'Tear into a can of the meanest energy drink on the planet . . . unleash the beast!" Fast-paced, brash marketing has helped build a multi-billion-dollar global energy drink industry which barely existed 20 years ago. But the spotlight has fallen on Monster - a caffeinated drink whose slogan is "unleash the beast" - after the death of a teenage girl in the US.
Anais Fournier, 14, died of a heart attack in December after drinking two big cans of Monster in the space of less than two days. Her parents are suing the makers of Monster, claiming that caffeine in the drink, combined with an existing and diagnosed heart condition, led to her death. Monster, which is sold under licence in Australia by Schweppes, contains about 32mg of caffeine in every 100ml.
Anais drank about 1.4 litres of Monster over two days, consuming about 480mg of caffeine from two 709ml resealable cans. That size can is not available in Australia, where Monster is limited to 500ml cans. According to Food Standards Australia and New Zealand calculations of caffeine content, Anais drank the equivalent of six to eight cups of instant coffee, which contain 60 to 80mg of caffeine, or almost ten 375ml cans of Coca-Cola.
US authorities are also considering four other incidents which may be linked to the energy drinks. The US makers of Monster strenuously deny that their product has any causal link to Anais' death.
A spokeswoman for Schweppes, which makes Monster in Australia, said the energy drink market was tightly regulated. She said the cans were labelled with warnings that they were not suitable for children, pregnant women or those sensitive to caffeine and people should drink a maximum of one can per day.
So should users of energy drinks in Australia be concerned?
"We would certainly be urging caution," cardiologist John O'Shea, president of the Heart Foundation's WA division, said.
"We have had this experience locally and these energy drinks can be a trap if people over-indulge."
High doses of caffeine could stimulate erratic rhythms of the heart, including palpitations. In some cases, this could be fatal, he said.
"The promotion of these seems to be targeted at young people. Really, the makers of these drinks need to be more responsible in terms of how they promote them."
The Drug and Alcohol Office of the WA Department of Health lists caffeine's short-term effects as increased alertness, energy, metabolism, blood pressure and body temperature, altered mood and increased urination. Its effects depend on mood, physical size, gender and whether the person using it has taken other drugs. It estimates the average adult consumes about 70mg of caffeine per day, but warns that the effects of big doses of 600mg or more - about ten cups of coffee or three to four 500ml cans of Monster - can cause headaches, hand tremors, impaired coordination, nervousness, diarrhoea and delirium.
Regular users can suffer chronic insomnia, depression, stomach upset, persistent anxiety and heart palpitations. Food Standards Australia and New Zealand said there was no recognised acceptable daily intake for caffeine. But it said there was evidence caffeine could increase anxiety levels among children aged five to 12 who consumed 95mg of caffeine, equivalent to about two cans of Coca-Cola or 300ml of Monster.
It noted that 210mg of caffeine - three cups of coffee or about 650ml of Monster - could have a similar effect on adults.
There is also a misconception that energy drinks can significantly improve sporting performance - probably thanks to clever marketing and TV coverage in 2010 which showed AFL players taking caffeine pills in changerooms before a match.
The DAO noted that some young people were consuming energy drinks as if they were soft drinks or water. Some thought they needed to drink the maximum recommended dose to obtain the maximum benefit, rather than seeing the dose as an upper limit.
Steve Allsop, director of the National Drug Research Institute at Curtin University, said people often used more than one source of caffeine.
"When you talk about energy drinks it's worth reminding of the cumulative amount of caffeine that you consume," Professor Allsop said.
"You can't just point to energy drinks. Very often you find people are using several of these, including caffeine tablets." Tablets such as No-Doz were attractive because, unlike 500ml cans of energy drinks, they were very portable. "It's the cumulative effect that is the issue. Caffeine is a drug and it does have the potential for harm, particularly in high doses." With WACE exams due to start tomorrow, Professor Allsop warned students against relying on caffeine. He said taking caffeine might help students stay awake longer so they could study more but it could affect their ability to recall information if they were not properly rested.
"The ability to pull that information out can be impaired if your sleep is disrupted," he said.
He likened losing sleep to a credit card. You can take out what you want, but you have to pay it back some time.
The website for No-Doz includes Tips For Better Memory section. It lists rote and associative learning and advises students to eat a good breakfast. Tellingly, the section does not cite caffeine.
The use of stimulants by students is not limited to energy drinks and over-the-counter pills. Last week, Paul Skerritt, the Australian Medical Association's psychiatry spokesman, said students had asked doctors to prescribe dexamphetamines to "tide (them) over for the exams".
Energy drink makers also market the perceived benefits of other ingredients, including taurine, an amino acid sometimes taken as a dietary supplement which has been shown in some studies to improve athletic performance.
Others include pantothenic acid, also known as Vitamin B5, and supplements such as inositol and glucuronolactone, which scientists say have few benefits or adverse effects in the quantities that exist in energy drinks.'Really the makers of these drinks need to be more responsible.'