Also indexed as: Cafcit, Caffedrine, Enerjets, NoDoz, Quick
Pep, Snap Back, Stay Alert, Vivarin
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.
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
| 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.
Avoid: Adverse interaction—Avoid these supplements when taking this
medication because taking them together may cause undesirable or dangerous results.
Check: Other—Before taking any of these supplements or eating any of
these foods with your medication, read this article in full for details.
|Side effect reduction/prevention
An asterisk (*) next to an item in the summary indicates that the
interaction is supported only by weak, fragmentary, and/or contradictory scientific
Interactions with Dietary Supplements
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.
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
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
Smoking can increase caffeine metabolism,5 decreasing effectiveness. Smokers who
use caffeine-containing drug products may require higher amounts of caffeine to achieve
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
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.