Acetaminophen can be given alone or used in combination with codeine (Tylenol 1, 2, 3) and hydrocodone (Lortab) for patients with more severe pain.

Acetaminophen is used most commonly to treat:

• Fever (> 100.4 F)

  Pain

• It is the only anti-pyretic that can be given to infants safely under 6 months of age.

• It is especially useful with aspirin intolerance (children at risk for Reye syndrome and patients with a history of peptic ulcers)

Mechanisms of Action

• Reversibly inhibits COX-1 and COX-2 (via a different site than NSAID's) and therefore inhibits synthesis of prostaglandins in the CNS.
• Produces antipyresis from inhibition of hypothalamic heat-regulating center.
• Peripherally, it is mostly inactivated and has minimal anti-inflammatory properties.

Side Effects While rare, can include:

Rash Leukopenia Neutropenia Pancytopenia Hepatic necrosis in overdose Elevated ALT and AST Renal injury with chronic use Overdose of acetaminophen causes an accumulation of N-acetyl-p-benzoquinone and can result in hepatotoxicity. For adults this is approximately 150 mg/kg. Therefore, an adult weighing 70 kg would need to ingest 10.5 g or twenty-one 500mg acetaminophen tablets. Treatment is N-acetylcysteine.