Caffeine Health Article

Pregnancy

Caffeine can pass from a pregnant woman's body into the developing fetus. Although there is no evidence that caffeine causes birth defects in people, it does cause such effects in laboratory animals given very large doses (equal to human doses of 12-24 cups of coffee a day). In humans, evidence exists that doses of more than 300 mg of caffeine a day (about the amount of caffeine in two to three cups of coffee) may cause miscarriage or problems with the baby's heart rhythm. Women who take more than 300 mg of caffeine a day during pregnancy are also more likely to have babies with low birth weights. Any woman who is pregnant or planning to become pregnant should check with her physician before using caffeine.

Breastfeeding

Caffeine passes into breast milk and can affect the nursing baby. Nursing babies whose mothers use 600 mg or more of caffeine a day may be irritable and have trouble sleeping. Women who are breast-feeding should check with their physicians before using caffeine.

Other medical conditions

Caffeine may cause problems for people with these medical conditions:

• peptic ulcer
• heart arrhythmias or palpitations
• heart disease or recent heart attack (within a few weeks)
• high blood pressure
• liver disease
• insomnia (trouble sleeping)
• anxiety or panic attacks
• agoraphobia (fear of being in open places)
• premenstrual syndrome (PMS)

Side effects

At recommended doses, caffeine can cause restlessness, irritability, nervousness, shakiness, headache, light- headedness, sleeplessness, nausea, vomiting, and upset stomach. At higher than recommended doses, caffeine can cause excitement, agitation, anxiety, confusion, a sensation of light flashing before the eyes, unusual sensitivity to touch, unusual sensitivity of other senses, ringing in the ears, frequent urination, muscle twitches or tremors, heart arrhythmias, rapid heartbeat, flushing, and convulsions.

Interactions

Using caffeine with certain other drugs may interfere with the effects of the drugs or cause unwanted— and possibly serious—side effects. Certain drugs interfere with the breakdown of caffeine in the body. These include oral contraceptives that contain estrogen, the antiarrhythmia drug mexiletine (Mexitil), the ulcer drug cimetidine (Tagamet), and the drug disulfiram (Antabuse), used to treat alcoholism.

Caffeine interferes with drugs that regulate heart rhythm, such as quinidine and propranolol (Inderal). Caffeine may also interfere with the body's absorption of iron. Anyone who takes iron supplements should take them at least an hour before or two hours after using caffeine.

Serious side effects are possible when caffeine is combined with certain drugs. For example, taking caffeine with the decongestant phenylpropanolamine can raise blood pressure. Very serious heart problems may occur if caffeine and monoamine oxidase inhibitors (MAO) are taken together. These drugs are used to treat Parkinson's disease, depression, and other psychiatric conditions. Consult with a pharmacist or physician about which drugs can interact with caffeine.

Because caffeine stimulates the nervous system, anyone taking other central nervous system stimulants should be careful about using caffeine.

KEY TERMS

Arrhythmia—Abnormal heart rhythm.

Central nervous system (CNS)—The brain, spinal cord, and nerves throughout the body.

Decoction—An herbal extract produced by mixing an herb in cold water, bringing the mixture to a boil, and letting it simmer to evaporate the excess water. The decoction is then strained and drank hot or cold. Decoctions are usually chosen over infusion when the botanical or herb in question is a root, seed, or berry.

Palpitation—Rapid, forceful, throbbing, or fluttering heartbeat.

Tinctures—A liquid extract of an herb prepared by steeping the herb in an alcohol and water mixture. Tinctures can also be prepared using vinegar or glycerin, instead of alcohol.

Withdrawal symptoms—A group of physical or mental symptoms that may occur when a person suddenly stops using a drug to which he or she has become dependent.

BOOKS

Hoffman, David. The Complete Illustrated Herbal. New York:

Barnes & Noble Books, 1999.

Medical Economics Corporation. The PDR for Herbal Medicines. Montvale, NJ: Medical Economics Corporation, 1998.

ORGANIZATIONS

Office of Dietary Supplements. National Institutes of Health.

Building 31, Room 1B25, 31 Center Drive, MSC 2086, Bethesda, MD 20892-2086. (301) 435-2920. Fax: (301) 480-1845. <http://odp.od.nih.gov/ods/> (Includes on-line access to International Bibliographic Information on Dietary Supplements (IBIDS), a database of published, international scientific literature on dietary supplements and botanicals).

Paula Ford-Martin