Initial management

Absorption of acetaminophen from the stomach is not complete for at least 4 h after ingestion, and may take much longer with slow-release preparations. Therefore plasma levels before this time are misleading, and attempts should be made to limit further absorption of the drug with either activated charcoal or syrup of ipecacuanha. Special care should be taken with protection of the airway, particularly in mixed overdoses where sedation and central nervous system depression can be an early feature. Further management is based around a plasma acetaminophen level related to the time of ingestion, and a serum creatinine and prothrombin time if the patient presents more than 24 h after ingestion, the overdose is greater than 12 g of acetaminophen, or the patient is in one of the high-risk groups. An abnormality in either the creatinine or the prothrombin time can be an early indication of severe hepatic damage and the only sign of a serious overdose in high-risk patients. Any patient with a plasma acetaminophen level after 4 h which is greater than the standard treatment line, or greater than half the standard line in a high-risk patient should be treated with the antidote ^-acetylcysteine (NAC). NAC should also be administered if the timing is suspect or inaccurate.

NAC acts by a number of mechanisms to prevent hepatotoxicity. The main action is to increase hepatic glutathione production by acting as a source of cysteine, which replenishes intracellular glutathione and allows an increase in conjugation of NAPQI. It can also act as both a sulfur donor and a direct substitute for glutathione, which causes an increase in both sulfation of acetaminophen to its non-toxic metabolite and conversion of NAPQI back to acetaminophen. NAC is most effective when given within 8 h of the overdose; however, it remains a safe and effective treatment even after 15 h. NAC is administered as an intravenous infusion, starting with a loading dose of 150 mg/kg over 15 min followed by 50 mg/kg for 4 h and then 100 mg/kg for 16 h. Following the initial NAC regimen, the presence of coagulopathy, renal dysfunction, or symptoms and signs attributable to the acetaminophen overdose should be treated with further infusions of NAC at 150 mg/kg every 24 h and daily monitoring of the international normalized ratio (INR) and plasma creatinine concentration. Allergic reactions to NAC are rare and are usually only seen with the initial loading dose. In cases where true anaphylaxis has occurred, oral NAC or methionine are available as substitutes.

Kicking Fear And Anxiety To The Curb

Kicking Fear And Anxiety To The Curb

Kicking Fear And Anxiety To The Curb Can Have Amazing Benefits For Your Life And Success. Learn About Calming Down And Gain Power By Learning Ways To Become Peaceful And Create Amazing Results.

Get My Free Ebook

Post a comment