Butalbital

In 205 healthy postmenopausal women, caffeine consumption (three cups of coffee per day) was associated with bone loss in women with calcium intake of less than 800 mg per day. In a group of 980 postmenopausal women, lifetime caffeine intake equal to two cups of coffee per day was associated with decreased bone density in those who did not drink at least one glass of milk daily during most of their life. However, in 138 healthy postmenopausal women, long-term dietary caffeine (coffee) intake was not associated with bone density. Until more is known, postmenopausal women should limit caffeine consumption and consume a total of approximately 1,500 mg of calcium per day (from diet and supplements).

Silymarin is a collection of complex flavonoids found in milk thistle (Silybum marianum) that has been shown to elevate liver glutathione levels in rats. Acetaminophen can cause liver damage, which is believed to involve glutathione depletion. In one study involving rats, silymarin protected against acetaminophen-induced glutathione depletion. While studies to confirm this action in humans have not been conducted, some doctors recommend silymarin supplementation with 200 mg milk thistle extract, containing 70–80% silymarin, three times per day for people taking acetaminophen in large amounts for more than one year and/or with other risk factors for liver problems.

One small study found that hibiscus could decrease levels of acetaminophen if the drug was taken after the tea was consumed though it was not entirely clear if the decreases were clinically significant.

Hospitals use oral and intravenous NAC to treat liver damage induced by acetaminophen overdose poisoning. NAC is often administered intravenously by emergency room doctors. Oral NAC appears to be effective for acetaminophen toxicity.

An uncontrolled trial compared intravenous NAC with oral NAC in children with acetaminophen poisoning and found that both methods were equally effective in reversing acetaminophen-induced liver toxicity. However, acetaminophen toxicity is a potential medical emergency, and should only be managed by qualified healthcare professionals.

Guaraná (Paullinia cupana) is a plant with a high caffeine content. Combining caffeine drug products and guaraná increases caffeine-induced side effects.

Gomisin A is a constituent found in the Chinese herb schisandra (Schisandra chinensis). In a study of rats given liver-damaging amounts of acetaminophen, gomisin A appeared to protect against some liver damage but did not prevent glutathione depletion (unlike milk thistle, as reported above). Studies have not yet confirmed this action in humans.

Taking 3 grams vitamin C with acetaminophen has been shown to prolong the amount of time acetaminophen stays in the body. This theoretically might allow people to use less acetaminophen, thereby reducing the risk of side effects. Consult with a doctor about this potential before reducing the amount of acetaminophen. However, increasing the time acetaminophen is in the body might also theoretically increase its toxicity. Consult with a doctor before taking vitamin C along with acetaminophen.