One can over the course of an hour was all the 28-year-old needed to feel sicker than she’s ever felt, crouched over the toilet bowl vomiting for the next eight hours.

“I woke up the next morning puking for probably like six or eight hours until late afternoon, just throwing up every half hour I felt so ill, I couldn't keep any food down,” she said. “It was one of the worst hangovers of my life and I've been drinking for 12 years…I definitely swore off of it. I will never drink it again.”

It started the night before. Greenwood and a few of her friends purchased cans of Four Loko at a nearby 7/11 to loosen up before a night of summer barhopping in Chicago.

But Greenwood barely lasted at the bars before blacking out. Friends took her to an apartment close by. Once there, she started crying and vomited off a balcony.

“I just needed one drink to have at this party before we went to bars and I thought, ‘How bad can one can of any drink be?’” she said. “I thought, ‘This is about the size of two beers. It's an energy drink, it'll wake me up, this'll be great, and I didn't think much beyond that.”

The caffeinated alcoholic beverage commonly referred to as a "blackout in a can" is making waves on college campuses and beyond where people are "getting Loko.”

While medical officials decry the drink’s dangers, a very vocal contingent is defending it, calling for underage drinkers to simply be responsible.

The debate has brought the drink, its 12 percent alcohol content and its manufacturers into the limelight in recent weeks as state after state takes action to ban the beverage from shelves.  

The FDA is expected to rule on its status as a safe and legal beverage as soon as Wednesday, concluding a year-long review of the drinks.

Michigan, Oklahoma, Utah and Washington have already prohibited vendors from stocking and selling Four Loko. Other states are weighing a ban on the sale of these drinks.

Massachusetts regulators announced a ban on Monday, and some beer distributors in New York agreed to a voluntary ban on Saturday. The Pennsylvania Liquor Control Board has discouraged vendors from selling the beverage until the FDA rules on its safety. The Chicago City Council is also reportedly looking into a ban.

Attorney generals in 18 states, including California, have urged the FDA to look into the safety of the drinks, recommending the "immediate removal of [Alcoholic Energy Drinks] from the marketplace."

The caffeine-laced alcoholic beverages have become popular on college campuses since first marketed in 2005.

Nine underage students at Central Washington University were hospitalized in October for reportedly becoming "dangerously ill" from drinking "large amounts" of Four Loko at an off-campus party.

More than 20 students have been hospitalized for Four Loko-related incidents at Ramapo College in New Jersey. The school has since banned the drink.

Other schools including Harvard University, Lebanon Valley College in Pennsylvania and the University of Rhode Island are warning students of the dangers of the beverage or prohibiting it on campus.

College officials at Elizabethtown College in Pennsylvania are attempting to discourage drinkers by stressing its caloric value, which hovers somewhere between 600 and 800 calories.

One 23.5-ounce can of Four Loko is said to contain the equivalent of four or five beers and the caffeine in two cups of coffee.

The drink's manufacturer, Phusion Projects Inc., has repeatedly defended its product, issuing statements after the incident at Central Washington University and after various state bans.

“No one is more upset than we are when our products are abused or consumed illegally by underage drinkers – and it appears that both happened in [the CWU] instance. This is unacceptable. But so too is placing blame for the incident squarely on Four Loko when the police report, toxicology reports and witness testimony all show that other substances, including beer, hard liquors like vodka and rum, and possibly illicit substances, were consumed as well,” the company said in a statement about CWU.  

To enter Four Loko’s website, visitors have to enter their birth date to ensure they are 21 years of age and confirm their birth year, and then are prompted by a pop-up window to read an open letter to state and federal regulators from Phusion Projects. The company has also added a “Responsible Drinking” section to its site in light of recent media and government attention.

In the open letter, the company’s founders write, “While we don’t agree with the notion that mixing caffeine and alcohol is inherently unsafe, we do agree with the goal of keeping adults of legal age who choose to drink responsibly as safe and as informed as possible.”

FDA spokesman Michael L. Herndon said the agency notified manufacturers of caffeinated alcoholic beverages in November 2009 that it was looking more closely into the safety of the beverages.

Though the process is still underway, Herndon said the agency’s official position is that these beverages are not generally recognized as safe.

“In most cases food products do not require pre-market approval from FDA,” Herndon said.

The FDA is currently reviewing the 19 responses it got to its letter, which was sent to 27 manufacturers, asking them to support their position that the drink is safe. United Brands Company, Inc., which makes Joose, Diageo North America, Inc., which makes Smirnoff Raw Tea Malt Beverage and The P.I.N.K. Spirits Company/Prohibition Beverage Inc., which makes P.I.N.K. Vodka, were among the recipients of the FDA's letter.

The drink's 12 percent alcohol content, when combined with caffeine and other ingredients, has experts and medical officials worried.

