New research suggests the popular analgesic acetaminophen shows no effect on low-back pain and offers mixed results in managing osteoarthritis (OA) pain. According to a study published in The BMJ (March 2015), the benefit of acetaminophen (Tylenol) for reducing low-back pain intensity is only -0.5 points on a scale of 0 (pain-free) to 100 (worst pain). When looking at reducing pain intensity in hip or knee OA, acetaminophen fared somewhat better (-3.7 points), but the change was still not clinically significant. The studys results differ from earlier meta-analyses, which demonstrated a clinically significant reduction in pain for hip or knee OA treated with acetaminophen. The drug is considered safe in doses up to 4,000 mg per day, but the current study found that patients taking acetaminophen are four times as likely to have abnormal liver tests. Currently, the manufacturer and many experts have lowered the maximum recommended dose to 3,000 mg daily.