Review Article

Acetaminophen Overdose in Pregnancy

Authors: Jason M. Wilkes, MD, Larry E. Clark, MD, Jorge L. Herrera, MD


Acetaminophen (APAP) is the most common drug overdose in pregnancy. Available data regarding APAP overdose in pregnancy is limited to case reports and a small prospective case series. APAP has been demonstrated to cross the placenta and in toxic doses may harm the fetal and maternal hepatocytes. Fetal hepatocytes metabolize APAP into both active and toxic metabolites. These toxic metabolites may cause fetal hepatic necrosis. N-acetylcysteine (NAC) has also been demonstrated to cross the placenta and may bind toxic metabolites in both the mother and the fetus. Limited data suggest that the majority of morbidity and mortality from APAP overdose can be averted by initiation of NAC within the first 16 hours of ingestion and possibly even later. NAC may be safely administered during pregnancy and should be initiated early after APAP overdosage. The literature was reviewed through the use of OvidMEDLlNE® database, encompassing 1966 to the present. Searches were conducted using the key words acetaminophen, paracetamol, N-acetylcysteine, overdose, and hepatotoxicity. The search was further refined by selecting articles that contained these search words together with the key word pregnancy. Only English language papers were reviewed. Articles were selected on the basis of relevance to the topic. Pertinent citations found in the selected articles were also reviewed.

Key Points

* Data on acetaminophen overdose and pregnancy are limited.

* Acetaminophen has been demonstrated to cross the placenta and cause toxic metabolites in both the mother and the fetus.

N-acetylcysteine should be initiated early after acetaminophen overdosage in pregnancy to prevent harm to both the mother and the fetus.

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