Pharmacokinetics of NSAIDs and Acetaminophen

Aspirin is absorbed readily from the stomach and small intestine. Approximately 80 to 90 percent of aspirin remains bound to plasma proteins such as albumin. The remaining 10 to 20 percent is widely distributed throughout the body. The unbound or free drug exerts 

FIGURE 15-3 Acetaminophen metabolism. In the liver, acetaminophen is metabolized to a toxic intermediate N-acetyl-p-benzoquinoneimine (NAPQI). NAPQI is quickly detoxified by conjugation with glutathione (GSH), forming mercapturic acid, which is eliminated via the urine. High doses of acetaminophen or liver dysfunction can result in accumulation of NAPQI and subsequent toxicity to liver proteins. 

SECTION 4 Drugs Used to Treat Pain and Inflammation 

---