Patients should consult their physician before taking any additional prescriptions, over–the–counter medications, nutritional supplements or herbal medications. Many over–the–counter drugs contain acetaminophen. Patients should be careful to read the labels of other drugs, as the presence of acetaminophen in these medications may affect their ability to take acetaminophen as a painkiller.

Patients should not combine the use of acetaminophen with nonsteroidal anti–inflammatory drugs (NSAIDs) such as aspirin or ibuprofen. Consumption of alcohol – even in moderate amounts – while using acetaminophen can substantially increase the risk of liver damage, particularly when drinking is done on an empty stomach. Alcohol use activates a process that turns acetaminophen into chemicals that cause liver damage.

Other drugs of particular concern to individuals taking acetaminophen are:

• Antacids. These may delay or decrease the absorption of acetaminophen.
  
  
• Anticoagulants and thrombolytics (drugs that break up blood clots). Acetaminophen may increase the effects of these drugs.
  
  
• Anticonvulsants. The combination of acetaminophen with these drugs may raise the risk of toxic damage to the liver (hepatotoxicity). In particular, the combination of acetaminophen and the newer anticonvulsant lamotrigine may decrease serum lamotrigine levels.
  
  
• Phenothiazine. Large doses of acetaminophen combined with this drug used to treat psychiatric disorders may raise the risk of hypothermia (abnormally low body temperature).
  
  
• Other drugs and supplements, including:
  
  
• • Sulfinpyrazone. A drug used to treat gout that promotes urinary excretion of uric acid. The combination of sulfinpyrazone and acetaminophen can damage the liver.
    
    
  • Watercress. An herb that may inhibit the oxidative metabolism of acetaminophen. Oxidative metabolism is a chemical process in which oxygen is used to make energy from carbohydrates.
    
    
  • Caffeine. May increase the effects of acetaminophen.