Acetaminophen is used to reduce pain and fever. Unlike NSAIDs (nonsteroidal anti-inflammatory drugs), it
lacks anti-inflammatory activity. Acetaminophen is available by itself or in nonprescription
and prescription-only combination products used to relieve pain and the symptoms associated
with colds and flu.
Summary of
Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem
contradictory. For clarification, read the full article for details about the summarized
interactions.
May Be Beneficial:Side effect
reduction/prevention—Taking these supplements may help reduce the likelihood and/or
severity of a potential side effect caused by the medication.
Milk thistle*
NAC
May Be Beneficial:Supportive
interaction—Taking these supplements may support or otherwise help your medication
work better.
Vitamin C*
Avoid:Reduced drug absorption/bioavailability—Avoid these supplements
when taking this medication since the supplement may decrease the absorption and/or activity
of the medication in the body.
Hibiscus
Check:Other—Before taking any of these supplements or eating any of
these foods with your medication, read this article in full for details.
Schisandra
Depletion or interference
None known
Adverse interaction
None known
An asterisk (*) next to an item in the summary indicates that the
interaction is supported only by weak, fragmentary, and/or contradictory scientific
evidence.
Interactions with Dietary Supplements
NAC
Hospitals use oral and intravenous NAC (N-acetyl cysteine) to treat liver damage induced by
acetaminophen overdose poisoning.1 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.2 However, acetaminophen toxicity is a
potential medical emergency, and should only be managed by qualified healthcare
professionals.
Vitamin
C
Taking 3 grams vitamin C with acetaminophen has been shown to prolong the amount of time
acetaminophen stays in the body.3 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.
Interactions with Herbs
Hibiscus
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.4
Milk
thistle
Silymarin is a collection of complex flavonoids found in milk thistle (Silybum
marianum) that has been shown to elevate liver glutathione levels in rats.5
Acetaminophen can cause liver damage, which is believed to involve glutathione
depletion.6 In one study involving rats, silymarin protected against
acetaminophen-induced glutathione depletion.7 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.
Schisandra
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
depletion8 (unlike milk thistle, as reported above). Studies have not yet confirmed
this action in humans.
Interactions with Foods and Other Compounds
Food
Food, especially foods high in pectin (including jellies), carbohydrates, and large amounts of
cruciferous vegetables (broccoli, Brussels
sprouts, cabbage, and others) can interfere with acetaminophen absorption.9 It is
unclear how much effect this interaction has on acetaminophen activity.
Alcohol
Moderate to high amounts of acetaminophen have caused liver damage in people with
alcoholism.10 To prevent problems, people taking acetaminophen should avoid
alcohol.
References (To view, roll mouse over the "References" heading; to hide, click on the heading)
2. Perry HE, Shannon MW. J Pediatr 1998;132:149–52.
3. Houston JB, Levy G. Drug biotransformation interactions in man. VI:
Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218–21.
4. Kolawole JA, Maduenyi A. Effect of zobo drink (Hibiscus
sabdariffa water extract) on the pharmacokinetics of acetaminophen in human volunteers.
Eur J Drug Metab Pharmacokinet 2004;29:25–9.
5. Valenzuela A, Aspillaga M, Vial S, Guerra R. Selectivity of silymarin
on the increase of the glutathione content in different tissues of the rat. Planta
Med 1989;55:420–2.
6. Threlkeld DS, ed. Central Nervous System Drugs, Acetaminophen. In
Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Mar 1997,
247–f.
7. Campos R, Garrido A, Guerra R, Valenzuela A. Silybin dihemisuccinate
protects against glutathione depletion and lipid peroxidation induced by acetaminophen on rat
liver. Planta Med 1989;55:417–9.
8. Yamada S, Murawaki Y, Kawasaki H. Preventive effect of gomisin A, a
lignan component of schizandra fruits, on acetaminophen-induced hepatotoxicity in rats.
Biochem Pharmacol 1993;46:1081–5.
10. Threlkeld DS, ed. Central Nervous System Drugs, Acetaminophen. In
Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Mar
1997, 247–f.
The information presented in Healthnotes is for informational purposes
only. It is based on scientific studies (human, animal, or in vitro), clinical
experience, or traditional usage as cited in each article. The results reported may not
necessarily occur in all individuals. For many of the conditions discussed, treatment with
prescription or over the counter medication is also available. Consult your doctor,
practitioner, and/or pharmacist for any health problem and before using any supplements or
before making any changes in prescribed medications. Information expires June 2009.
