Metamizol Administration in Perioperative Setting

Dosage and Administration

The American College of Physicians recommends administering metamizol at 2.5 mg/kg/hour after a loading dose of 10-15 mg/kg IV in the perioperative setting, with strict limitation to short-term hospital use (maximum 2-5 days) due to the risk of agranulocitosis 1
A loading dose of 10-15 mg/kg IV is fundamental to rapidly achieve therapeutic levels, and this dose is typically administered intraoperatively or in the immediate postoperative period 1, 2
The infusion rate of 2.5 mg/kg/hour maintains stable analgesic levels without peaks or troughs 1, 2, 3

In patients with moderate to severe renal insufficiency (eGFR <30 mL/min/1.73 m²), the dose should be reduced by 25-50% and closely monitored 1
Metamizol is contraindicated in patients with severe renal insufficiency or end-stage renal disease, and alternative analgesics such as fentanyl or methadone should be prioritized 1

In elderly patients, paracetamol should be prioritized as first-line therapy, and metamizol should be reserved for when paracetamol is ineffective 1
In pediatric patients, the same dosages as adults can be used, with a loading dose of 10-15 mg/kg IV followed by an infusion rate of 2.5 mg/kg/hour 1

A recommended scheme for optimizing pain control includes paracetamol as the base analgesic, metamizol as an adjuvant, and opioids as rescue medication only for breakthrough pain 1, 2
The combination of metamizol with paracetamol and/or NSAIDs significantly reduces the need for opioid rescue 1, 2

Metamizol is contraindicated in patients with a history of metamizol-induced agranulocytosis, and its use should be strictly limited to short-term hospital settings (maximum 2-5 days) due to the risk of agranulocitosis 1, 3, 2
The American Society of Anesthesiologists recommends careful consideration of the risks and benefits of metamizol use in patients with renal insufficiency or other comorbidities 4, 5