Over-the-Counter Pain Relievers Work to Prevent ALS, Study Suggests

Use of over-the-counter pain relievers, including acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen, significantly reduced the likelihood of developing amyotrophic lateral sclerosis (ALS), likely by working against inflammatory processes, a small meta-analysis reported.

Aspirin, however, was not seen to affect disease incidence.

The study, “The effectiveness of nonsteroidal anti-inflammatory drugs and acetaminophen in reduce the risk of amyotrophic lateral sclerosis? A meta-analysis,” was published in Scientific Reports.

Inflammation in the brain is a hallmark feature of ALS, contributing to the death of nerve cells and symptom progression.

Evidence suggests that the COX enzymes are key players in most inflammatory processes, including those of ALS. Because NSAIDs block the activity of these enzymes, researchers have suggested they might help to prevent ALS or limit its progression.

NSAIDs include most of the widely used over-the-counter pain relievers, such as aspirin, acetaminophen (sold as Tylenol among many other brand names), ibuprofen (sold as Motrin and Advil, among many others) and naproxen (brand names include Aleve and Naprosyn, among others).

Acetaminophen is not considered an NSAID, but it also inhibits COX activity.

Three studies conducted to date have examined the association between the use of these medications and ALS incidence, but produced inconsistent results.

Researchers in South Korea did a meta-analysis — an approach that combines the results of multiple scientific studies to increase the pool of data, allowing for a more comprehensive review — of these three studies to try for greater clarity.

In total, this analysis covered 794,622 study participants, including 1,548 ALS patients and 793,114 people without this disease who served as controls.

These researchers investigated whether the use of acetaminophen, aspirin, and NSAIDs other than aspirin significantly differed between patients and controls.

They found a significant difference in the use of acetaminophen and non-aspirin NSAIDs, but not in aspirin use. In fact, the likelihood of developing ALS was 20% lower among people who used acetaminophen compared with those who didn’t. Disease odds were 18% lower among people using non-aspirin NSAIDs compared with non-users.

“We found that the use of NA-NSAIDs and acetaminophen is associated with a decreased risk of development of ALS, and these medications seem to confer neuroprotective effects,” the researchers wrote.

“Non-aspirin NSAIDs inhibit the activity of COX-2, consequently inhibiting the inflammatory process … This explains why non-aspirin NSAIDs would confer neuroprotective effects which seem to suppress the development of ALS,” they added.

A number of limitations apply to these findings, the team wrote, because of the small pool of data available for the meta-analysis (three studies), a lack of control for confounding factors, and a lack of specific information on types and doses of NSAIDs used.

Additional and high-quality studies are needed to confirm the effectiveness of non-aspirin NSAIDs and acetaminophen against the risk of ALS occurrence, the researchers concluded, and possibly to confirm findings with aspirin.