ميتاميزول صوديوم

Metamizole or dipyrone is an analgesic and antipyretic drug derived from pyrazolone. Oral, rectal, intramuscular or intravenous administration every 6 to 8 hours.

Despite its ‘Limited compatibility’, single doses of Metamizole do not require discontinuation of breastfeeding. Do not abuse its use

It is excreted in breastmilk at moderate concentration ^{(Zylber 1986, Rizzoni 1984)}. It has been detected in plasma or in the urine of infants whose mothers were taking it ^{(Rizzoni 1984)}. No side effects have been observed in infants of mothers taking it except for a cyanotic crisis. ^{(Rizzoni 1984)}

An increased risk of acute lymphocytic leukemia has been found in children whose mothers took metamizole during pregnancy and breastfeeding, while the use of paracetamol during pregnancy was a protective factor. ^{(Couto 2015)}

Authorized and widely used in childbirth, puerperium and pediatric analgesia in several countries in Europe and America ^{(Witschi 2019, Bordini 2016, Chaves 2009, Sabo 2001, DUP 1992)}; this is not the case in the US and UK since the 1970s due to risk of skin rashes, anaphylaxis and agranulocytosis (<2 per million), which is actually lower than other medicines. ^{(Bordini 2016)} 

Serious complications reported in Germany, Spain, Poland, Switzerland and Latin America have been very rare (none in relation to breastfeeding), but significant variations in the risk of agranulocytosis have been observed: from 1 per 1,400 treatments in Sweden to 1 in half a million in Greece, suggesting that the risk could be linked to ethnicity with a specific HLA allele, being maximum among descendants of Celtic-British populations. ^{(Shah 2019, Mérida 2009)}

The risk is lower in the pediatric age group and its analgesic effect is not greater than that of intravenous paracetamol. ^{(Ziesenitz 2018, from Leeuw 2017)}.

The European Medicines Agency has standardized information on metamizole for European countries, limiting its dose and use, both in adults and in infants and children and not recommending it during pregnancy and lactation ^{(EMA 2019 and 2018)}. In case of a single administration of metamizole, breastmilk should be discarded for a 48-hour period before resuming breastfeeding. ^{(EMA 2019)}

Other expert consensus considers metamizole safe during breastfeeding. ^{(Dinavitser 2020)}

American Academy of Pediatrics: this medication is usually compatible with breastfeeding. ^{(AAP 2001)}

Until there is more published data on this drug in relation to breastfeeding, occasional and limited use is recommended, and safer known alternatives are preferable ^{(Bar-Oz 2003)}, especially during the neonatal period and in cases of prematurity.