Also indexed as: Cafcit, Caffedrine, Enerjets, NoDoz, Quick Pep, Snap Back, Stay Alert, Vivarin
Combination drugs: Anacin, Darvon Compound, Fioricet, Fiorinal
Caffeine is a central nervous system stimulant drug used as an aid to stay awake, for mental alertness due to fatigue, and as an adjunct with other drugs for pain relief. Caffeine is available alone as a nonprescription drug, in combination with other nonprescription drugs, and in prescription drug combinations for relief of pain and headache.
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: Depletion or
interference—The medication may deplete or interfere with the absorption or
function of the nutrient. Taking these nutrients may help replenish them. |
Calcium |
Avoid: Adverse interaction—Avoid these supplements when taking this
medication because taking them together may cause undesirable or dangerous results. |
Ephedra Tobacco |
Check: Other—Before taking any of these supplements or eating any of
these foods with your medication, read this article in full for details. |
Guaraná |
| Side effect reduction/prevention |
None known |
| Supportive interaction |
None known |
| Reduced drug absorption/bioavailability |
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
Calcium
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).
Interactions with Herbs
Guaraná (Paullinia cupana)
Guaraná is a plant with a high caffeine content. Combining caffeine drug products and
guaraná increases caffeine-induced side effects.
Ephedra
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.4
Interactions with Foods and Other Compounds
Food
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.
Tobacco
Smoking can increase caffeine metabolism,5 decreasing effectiveness. Smokers who
use caffeine-containing drug products may require higher amounts of caffeine to achieve
effectiveness.
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. Tyler VE. Herbs of Choice: The Therapeutic Use of Phytomedicinals. New York, Pharmaceutical Press, 1994, 88–9.
5. Joeres R, Klinker H, Heusler H, et al. Influence of smoking on caffeine elimination in healthy volunteers and in patients with alcoholic liver cirrhosis. Hepatology 1988;8:575–9.