The popular over-the-counter painkiller Tylenol is no more effective as a placebo in treating back pain, knee or hip pain, or arthritis, according to a systematic review of randomized clinical trials.
Tylenol contains the active drug ingredient acetaminophen, which is also available in various OTC brands as well as in greater doses and/or in combination with other drug ingredients in many prescription medications.
The review, conducted by Australian researchers, involved three randomized trials that pitted the effects of acetaminophen against a placebo for spinal pain, and 10 trials evaluating the drug for relieving the pain of osteoarthritis. In total, the analysis involved 5,366 patients. Dosages ranged from 3,000 to 4,000 milligrams per patient per day, except for one study, which involved a dose of 1,000 milligrams delivered intravenously.
Researchers found that Tylenol was essentially ineffective at treating low back pain and/or disability. Patients who used Tylenol to treat knee or hip arthritis found small yet clinically insignificant relief for short-term pain. Even more concerning is that the drug quadruples the risk of abnormal liver function.
Researchers and doctors have known for years that acetaminophen can damage the liver. Too much of the drug or combining the drug with alcohol can have deadly consequences. As a result, the Food and Drug Administration (FDA) has ordered that manufacturers of acetaminophen-containing drugs to limit doses to 325 milligrams or less, and added a black box warning to the safety labels of these drugs.
Last year, in an effort to enfoce these requirements, the FDA revoked approval of seven narcotic painkillers containing acetaminophen, including Vicodin, which combines acetaminophen with hydrocodone.