Want a jolt with that?

People craving a caffeine fix are finding an increasing number of unusual beverage options, including juice, water, and beer.

Companies such as Anheuser-Busch Cos. and PepsiCo Inc. are trying to capitalize on harried consumers' thirst for a pick-me-up by putting the natural stimulant in a variety of drinks.

The trend is partly driven by a boom in the energy drink category, which grew fivefold between 2001 and 2006 to $3.2 billion in sales nationally, according to the Mintel Group, a Chicago market research firm.

PepsiCo, for example, will soon begin selling a caffeinated fitness water, called Propel Invigorating Water. The company already has introduced caffeinated drinks to its SoBe juice line. Both new beverages have about as much caffeine as a regular Pepsi soda. Anheuser-Busch launched Bud Extra, a caffeinated beer, and Tilt, a caffeinated malt drink, two years ago.

Even energy drink brands are trying to pack more punch into their bottles and cans: Earlier this year, Monster Beverage Co. rolled out Java Monster, a line of coffee-flavored drinks. And rival Rockstar last year created Rockstar Juiced, an energy drink with mango, orange, passion fruit, and caffeine.

Despite the added kick, most of the drinks have less caffeine than brewed coffee. For example, Propel fitness water has 20 milligrams of caffeine per 8 ounces, compared with 128 milligrams in the same amount of coffee.

While many people still prefer a cup of coffee to start their mornings, Gary Hemphill, managing director of Beverage Marketing Corp., a New York research firm, said more consumers are demanding variety for their midday caffeine fix. Beverage companies are responding accordingly, he said.

"It's pointless to introduce a me-too product into the energy category," he said. "To have a shot at being successful, companies are introducing hybrid drinks like energy drinks with juice or coffee."

Pepsi and Coca-Cola are also adding new types of caffeinated drinks to their existing brands. Pepsi has introduced Diet Pepsi Max, which is Diet Pepsi with almost double the caffeine, while Coca-Cola created Tab Energy, an extension of the Tab diet cola that is geared toward women.

In 2006, women accounted for 23 percent of Coca-Cola's energy drink sales, Mintel said.

"What we found is that nearly 80 percent of Americans feel that maintaining energy is a priority throughout the day," said Nicole Bradley, a Pepsi spokeswoman. "So our decision is really in reaction. It's really about providing invigoration for people who need it during the work day."

There is no doubt that caffeine - a stimulant naturally found in chocolate, coffee beans, kola nuts, and tea leaves - increases alertness, said Dr. Michael Shannon, a pharmacologist and toxicologist at Children's Hospital in Boston. Soft drinks use sugar or other sweeteners to counteract its bitter taste.

While there are no serious long-term effects associated with moderate caffeine consumption, Shannon said he is concerned about the increase in the number of caffeinated drinks that may be popular with children, because they could disrupt sleeping patterns. He also worries about consumers becoming too dependent on a substance to make them alert.

"We are becoming an over-caffeinated society, and you have to wonder what the consequences of that would be," Shannon said.

Caffeinated alcoholic beverages have raised other concerns. In August, attorneys general representing 28 states, Washington, D.C., and Guam sent a letter to the Alcohol and Tobacco Tax and Trade Bureau criticizing advertisements promoting caffeinated alcoholic beverages such as Bud Extra and Tilt.

The drinks "do not mention the potentially severe, adverse consequences of mixing caffeine or other stimulants and alcohol," the letter said.

Francine Katz, Anheuser-Busch's vice president of communications and consumer affairs, said caffeinated alcoholic beverages are nothing new.

The company's new products, she said, were just a response to the changing demands of consumers.

Adding more caffeine, however, doesn't guarantee success. Last year, Coca-Cola launched a niche product called Coke Blak - a blend of Coke and coffee - but Hemphill said it will be discontinued.

That's not a surprise, he said, since less than half the drinks introduced to the market end up being successful.

Hemphill said he liked the strong coffee flavor of Coke Blak, but admitted it might not have appealed to a lot of people.

"It has a very bold flavor," he said. "People are either going to love it or not."