Acetaminophen, a drug widely used to reduce pain and fever. It is available over-the-counter under the trade names Tylenol and Panadol and is also an ingredient in stronger prescription painkillers, such as Percocet and Darvocet.
Acetaminophen is a popular alternative to aspirin because it is often just as effective for pain and fever but has fewer objectionable side effects. It does not cause stomach irritation or intestinal bleeding, and individuals who are allergic to aspirin can take acetaminophen safely. Unlike aspirin, acetaminophen does not reduce inflammation such as that associated with rheumatic diseases, nor does it inhibit blood clotting.
While acetaminophen is extremely safe in normal doses, an overdose can cause serious liver injury and even death. If the overdose is diagnosed promptly, administration of N-acetylcysteine will prevent serious liver injury. In addition, evidence indicates that a form of kidney damage known as analgesic nephropathy can result from daily, years-long use of pain medications containing a combination of acetaminophen and aspirin (with aspirin possibly helping to stimulate acetaminophen’s effect on the kidneys).
Aspirin is the drug most widely used as an analgesic, or pain reliever; antipyretic, or fever reducer; and antiinflammatory agent. Its activity is based on chemicals called salicylates, derived from willow and other plants and known for their medicinal properties since ancient times. Modern aspirin—acetylsalicylic acid—was synthesized in the laboratory in the late 19th century and introduced into widespread medical use in 1899. Since then it has become the standard by which all other analgesics and antipyretics are measured.
Aspirin is most effective in relieving slight to moderately severe pain, particularly headache, muscle aches, and joint pains. It is less effective against deep-seated pain originating in internal organs. Because it suppresses inflammatory processes while relieving pain, it is still the treatment of choice for arthritis and related disorders. The major therapeutic effects of aspirin involve the inhibition of the synthesis of prostaglandins, fatty acids with hormonelike functions. Certain prostaglandins form end-products responsible for fever, inflammation, platelet aggregation, controlling blood flow, and protecting the stomach lining. By blocking the production of these prostaglandins, aspirin can reduce fever and prevent platelets from forming blood clots. Aspirin has been proved to decrease further heart attacks in patients who have had one heart attack and in patients with an unstable pattern of angina. It is also recommended for patients with minor strokes and transient ischemic attacks.