“I would  certainly favor banning the stuff or putting more significant controls on it so it doesn't fall in the hands of inexperienced drinkers,” said Dr. Jeff Baldwin, a professor at the University of Nebraska Medical Center College of Pharmacy and a substance abuse educator. “I don’t know why they get away with putting a 12 percent concentration in a 24-ounce can. I call that a timebomb in a can.”

Baldwin stressed that one big issue with drinks like Four Loko is how fast people drink them. 

“It's like a 6-pack of beer in a can or a liter of wine—nobody in their right mind would think about drinking a liter of wine in an hour and yet these kids are drinking a full can,” he said.

Greenwood said once she opened the can, she wasn’t going to throw it away.

“I had just spent money on it, so I was going to drink it no matter how bad it tasted.”

On a normal night, Greenwood said she would not have more than four or five drinks.

“But this felt like more than four or five drinks to me. I wasn't prepared for it. I feel silly that I wouldn't look into [the alcohol content] more or considered that more, but I think because it was an energy drink…I thought, ‘I can handle this.’”

Deborah Feller, a New York psychotherapist dealing with alcohol and substance abuse and dependency, said one of the biggest risks with a drink like Four Loko is the mixture of the caffeine, a stimulant, and the alcohol, a central nervous system depressant.

“When you put caffeine in with alcohol you can drink more alcohol without being put to sleep, and you're in much more danger of OD'ing and getting ill or dying,” she said. “It doesn't get more dangerous than that because you're not feeling the effects of the alcohol because the caffeine is acting as a stimulant or an antidote.”

Baldwin refers to the combination’s effects as an “awake drunk.” 

“The old wives tale of drinking coffee to sober you up is not true,” he said. “All it does is make you a more awake person who is still equally impaired. You're just not sleeping.”

Officials are also worried about the product’s marketing.

“This is not a product that a 45-year-old person is typically going to pick up and say, ‘Hey, I'll try this,’” Baldwin said. “This is something teenagers will be attracted to because they've been brought up on pop, fruit drinks and Kool-Aid. Most drinkers will mature to regular beer or scotch or whiskeys or a gin or something like that but kids don't just start out drinking gin.”

A student at the University of Southern California who wishes to remain anonymous because she’s underage said she’s vowed never to have Four Loko again after a bad experience with the beverage.

“It was unreal how quickly I was drunk, it scared me a little,” she said. “Because it has so much energy in it you go into this weird state between being really drunk and being really energetic.”

Though she’d consumed the drink once before, the second time she used it in a game of beer pong, consuming a can in about a half an hour.

She said she spent the next morning vomiting and can’t look at an energy drink without getting nauseated.

“I thought I had been roofied,” she said. “It was the worst hangover of my life.” 

Most of her friends who drink Four Loko “like to blackout,” she said.

And it’s this habit that experts are pointing to as one of the chief dangers behind the beverage.

“An adolescent brain is still developing and the only place in our society that seems to get that are the car rental companies who don't rent cars to people who are under 25,” Feller said. “People who are at an adolescent stage of development they feel immortal…so now you're going to give them something exciting to do, something new, something different, and they lack the judgment.” 

Websites and parodies have sprung up in light of the drink’s recent popularity.

Fourlokostories.com serves as a forum for visitors’ best Four Loko stories.

Some examples:

4loko runaway: i seem to have a reoccurring incident with fourlokos whenever i drink them each time i black out and try to leave wherever i am naked and drive home. loco for lokos!!!
beckster: I had a mixture of a few different Four Lokos and ended the night in the ER with a broken ankle, singing Juicy by Notorious B.I.G to everyone.

The site has its own “Four Lokator,” which tracks where in the U.S. bans have been placed on the beverage.

But many college students are criticizing the bad rap the drink has gotten and are making the case that drinking Four Loko is just like drinking any other kind of alcohol—it has to be done responsibly.

“On Four Loko cans, it is clearly stated that the drink contains caffeine and is 12 percent alcohol by volume. If you are capable of absorbing this information and choose to consume said drink anyway, you should be prepared to take responsibility for whatever repercussions may arise from your consumption," writes the editorial staff of the student newspaper at the State University of New York at Geneseo.

Though some use the drink as a pregame—or warmup—before drinking other kinds of alcohol, one 19-year-old USC student, said she and her friends know their limits.

“If I’m drinking Four Loko, that’s my drink for the night and I’m sipping it.”

A student at Columbia College’s Columbia Spectator wrote, “Four Loko is the fast food of alcoholic beverages. It’s unhealthy and widely available. It’s also quick, cheap and, to some, a satisfying if shamefully hedonistic indulgence. Sure, Four Loko isn’t the best for you. Neither is fast food, but would you want a law denying you the occasional greasy burger?”

To reach editor-in-chief Callie Schweitzer, click here.
To follow her on Twitter: @cschweitz
Sign up for Neon Tommy's weekly e-mail newsletter.