Study Casts Doubt on Acetaminophen for Low Back Pain, Arthritis

Acetaminophen – best know as Tylenol in the United States – does not appear to help ease lower back pain and offers little relief for the most common form of arthritis, according to a new report.

The review of data from 13 studies could challenge existing recommendations on pain relief, experts say.

“These results support the reconsideration of recommendations to use [acetaminophen] for patients’ with these conditions," concluded a team led by Gustavo Machado of The George Institute for Global Health at the University of Sydney in Australia.

The researchers analyzed 10 studies that examined the use of acetaminophen to treat osteoarthritis of the hip or knee, and three studies that assessed the use of the painkiller for lower back pain.

Osteoarthritis – the most common form of arthritis – and back pain are among the leading causes of disability worldwide, the researchers said. Current clinical guidelines recommend acetaminophen as the first-line drug treatment for both conditions.

However, doubts about the effectiveness of the drug in treating the conditions, and concerns about the safety of the recommended full dose (up to 4,000 milligrams a day), have made those guidelines controversial, Machado’s team said.
Looking at the pooled data, the investigators found that for people with lower back pain, acetaminophen was ineffective in either reducing patient disability or enhancing quality of life.



In people with osteoarthritis of the hip or knee, acetaminophen provided only a small, not clinically important benefit in the reduction of pain and disability, the study found.

The findings were published March 31 in the journal BMJ.

McNeil Consumer Healthcare, the maker of Tylenol, countered that acetaminophen has a long history effectiveness. In a statement, the company said that before clinical guidelines are changed. “It is important to comprehensively look at the body of evidence…The safety and efficacy profile of acetaminophen is supported by more than 150 studies over the past 50 years.

My Take:
Tylenol is an interesting drug. We don’t fully understand in method of action like the Cox 2 inhibitors – aspirin, Aleve, and Advil. However, in the nervous system it does act like a Cox 2 inhibitor by blocking prostaglandins.

Despite all the emphasis on “evident based medicine”, we don’t know how most drugs work on the body. Research is geared toward reducing symptoms rather than really understanding how a particular drug alters body chemistry. This is why so many drugs have side effects very similar to the symptoms they are designed to treat. The drug alters the chemical pathways in some unknown fashion changing symptoms.

Tylenol is very toxic to the liver and is responsible for thousands of deaths each year in the United States. My clinical experience is that it provides very temporary relief at best and is most often ineffective in the treatment of musculoskeletal pain and inflammation.

The Bottom Line:
Throw that Tylenol away, but don’t flush it down the toilet. We don’t want it in our drinking water.

Source: April 1, 2015 National Institutes of Health