Acetaminophen poisoning is a toxic reaction resulting from the ingestion of excessive doses of the drug. In adults, dosages exceeding 10-15 grams can produce liver failure and dosages exceeding 25 grams can be fatal. Symptoms such as nausea and vomiting, profuse sweating, pallor, and oliguria (scanty amounts of urine) are associated with the onset of acetaminophen poisoning. Jaundice and pain in the upper abdomen, hypoglycemia, encephalopathy, abnormal functioning of brain tissue, and kidney failure may become apparent as drug toxicity increases.
When a person takes acetaminophen, it is metabolized by a number of metabolic systems in the liver, including one called the P450 system. This results in an intermediate by-product, or metabolite, that is very reactive and can kill liver cells. This intermediate metabolite is normally converted to a harmless final metabolite by an antioxidant in the liver called glutathione (Uhlig et al. 1990; Deleve et al. 1991; Richie et al. 1992). A large dose of acetaminophen reduces the glutathione supply, resulting in progressive necrosis of the liver, sometimes evidenced in as little as 5 days. Alcoholics and those on certain medications that stimulate the P450 system are at particular risk because, with increased P450 activity, more toxic intermediate is created than there is glutathione available to further metabolize it to something harmless. Although not fatal, chronic acetaminophen use decreases the functional capacity of the liver.
Acetaminophen can also cause permanent kidney damage when taken over extended periods of time. This damage can be lethal to those with underlying kidney disease. The Food and Drug Administration does not require the manufacturers of Tylenol and other brands of acetaminophen to adequately warn people with kidney disease to avoid this pain medication. However, for those in chronic pain who cannot find relief from natural pain relief therapies (see Pain and Arthritis protocols), it is suggested that Tylenol and other brands of acetaminophen be used sparingly.
500mg per pill so 2 pills = 1 gram of acetaminophen