Memo: caffeine & acetaminophen don't play nice

In case news of this study hasn't crossed your path yet, here's something for all you caffeine addicts to pay a little attention to: a recent study would have you believe that combining caffeine with acetaminophen might not be so good for you.

Consuming large amounts of caffeine while taking acetaminophen, one of the most widely used painkillers in the United States, could potentially cause liver damage, according to a preliminary laboratory study reported in the Oct. 15 print issue of ACS’ Chemical Research in Toxicology, a monthly journal. The toxic interaction could occur not only from drinking caffeinated beverages while taking the painkiller but also from using large amounts of medications that intentionally combine caffeine and acetaminophen for the treatment of migraine headaches, menstrual discomfort and other conditions, the researchers say.

Health experts have warned for years that consuming excess alcohol while taking acetaminophen can trigger toxic interactions and cause liver damage and even death. However, this is the first time scientists have reported a potentially harmful interaction while taking the painkiller with caffeine, the researchers say.

Now before you take these claims at face value (which of course is exactly the kind of thing I always do), let's see what Drugs and Poisons has to say on this subject:

The investigators used doses of acetaminophen and caffeine that far exceed the levels of typical daily consumption of these drugs by most people, so even if CYP 3A4 does indeed convert acetaminophen into a toxic metabolite and caffeine enhances this process, it is likely only relevant to a small group of people: Those who take too much Tylenol on a regular basis AND consume coffee like a marathon runner consumes water.

Whew, that was close!