Metamizole for Postoperative Pain Therapy in Infants Younger than 1 Year.
BackgroundDue to possible serious adverse drug reactions (ADRs), the use of metamizole for postoperative pain therapy in infants is a subject of debate. Safety studies with large sample sizes are missing.AimThis prospective multicenter observational study was conducted to evaluate the use of metamizole in infants younger than 1 year undergoing surgery with a particular focus on possible serious ADRs (e.g., hemodynamic, anaphylactic or respiratory reactions, and agranulocytosis).MethodsInfants aged up to 1 year (American Society of Anesthesiologists [ASA] I-III) receiving a single dose of metamizole for postoperative pain therapy were enrolled. Patient demographics, main and secondary diagnosis, surgical procedures performed, metamizole dose, hemodynamic data, use of other analgesics and regional blocks, results of pain measurement, and incidence of ADRs were documented using a standardized case report form.ResultsA total of 316 infants observed at five pediatric centers were included for analysis (age 4.4 ± 3.7 [0.06-12] months). Mean metamizole dose was 17.8 ± 3.1 (9.2-29.8) mg·kg-1. Mean arterial pressure (MAP) remained stable during metamizole infusion (MAP before infusion 45 ± 9.5 [25-95] and after infusion 45 ± 9.2 [25-99] mm Hg). Erythema was observed in one patient (ADRs total: 0.3%, 95% confidence interval: 0.27-0.32). No respiratory adverse events directly related to the metamizole administration and no clinical signs of agranulocytosis were reported.ConclusionSingle intravenous doses of metamizole used for prevention or treatment of postoperative pain were safe in more than 300 infants younger than 1 year. The statistical probability of serious ADRs (e.g., hemodynamic, anaphylactic or respiratory reactions) was lower than 1%. The sample size and follow-up were not sufficient to detect agranulocytosis.
Clinic for Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, Germany.
Robert
R
Sümpelmann
Clinic for Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, Germany.
Melanie
M
Fieler
Department of Anesthesia, Pediatric Intensive Care and Emergency Medicine, Auf der Bult Children's Hospital, Hannover, Germany.
Christoph
C
Eich
Department of Anesthesiology and Intensive Care Medicine, Cnopf'sche Kinderklinik/Klinik Hallerwiese, Nuremberg, Germany.
Karin
K
Becke
Department of Anesthesiology and Pediatric Anesthesiology, Krankenhaus Barmherzige Brüder Regensburg/Klinik St. Hedwig, Regensburg, Germany.
Gregor
G
Badelt
Department of Anesthesiology, Intensive Care, Emergency Medicine, Transfusion Medicine and Pain Therapy, Protestant Hospital Bielefeld, Bielefeld, Germany.
Klaus
K
Leimkühler
Clinic for Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, Germany.
Nils
N
Dennhardt
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects* / Q000627:therapeutic use; D004177:Dipyrone / Q000009:adverse effects* / Q000627:therapeutic use; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007275:Injections, Intravenous; D008297:Male; D010149:Postoperative Pain / Q000188:drug therapy* / Q000517:prevention & control; D011446:Prospective Studies; D016896:Treatment Outcome
D000894:Anti-Inflammatory Agents, Non-Steroidal; D004177:Dipyrone