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Dangers of Energy Drinks Shown by Rise in Caffeine Toxicity Cases

Updated on November 15, 2016
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John uses Biochemistry and Physiology (PhD) skills to review health topics, disease prevention, home remedies for ailments & better health

Health professionals in Australia have suggested that revised warning labels be added to energy drinks containing caffeine following a sharp rise in the incidence of caffeine toxicity and overdoses, particularly from teenagers. Callers to the New South Wales Poisons Information Centre reported tremors, heart problems, stomach upsets, dizziness, irregular heart beat, jitters, chest pains and a number of other symptoms after drinking these beverages. Almost 300 calls were made reporting adverse reactions to energy drinks in the 7 years from 2004 - 2010, with more than 30% of these people attending hospital. The results from the study are summarised in the Table below adapted from the paper.

The number of call about caffeinated energy drinks increased five-fold from 12 to 65 from 2004 to 2010. Recreational use of caffeine was the most common reason for the call. The most common symptoms reported included stomach upsets, irregular heart rate, tremors and dizziness. In severe cases caffeine toxicity can resemble amphetamine poisoning,and cause psychosis, seizures, irregular heart beat and very rarely, death.

Teenagers were the most frequent group of callers. The energy drinks were often consumed with alcohol, amphetamines and other stimulants. More than half of the reported cases were male. 'Red Bull' and 'V' represented about 70% of the energy drink-related calls to the centre, followed by 'Mother' and 'Pulse'. No reports of caffeine toxicity caused by coffee or cola drinks occurred during study period. However nearly 550 people reported overdoses from the caffeinated tablets No-Doz and No-Doz Plus. Parents should be aware that many teenagers take these tablets because they cannot stay awake at night to play online games.

A typical can of energy drink can contain up to 300 mg of caffeine. The table shows the caffeine in a range of energy drinks available in Australia. Extra caffeine is added from additives such as guarana. In Australia the caffeine contents shown on the labels includes the total amount of caffeine including that in this and other additives. Guarana, an extract from the plant Paullinia cupana, contains caffeine, theophylline and theobromine in varying quantities. Guarana appears to have no apparent adverse effects other than that linked with the caffeine it contains. The amount of caffeine in guarana (40–80 mg per gram of extract) may not always declared on the packaging. Similarly, taurine, an amino acid added to many energy drinks, is not apparently toxic at the doses used. Ginseng, a herbal extract with claimed for its purported aphrodisiac and mild stimulant properties, has not been reported to be toxic at the dose used.

Caffeine Toxicity

Even a tiny dose of 50 mg of caffeine can induce agitation and rapid heartbeat. Some people may be allergic to caffeine at low dosages. Some manufacturers of energy drinks suggest a maximum of about 200 mg of caffeine per day. This is roughly 1 1/4 500 ml cans of energy drink such as 'Red Bull' or 'V'. The Red Bull website suggests that a person’s intake should be similar to that of coffee. Clearly mean teenagers and older people drink much more than this. The type of symptoms reported to the poison centre was consistent with an overdose of caffeine and stimulant misuse of a serious nature. About 60% of calls for advice came from emergency departments at hospitals. About 25% of the calls reported co-ingestion of alcohol and about 30% of calls reported co-ingestion of caffeine (including tablets) with other stimulants such as amphetamines.

Various studies of American college students have warned of the dangers of the mixing of energy drinks with alcohol, particularly in an attempt to sober up. See Energy Drinks: Side Effects, Health Concerns, Dangers with Alcohol

Caffeine Overdose Symptoms

The recommended a safe amount of caffeine is about 300-500 milligrams of caffeine per day. This is of course depends on health, body weight, tolerance through repeated use and individual sensitivity. This is equivalent to about 4 cups of coffee a day or 2-3 energy drinks. Caffeine intake beyond 500 mg per day has been shown in various studies to cause insomnia, nervousness and headaches, but it varies a lot. Caffeine takes some time to work through the body and them is broken down and eliminated. The half-life of caffeine in adults is about 6 hours. This means if you consume 200 mg of caffeine at 6.00am, you would still have 100 mg in your system at noon.

There are a variety of common symptoms that indicate too much caffeine has been consumed. The body can work to metabolise the caffeine in the body and so the dose depends on the rate of ingestion. Consuming massive doses of caffeine all at once is dangerous because there is not enough time for the warning symptoms to develop showing that too much caffeine has been consumed. The common symptoms of potential overdose are:

  • Jitters
  • Nausea
  • Vomiting
  • Increased heartbeat
  • Heart palpitations
  • Anxiety
  • Sweating
  • Insomnia
  • Dizziness
  • Cardiac arrest (rare)

© janderson99-HubPages


There is clear evidence of caffeine toxicity caused by over-consumption. The growing number of hospitalisations, particularly in teenagers has suggested that the labels on energy drinks should be improved and regulation imposed controlling caffeine content. The authors of the study recommend that labelling should include National Poisons hotline number and appropriate health warnings. Warning labels similar to those used on as non-prescription caffeine tablets should be used on energy drinks. The labels used for No Doz are shown below.

Cases of Caffeine Toxiity Reported to NSW Poison Centre

Main ingredients, dose/100 mL
Serving volume (mL)
Total Caffeine per serving
No. of calls
Red Bull
Caffeine, 32mg
Sugars, 11g
Caffeine, 32mg
Guarana extract, 120mg
Ethanol, 7g
Caffeine, 7mg
Caffeine, 32mg
Sugars, 10.5g
Caffeine, 32mg
Guarana extract, 10mg
Ginseng extract, 20mg
Sugars, 13g
Other/ unknown
Cola drinks
Caffeine, approximately 40mg per can (11mg per 100ml)
no cases
Caffeine, approximately 25-200mg per cup
no cases
No-Doz/No-Doz Plus
Caffeine, 100mg / tablet (packs of 24, and 100)

© 2012 Dr. John Anderson


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  • profile image

    Apemania 5 years ago

    Personally I only drink low-quality energy drinks and never when i'm thirsty, only to get a nice kick in the head and become a little more awake.

    I don't know if this is true or not, but I remember a story about some jogger dude that was really parched during a jogging thing, he downed two red bulls in a row and ran on. He later collapsed and died of heart failure. If that's true, then becomes a little tragic. I guess it wasn't really what he wanted, to jog himself to the other side. Abusing energy drinks isn't really good anyway.

    As long as you don't drink energy drinks as if they were water, then I guess in only extreme cases something bad can happen. Before I forget, nice hub =).

  • pippap profile image

    pippap 5 years ago from Surrey, BC

    Good hub. Loaded with information and easy to read. Energy drinks are on my "hit" list as well. Disaster in a can, I think.

  • CWanamaker profile image

    CWanamaker 6 years ago from Arizona

    Yeah caffeine can be dangerous, but people just need to be cautious and read the warning labels. I have been consuming energy drinks and caffeine pills for years with no ill effects. These days I average between 400-500mg of caffeine a day. However it wasn't too long ago that I consumed much more than this. I even chewed caffeinated gum and drank caffeinated water, Great hub, people need to be aware of the consequences of too much caffeine,