Thinking of popping a Tylenol? A new study suggests you may want to save yourself some money and take a sugar pill instead. Researchers looked at the usefulness of acetaminophen in managing low back pain and osteoarthritis of the hip or knee—and they found that in such cases, the drug works no better or, at most, only slightly better than a placebo. Specifically, acetaminophen was ineffective in helping with low back pain and only minimally beneficial—not enough to be considered clinically significant—for managing osteoarthritis, according to the study published in BMJ. The findings are significant, researchers note, since acetaminophen is generally recommended as the "first line analgesic" in these cases.
"The American guidelines were published in 2007, when the evidence was weaker," the study's senior author explains to the New York Times. "It is time to review the recommendations." The researchers looked at a number of trials involving a total of 5,366 patients; oral dosage varied from 3000mg per day to 4000mg per day (one trial involved an IV dose of 1000mg). Tylenol currently recommends no more than 3000mg per day, down from the previous recommendation of 4000mg. The study also suggests that taking acetaminophen can nearly quadruple the risk of getting abnormal results on a liver function test; the lead author tells the CBC it's not clear whether that could lead to liver damage in the long term but that it is "a concern." Medical News Today noted last month that another large trial last year found similar results in terms of acetaminophen's usefulness in managing low back pain—and that a study this year found that doctors may be underestimating the risks of the drug, even at standard doses. (It's far from the first time acetaminophen has been questioned.)