Tylenol (acetaminophen), is one of the most popular over-the-counter pain reliever in the United States. When taken as directed, your body can eliminate acetaminophen safely and harmlessly. Too much of the drug, however, overwhelms the system. The body then begins to break acetaminophen down into toxic substances that can be fatal. The journal Hepatology states that acetaminophen overdose "far exceeds" other causes of liver failure in the United States, and that 50 percent of acetaminophen overdoses are accidental.
Stage 1
Early symptoms of Tylenol overdose are mild and may not be noticed. They include nausea, vomiting, diarrhea and abdominal pain. Dizziness, confusion and agitation can also occur at high doses. The recommended maximum dose of acetaminophen is 4 grams (the equivalent of eight extra strength tablets) per day. A dose of 14 grams is fatal, and liver damage can occur in doses of 7 grams. In alcoholics, people with anorexia, AIDS, and those taking drugs like phenobarbital or phenytoin, liver toxicity can occur even when the drug is taken as directed.
The drug acetylcysteine is an antidote to acetaminophen overdose. For maximum effect, acetylcysteine needs to be given as soon as possible after an overdose occurs.
Stage 2
After 24 to 36 hours, the initial symptoms of acetaminophen toxicity will decrease, but symptoms of liver injury will appear. Liver damage is diagnosed by blood tests. Dying liver cells release enzymes into the blood stream. Serum creatinine may rise, which is a symptom of kidney failure.
Stage 3
Most cases of acetaminophen toxicity bypass stage 3 and the patient will begin to recover. In some cases, however, liver failure will continue to progress after 36 to 96 hours. This is known as fulminant hepatic failure. The initial symptoms of nausea, vomiting, diarrhea and abdominal pain will return. Jaundice, which appears as a yellowing of the skin or the whites of the eyes, can also occur. The patient will have low blood sugar, and the blood will not clot properly. Patients who deteriorate to this point will likely die of multiple organ failure unless a liver transplant is performed.
Stage 4
People who do not experience full liver failure will progress to stage 4 after four days. In the recovery phase, the liver function will return to normal over a course of one to three weeks.
References
- Hepatology Journal: Acetaminophen-Induced Acute Liver Failure: Results of a United States Multicenter, Prospective Study
- MD Consult: Acetaminophen Poisoning; Dennis Saver, Gordon Baustian, Barbara Blok, and Heikki Nikkanen; 2009
- Basic and Clinical Pharmacology; Bertram Katzung; 2007
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