Abstract: PO1099
An Extremely Rare Interaction Between Two Commonly Used Drugs
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Basic
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid, Electrolyte, and Acid-Base Disorders
- 901 Fluid, Electrolyte, and Acid-Base Disorders: Basic
Authors
- Furtado, Maria Teresa, Hospital de Sao Bernardo, Setubal, Setubal, Portugal
- Gonçalves, Catarina Abrantes, Hospital de Sao Bernardo, Setubal, Setubal, Portugal
- Valerio, Patrícia, Hospital de Sao Bernardo, Setubal, Setubal, Portugal
Introduction
The use of Paracetamol and Flucloxacillin can result in an elevated anion gap metabolic acidosis. Interaction between these drugs is a rare disorder that results from accumulation of pyroglutamic acid. Affected patients are usually women with chronic illness, sepsis, and malnutrition.
Case Description
We present the case of a 79 year-old hypertensive and diabetic woman with a past medical history of chronic kidney disease (baseline creatine of 1.6 mg/dl). She was admitted to the hospital due to a Methicillin-Sensitive Staphylococcus Aureus spondylodiscitis and she underwent surgical decompression with postoperative severe pain complaints. In that context, she was started on opioids, NSAIs and high-dose paracetamol (4 g daily), and Flucloxacillin (12 g daily). After 10 days she presented with dyspnea and generalized weakness. Blood gas analysis revealed metabolic acidosis (pH 7.35; pCO2 16 mmHg; pO2 102 mmHg; HCO3 8 mmol/L; anion gap 22 mmol/L; lactate 0.4 mmol/L). Laboratory tests showed hypoalbuminemia of 1g/dl in the context of severe malnutrition, and no worsening of kidney function. The patient was screened for lactic acidosis, ketoacidosis, toxic alcohol ingestion and salicylate poisoning with no positive findings. Finally, we concluded accumulation of pyroglutamic acid secondary to concomitant use of flucloxacillin and paracetamol in high doses as the leading cause of elevated anion gap metabolic acidosis. Despite these drugs were immediately stopped and sodium bicarbonate was started, the patient showed no clinical improvement and presented with respiratory exhaustion. Hemodialysis was started to correct the acid-base disorder.
Discussion
Despite being extremely rare, metabolic acidosis induced by drug interaction between Paracetamol and Flucloxacillin is a severe and potentially life-threatening disorder. We recognize the relevance of this case since these drugs are commonly prescribed together.