There are many common medical practices that have surprisingly little evidence to back them up. It turns out, taking acetaminophen (brand name Tylenol) for low back pain is one of them.
A first-of-its-kind, large-scale study published today in The Lancet looked at whether acetaminophen performs better than placebo to help patients with low back pain. The results were not reassuring. While low back pain is the leading cause of disability worldwide, and many people rely on first-line painkillers like Tylenol, it turns out they can be useless.
As the lead study author, Dr. Christopher Williams, summed up: "Our results—based on over 1,600 patients—provide clear evidence that acetaminophen is ineffective for low back pain."
Acetaminophen didn't help with episodes of low back pain at any time during the three-month study, and it worked no better than placebo to speed up recovery. Since there were no large-scale studies looking at the impact of the painkiller on low back pain before this Lancet article, it may be a game-changer. Here's how to think about it at the personal and policy level.
What patients should do with this new information
Dr. Williams, a clinician-researcher in New South Wales, Australia, said that if people with low back pain haven't started treatment and are trying to decide what to do next, the new study shows that acetaminophen won't help them recover quicker or dull their pain. "So there is no justification to recommend it to them."
For those who may already be using acetaminophen, Dr. Williams said they should continue if they feel it's helping. But, "If patients don't improve after one or two weeks despite trying to maintain normal activity and avoiding bed rest, they should return to their clinician for a review."
At that point, the doctor or pharmacist might suggest another medication. There is also some evidence that applying heat or spinal manipulation may help, too.
Dr. Williams warned that most of the patients in the trial were not experiencing severe low back pain—such as the kind that could cause one to miss work—so the results of the trial may not be applicable to them.
How doctors should think about the study
Doctors may consider downgrading the role of pain-relief medications in helping patients manage their low-back pain, Dr. Williams said. "Instead the emphasis of treatment should be on reassurance and advice to remain active."
How the study could change medical guidelines
As it stands, clinical guidelines from American medical groups near universally recommend doctors give patients with low-back pain first-line painkillers like acetaminophen. So the study authors suggest those guidelines be reconsidered if more studies like theirs confirm the results.
"In our study, 50 percent of participants completely recovered in just over two weeks, despite no effect of the acetaminophen," said Dr. Williams. "This is much faster than other studies suggest and points to the need for patients to be encouraged to stay active, avoid bed rest and to be reassured that they are likely to have a favorable recovery."
While some guidelines do recommended this, he added, "We know from research that patients often miss out on this aspect of care. And it may be that this is the most important part of helping patients with low back pain. So, we think future studies and guidelines could focus on how best to communicate these key messages to patients."