Why are anti-inflammatory tablets hard to stomach?

Anti-inflammatory drugs are widely used, and the ones that are readily available over the counter tend to be non-steroidal, such as aspirin and ibuprofen.

But if you find yourself in the position of needing to take these non-steroidal anti-inflammatory drugs (NSAIDs) for any length of time, you may know that they are hard on the stomach. Why is that?

At a biochemical level, it’s because they target enzymes that help to protect the stomach. NSAIDs block cyclo-oxygenases (Cox), a group of enzymes needed to make certain other biochemicals called prostaglandins.

This dampens down inflammation, because if Cox-2 doesn’t work, then the inflammatory prostaglandins don’t work.

But then in the 1980s and 1990s scientists homed in even closer and discovered that NSAIDs, such as aspirin, block not only Cox-2 but Cox-1 as well, and Cox-1 helps to make protective prostaglandins in the stomach. Hence the dodgy effects on the tummy if used frequently over time.

Newer generation anti-inflammatories were developed to target only Cox-2 and so squash down inflammation without hammering the stomach’s protection, but they were found to slightly increase risk of heart attack, so their use is now limited.

And interestingly, this tale involved Irish scientists – Luke O’Neill, now professor of biochemistry at Trinity – helped in the identification of the inflammatory Cox and its targeting by the NSAIDs, and Garret FitzGerald, professor of medicine at the University of Pennsylvania, flagged the problem of the increased risk of heart attack associated with newer, Cox-2 specific drugs.