APAP is the scientific abbreviation for acetaminophen, commonly known by the brand name Tylenol in the United States. Acetaminophen, sold over the counter, is a safe drug when taken in doses of less than 4,000mg per day for adults. Doses of 7,000mg a day in adults can cause severe toxicity and death. APAP overdose is responsible for more than 56,000 emergency room visits a year and around 460 deaths, according to Oregon State University (OSU). Acetaminophen overdose causes acute liver damage that may require liver transplantation; many overdose symptoms are related to liver dysfunction.
Gastrointestinal Symptoms
Acetaminophen toxicity occurs in stages, with stage 1 occurring within 24 hours of overdose, according to the Merck Manual. Stage I symptoms include nausea, vomiting, diarrhea and loss of appetite. In stage II, 24 to 72 hours after overdose, upper right quadrant pain follows. Gastrointestinal bleeding may occur in later stages from interference with the blood's ability to clot. The liver may be enlarged and tender to the touch.
Liver Symptoms
Acetaminophen overdose is the most common cause of acute liver failure in the United States, OSU reports, causing around 39 percent of all cases. One out of four people with an overdose progressed to liver failure that required liver transplant, and 70 percent were still alive three weeks after overdose. Symptoms of severe liver damage appear 72 to 96 hours after ingestion in stage III of the disease, the Merck Manual states. Liver symptoms include elevated liver enzymes and bilirubin as well as coagulation problems noted in blood tests. Jaundice, a yellow tinge to the whites of the eyes and skin is caused by the accumulation of bilirubin. Confusion, called hepatic encephalopathy, occurs because the liver can't remove toxins from the blood.
Other Effects
Systemic effects of acetaminophen overdose include paleness, sweating, fatigue, lethargy and irritability. Hypoglycemia, low blood sugar, convulsions and coma can follow. Kidneys may fail, and inflammation of the pancreas may occur. Multiple organ failure can lead to death in some cases, according to Merck.
