In all cases of suspected overdose, immediately call your regional poison control center, and/or contact a physician immediately.
Signs and Symptoms: Following an acute overdose, toxicity may result from acetaminophen or phenyltoloxamine citrate. In acetaminophen overdosage: dose dependent, potentially fatal hepatic necrosis effect is the most serious adverse effect. Renal tubular necrosis, hypoglycemic coma, and thrombocytopenia may also occur.
Early symptoms following a potentially hepatotoxic overdose may include nausea, vomiting, diaphoresis, and general malaise. Clinical and laboratory evidence of hepatotoxicity may not be apparent until 48 to 72 hours postingestion. In adults, hepatotoxicity has rarely been reported with acute overdoses of less than 10 grams or fatalities with less than 15 grams.
Recommended Treatment: A single or multiple overdose with acetaminophen or phenyltoloxamine citrate is a potentially lethal overdose, and consultation with a regional poison control center is recommended. Immediate treatment includes support of cardio respiratory function and measures to reduce drug absorption. Vomiting should be induced mechanically if the patient is alert (adequate pharyngeal and laryngeal reflexes). If the dose of acetaminophen may have exceeded 140 mg/kg, acetylcysteine should be administered as early as possible. Serum acetaminophen levels should be obtained since levels four or more hours following ingestion help predict acetaminophen toxicity. Do not await acetaminophen assay results before initiating treatment. Hepatic enzymes should be obtained initially, and repeated at 24-hour intervals. Methemoglobinemia over 30% should be treated with methylene blue by slow intravenous administration.