Acetaminophen’s Clinical Guidelines Don’t Match Study Results
A study recently published in The BMJ has determined that acetaminophen does not do much to provide relief from osteoarthritis pain and low back pain. Some clinical guidelines have recommended using acetaminophen as a first-line therapy.
The Australian research team, which included a pharmacist, analyzed data from 13 randomized, placebo-controlled, clinical trials of acetaminophen in patients suffering from chronic spinal pain or chronic osteoarthritis of the knee or hip.
The analysis showed acetaminophen was not effective for treating low back pain and offered minimal short-term benefits that were not clinically meaningful in osteoarthritis patients. As a result of this study, the research team recommends that pain management guidelines which recommend acetaminophen as the first therapy to treat these conditions need to be reevaluated.
Though the study somewhat confirms what is seen in clinical practice, it’s not necessarily time to count acetaminophen out. Mary Lynn McPherson, who is a professor and vice chair for pharmacy practice and science at the University of Maryland School of Pharmacy in Baltimore, specializes in pain management at the University of Maryland Primary Care at Heritage Crossing. The majority of her patients suffer from osteoarthritis, fibromyalgia, and low back pain.
McPherson says that by the time most of her patients get to her, it has gone beyond using acetaminophen for treatment. She says that if a medical professional wants to recommend using acetaminophen for the treatment of low back pain or osteoarthritis, it should be done when the patient has no risk factors for liver damage. She says a high dose of up to 4 g per day is probably needed before a decent trial of the drug’s effectiveness can be evaluated. Because of the risk with acetaminophen for liver damage, patients at risk for liver damage cannot safely and effectively use the higher dosage.
According to the FDA, adults should take no more than 4 g of acetaminophen every day, but the nonprescription labeling typically recommends no more than 3 g per day for adults.
Some patients may use acetaminophen as a minor part of a more comprehensive regimen that includes other medications and draw nondrug interventions. Most chronic pain can be benefited through lifestyle modifications, including exercise and weight loss. It is difficult to motivate patients to lose weight and exercise, particularly if they are poor, don’t have transportation, and cannot afford a gym membership.
As such, patients are incredibly frustrated. Overweight patients who have osteoarthritis of the knee are often told to go walk, but every time they go walk, they feel tremendous pain. It’s best to encourage patients to do with they can, opting for seated exercises as well as other activities that don’t aggravate the pain.
Acetaminophen can be used with other drugs and treatments to improve function and quality of life, but expecting it to do the job on its own isn’t realistic.