Granted, she drank 48 oz of the stuff, which is a lot of anything to drink, but how much caffeine is in that stuff, say, compared to Mt Dew or a similarly high caffeine soft drink? I didn't know that large amounts of caffeine could cause arrythmia. I can think of a few people who drink over half a gallon of coffee per day.
Looked it up. Interesting note from wikipedia page on monster
"The caffeine content of most Monster Energy drinks is approximately 10 mg/oz (33.81 mg/100ml),[6][7] or 160 mg for a 16 oz can. The packaging usually contains a warning label advising consumers against drinking more than 48 oz per day (16 oz per day in Australia). The UK and Europe do not have these warning labels. The drinks are not recommended for children, pregnant women or people sensitive to caffeine.
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As for how that compares with coffee, mcdonalds coffee is 100mg per 16 oz and starbucks Pike place coffee is 330 mg per 16 oz, so monster is not extremely high in caffeine. It does contain other crap that is probably worse for you, and they deliberately obscure the caffeine amount on their ingredients label by lumping it in with other ingredients.