The use of dipyrone in the ICU is associated with acute kidney injury: A retrospective cohort analysis

Background: Use of dipyrone (metamizole) in perioperative and ICU pain therapy remains controversial due to a lack of solid evidence weighing dipyrone benefit against its potential life-threatening complications. Although dipyrone has known analgesic and antipyretic properties, its mechanisms of actions are incompletely understood. Although dipyrone effects on renal vasodilator prostaglandin synthesis are documented, little is known about its potential renal side effects, especially in the critical care environment.

Objective: Investigation of the perioperative nephrotoxic potential of dipyrone in patients prone to acute kidney injury (AKI).

Design: Retrospective cohort study.

Setting: Single centre study in a tertiary referral hospital from January 2013 until June 2013.

Patients: A total of 500 consecutive patients aged 18 years and older referred to the anaesthesia ICU. Patients were excluded if admitted from or discharged to other ICUs, if referred for post resuscitation care, or if repeatedly admitted to the ICU.

Main outcome measures: Incidence of AKI, as defined by the Kidney Disease: Improving Global Outcomes Acute Kidney Injury Work Group criteria, and duration of vasopressor therapy.

Results: Use of dipyrone was associated with an increased incidence of AKI in a dose-dependent manner with a 1.6-fold increase in the incidence of AKI with each additional gram of intravenous dipyrone per day. Dipyrone dose of more than 2.5 g day was the best risk predictive cut-off for AKI. Patients receiving dipyrone on the ICU presented with a prolonged duration of vasopressor therapy.

Conclusion: Increasing dipyrone dosage is a potential independent risk factor for AKI in adult ICU patients and may prolong vasopressor therapy. Clinical evidence for a benefit of dipyrone therapy in the ICU is insufficient and needs further critical evaluation.