Acetaminophen is widely used to reduce pain and fever.

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Milk Thistle , Coenzyme Q 10 (CoQ 10 ) , Methionine  

Possible Helpful Interactions

The herb milk thistle and the supplements coenzyme Q 10 (CoQ 10 ) and methionine might help protect the liver against damage caused by excessive use of acetaminophen. 1–3 However, it is extremely dangerous to take excessive amounts of acetaminophen, and we certainly wouldn't count on any of these supplements to protect you from harm if you do so!

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Vitamin C  

Possible Increased Risk of Toxicity

One study from the 1970s suggests that very high doses of vitamin C (3 g daily) might increase the levels of acetaminophen in the body. 4 This could potentially put you at higher risk for acetaminophen toxicity. You probably don't need to be overly concerned if you take acetaminophen in recommended doses now and then for pain or fever. However, a problem might occur if you take higher-than-recommended doses or if you take high doses of acetaminophen on a regular basis, such as for osteoarthritis. The risk increases if you have liver or kidney impairment or if you drink alcoholic beverages regularly, which taxes the liver even more.

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Chaparral, Comfrey, and Coltsfoot  

Possible Harmful Interaction

The herbs chaparral ( Larrea tridentata or L. mexicana ), comfrey (Symphytum officinale), and coltsfoot (Tussilago farfara) contain liver-toxic substances. Combined use with acetaminophen could accentuate the liver toxicity of the medication.

Citrate  

Possible Harmful Interaction

Potassium citrate, sodium citrate, and potassium-magnesium citrate are sometimes used to prevent kidney stones . These supplements reduce urinary acidity, and can therefore lead to decreased blood levels and effectiveness of acetaminophen. 5