Treatment of acetaminophen overdose.


Zed PJ, Krenzelok EP




Am J Health Syst Pharm


The therapeutic management of patients with acetaminophen overdose is reviewed. Acetaminophen overdose results in more calls to poison control centers in the United States than overdose with any other pharmacologic substance. Although the optimal management strategy remains controversial, the literature suggests a general approach that can be followed until there is evidence supporting a different strategy. A single dose of activated charcoal should be administered within one hour of acetaminophen overdose. Other means of gastric decontamination are not warranted. Acetylcysteine should be given if the acetaminophen concentration exceeds the treatment line in the Rumack-Matthew nomogram. If a patient is treated within 10 hours of acetaminophen ingestion, the risk of hepatoxicity is low. In patients 10-24 hours after ingestion, a 72-hour oral or 48-hour i.v. acetylcysteine regimen should be used. Among patients with fulminant hepatic failure, acetylcysteine should be given until recovery or death occurs. In patients who have taken extended-release acetaminophen, the acetaminophen concentration should be measured at four hours and, if this level exceeds the treatment line, acetylcysteine should be started immediately. If the concentration is below the treatment line, a second acetaminophen concentration should be determined four to six hours later. If this level is above the treatment line, acetylcysteine therapy should be started. Cimetidine appears to have no role in the management of acetaminophen overdose. Children should be diagnosed and treated the same way as adults, and pregnant patients should be managed no differently than nonpregnant patients. An evaluation of the literature on acetaminophen poisoning verifies the usefulness of acetylcysteine as a hepatoprotective agent. A single dose of activated charcoal may also be useful if given within one hour of acetaminophen ingestion.