Stimulant Package

April 1, 2009
Buzzed: The Straight Facts About the Most Used and Abused Drugs from Alcohol to Ecstasy

Buzzed: The Straight Facts About the Most Used and Abused Drugs from Alcohol to Ecstasy has a lot to say about stimulants. The book, now in its third edition (W.W. Norton), was written by a team of Duke medical scientists and others primarily as a resource for teens, college students, parents, and health educators.

While they succinctly review substances like Ritalin, the Buzzed team devotes a full chapter to caffeine. Caffeine is a good example, they write, of how a drug can produce an effect—in this case, stimulating the central nervous system—by "inhibiting the action of a neurotransmitter that produces an inhibiting effect." That is, it reduces the ability of a natural "brake" on neural activity to do its job. Among other effects,
caffeine can increase heart rate, breathing, and blood pressure and create dependence. The authors note that it can also "slightly enhance physical endurance and delay fatigue associated with vigorous exercise in some people." Americans are consuming more varieties of coffee and coffee drinks than ever before, they write. "It is estimated that more than 50 percent of Americans drink coffee every day—as many as three to four cups each."

The amount of caffeine in a cup of coffee varies tremendously and depends on the type of coffee bean, the method of roasting, and the fineness of grind and method of brewing. Espresso is an especially complex concoction: A cup of espresso contains about one and a half to two fluid ounces, much less than
a typical cup of coffee. But espresso contains more caffeine per fluid ounce than coffee, so the amounts of caffeine in a cup of coffee and a cup of espresso are about the same.

Energy drinks are relatively new: Red Bull was introduced into the U.S. in 1997. But they have been "marketed aggressively to young people and have obviously been successful," the authors write. One element of their popularity may relate to how the drinks are consumed. "Unlike caffeinated beverages that are hot and are generally sipped slowly, energy drinks tend to be consumed quickly, thus leading to more rapid absorption of the caffeine (and other chemicals) and a more rapid buzz."

The term "energy drink" is not exactly accurate, the authors observe. The concentration of caffeine in these products is often twice as high as in regular caffeinated sodas, though the serving sizes are smaller—about eight and a half ounces, compared with twelve ounces for a regular soda—and most come in smaller containers.

"Interestingly, although these drinks have the reputation of providing a big caffeine blast, they actually contain about the same concentration of caffeine as coffee—maybe even a bit less," the authors say.

Among the Buzzed authors are Cynthia Kuhn Ph.D. '76, professor of pharmacology at Duke Medical Center; Scott Swartzwelder, professor of psychology and a clinical professor of psychiatry at the medical center; and Wilkie Wilson Ph.D. '71, professor of pharmacology at the medical center.