis: A Case Report

Naproxen is a widely available, over-the-counter medication often perceived as safe when used appropriately. However, in cases of overdose, especially when co-ingested with other substances, it may contribute to significant metabolic disturbances that are not commonly seen in nonsteroidal anti-inflammatory drug (NSAID) use. We describe the case of a 24-year-old female who presented to the Emergency Department after an intentional multidrug overdose involving naproxen, hydroxyzine, and clonazepam. On arrival, she was found to have an elevated anion gap metabolic acidosis. Common causes of metabolic acidosis were ruled out, and her condition improved with supportive care, including intravenous fluids and a bicarbonate infusion. Clinical findings suggested that naproxen played a significant role in the development of the acid-base imbalance. This case report aims to illustrate that large doses of naproxen may contribute to metabolic acidosis in overdose situations. In cases of intentional ingestions involving multiple substances, clinicians should consider NSAIDs as potential contributors to acid-base abnormalities, particularly when more common causes are excluded.