NAC therapy should be started once deemed appropriate by history, Rumack-Matthew nomogram, and acetaminophen and transaminase levels. Intravenous NAC is less effective than the oral regimen in reducing hepatotoxicity if administered more than 10 hours after ingestion and may not be beneficial after 16 hours. Oral therapy is less efficacious after 10 hours because of the emetogenic properties of NAC and the GI effects of the overdose. Adverse effects include erythema at injection site, diffuse urticaria, bronchospasm, fever, and anaphylaxis. All reactions seem to be histamine mediated and abate after discontinuation of infusion and administration of antihistamines.
Informed consent is required.
One study comparing IV NAC with oral NAC found that IV NAC therapy was as effective as oral therapy when administered within 10 hours of ingestion of the toxic substance. Also, IV NAC is preferable therapy for patients in whom oral therapy may be delayed because of emesis or drug effects. Clinicians should maintain a high index of suspicion and intervene promptly to lower the morbidity and mortality associated with acetaminophen poisoning. Emergency intervention includes a good history and physical examination, basic life support, gastric lavage, charcoal admnistration, and NAC when indicated. Litovitz T, Klein-Schwartz W, Dyer KS, et al.