Caffeine containing beverages and plants have been used medicinally for thousands of years, beginning with the Aztecs. The six most widely used caffeine-containing plants in the world are: cacao, coffee, guarana, kola, mate and tea.
Use: The most common uses are used to treat headaches and migraines, increase mental alertness, treat asthma and enhance athletic performance. It is often used in combination with ephedrine (ephedra or Ma Huang) or other stimulants and diuretics (water pills) to promote weight loss.
Dosage: The dosage recommended for athletic performance is 6-13 milligrams per kilogram of body weight taken 30-60 minutes prior to exercise. A typical dose to treat headache or increase mental alertness is up to 250 milligrams per day.
Potential Side Effects: Caffeine can cause insomnia, nervousness, restlessness, gastric(digestive system) irritation, nausea and vomiting, tachycardia (excessively rapid increase in heart rate), increased respiration, tremors (involuntary shaking), delirium (acute mental disorder characterized by disordered thinking and rambling speech), convulsions and diuresis (increased excretion of urine).
Large doses can produce headache, anxiety, agitation, ringing in the ears and abnormal heartbeat.
Long-term use of caffeine, especially in large amounts, can sometimes produce tolerance, dependency and psychological dependence. Discontinuing use of caffeine can sometimes result in physical withdrawal symptoms, including headaches, irritation, nervousness, anxiety and dizziness. Side effects of caffeine use are often increased by the use of other caffeine-containing herbs/ supplements such as guarana and mate. Use of caffeine-containing beverages - coffee, cola and black teas - along with oral caffeine can greatly increase the side effects. Delirium can occur with intake over 1,000 milligrams per day and death can occur with intake over 18,000 milligrams per day.
Interactions: The following list of drugs when used with caffeine can increase the risk of caffeine-related side effects:
2) disulﬁram (Antabuse)
3) estrogen (Estrace)
4) terbinaﬁne (lamisil)
5) ﬂuvoxamine (Luvox)
6) mexiletine (Mexitil)
7) oral contraceptives (birth control pills)
8) quinolones (Cipro, Penetrex, Tequin, Levaquin, Floxin, etc.)
9) riluzole (Rilutek)
10) cimetidine (Tagamet)
11) verapamil (Calan, Isoptin, Verelan)
Caffeine can increase the side effects of:
1) albuterol (Proventil, Ventolin)
2) metaproterenol (Alupent)
3) ephedrine (Ephedra, Ma Huang)
4) phenylpropanolamine (Dexatrim, Propagest)
5) lithium (Eskalith, Lithobid)
6) MAO inhibitors (Nardil, Parnate and others)
7) methylphenidate (Ritalin)
8) theophylline (Theo-dur)
9) riluzole (Rilutek)
Caffeine may decrease the effectiveness of:
1) clozapine (Clozaril)
2) clorazepate (Tranxene)
3) oxazepam (Serax)
4) diazepam (Valium)
Contraindication to Use: Heart disease, depression or anxiety disorders, diabetes, high blood pressure, kidney disease, peptic ulcer disease, and pregnancy (further guidance concerning pregnancy recommendations can be obtained at www.acog.org). It is not recommended for children.
Research Data on Safety and Efﬁcacy: Caffeine is a safe product when used in moderation. Research shows that it may improve performance in prolonged exercise at moderate intensity. However, there is no beneﬁt for routine, high dose caffeine users (i.e., 5-6 cups of coffee per day). It is FDA-approved and is used in several over-the-counter and prescription products. The International Olympic Committee bans use of caffeine in excess of 7 milligrams per kilogram body weight.
1. Tyler’s Honest Herbal, 4th Edition. Steven Foster, and Varro E. Tyler, PhD. 1999.
2. The Natural Medicines Comprehensive Database, 4th Edition. Jeff M. Jellin, Pharm D, Therapeutic Research Facility, 2002.
Bottom Line: Caffeine is safe when used in moderate, reasonable amounts. Consult a health care provider, registered dietitian or pharmacist when considering using caffeine-containing products in combination with prescription medications or herbal supplements.