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.1 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.2 However, in 138 healthy postmenopausal women, long-term dietary caffeine (coffee) intake was not associated with bone density.3 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.4 Acetaminophen can cause liver damage, which is believed to involve glutathione depletion.5 In one study involving rats, silymarin protected against acetaminophen-induced glutathione depletion.6 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.
Food, especially foods high in pectin (including jellies), carbohydrates, and many types of cruciferous vegetables (broccoli, Brussels sprouts, cabbage, and others) can interfere with acetaminophen absorption.7 It is unclear how much effect this interaction has on acetaminophen activity.
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.8
Food, especially foods high in pectin (including jellies), carbohydrates, and many types 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.
Until 2004, many herbal weight loss and quick energy products combined caffeine or caffeine-containing herbs with ephedra. This combination may lead to dangerously increased heart rate and blood pressure and should be avoided by people with heart conditions, hypertension, diabetes, or thyroid disease.11
Caffeine is found in coffee, tea, soft drinks, and chocolate. To reduce side effects, people taking caffeine-containing drug products should limit their intake of caffeine-containing foods/beverages.
Hospitals use oral and intravenous NAC to treat liver damage induced by acetaminophen overdose poisoning.12 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.13 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 depletion14 (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.15 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.16
1. Harris SS, Dawson-Hughes B. Caffeine and bone loss in healthy postmenopausal women. Am J Clin Nutr 1994;60:573–8.
2. Barrett-Connor E, Chang JC, Edelstein SL. Coffee-associated osteoporosis offset by daily milk consumption. The Rancho Bernardo Study. JAMA 1994;271:280–3.
3. Lloyd T, Rollings N, Eggli DF, et al. Dietary caffeine intake and bone status of postmenopausal women. Am J Clin Nutr 1997;65:1826–30.
4. 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.
5. Threlkeld DS, ed. Central Nervous System Drugs, Acetaminophen. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Mar 1997, 247–f.
6. 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.
7. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 2.
8. 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.
9. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 2.
10. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 2.
11. Tyler VE. Herbs of Choice: The Therapeutic Use of Phytomedicinals. New York, Pharmaceutical Press, 1994, 88–9.
12. Vale JA, Proudfoot AT. Paracetamol (acetaminophen) poisoning. Lancet 1995;346:547–52.
13. Perry HE, Shannon MW. J Pediatr 1998;132:149–52.
14. 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.
15. Houston JB, Levy G. Drug biotransformation interactions in man. VI: Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218–21.
16. FDA Information on Acetaminophen, Jan 13, 2011. http://www.fda.gov/Drugs/DrugSafety/InformationbyDrugClass/ucm165107.htm
Last Review: 05-01-2013
Copyright © 2013 Aisle7. All rights reserved. Aisle7.com
Please read the disclaimer about the limitations of the information provided here. Do NOT rely solely on the information in this article. The Aisle7 knowledgebase does not contain every possible interaction.
The information presented in Aisle7 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 2014.
Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.