Baby Got NAC

A 21-year-old woman with no past medical history presented to the emergency department for evaluation of an overdose. She was brought in by ambulance after her boyfriend called the police because she admitted to him that she had ingested a large amount of acetaminophen (APAP). The patient was 21 weeks pregnant and admitted to having ingested half of a bottle of extra-strength Tylenol six hours before arrival. The ED contacted the poison control center, and asked if N-acetylcysteine (NAC) is safe in pregnancy and if the dosing regimen changes for the pregnant patient.NAC's Mechanism of ActionAPAP is primarily metabolized by conjugation via glutathione. When glutathione channels are depleted, APAP is then metabolized via the CYP P450 system to its toxic metabolite N-acetyl-P-benzoquinoneimine (NAPQI), which is what causes hepatotoxicity. NAC acts as a precursor for the synthesis of glutathione, replenishing glutathione channels and steering metabolism away from the CYP 450 system and away from the production of NAPQI. Minor mechanisms of NAC also include acting as a substrate for sulfation, another minor mechanism of metabolism, and NAC also binds directly to NAPQI reducing it and making it no longer hepatotoxic.Pregnant Women and APAP ToxicityMaternal absorption and metabolism of APAP are not affected by pregnancy. Both (APAP) and n-acetylcysteine (NAC) traverse the placenta. The conjugates of APAP do not cross, therefore NAPQI does not cross the placenta. The predominant meta...
Source: The Tox Cave - Category: Emergency Medicine Tags: Blog Posts Source Type: blogs