What do painkillers like Advil and Ibuprofen do to your liver if you take too many of them and why?
In: Biology
In general, we don’t think of NSAID-class painkillers, such as ibuprofen (Advil), as a major trigger of liver damage. As has been mentioned by others, the much more prominent side effect of NSAIDs is kidney damage, because NSAIDs cause blood vessels in the kidney to clamp down, which reduces the flow of blood that feeds them. We worry about this especially in people who’ve been taking lots of NSAIDs for a long time, or in people who already have underlying kidney disease.
We think of acetaminophen/paracetamol (Tylenol) as the more liver-toxic medication, at least among OTC painkillers, and acetaminophen overdose is a classic cause for acute liver failure. In the worst case scenario, the only way death can be prevented in such patients is with emergency liver transplantation.
How can acetaminophen cause liver failure? One of the liver’s main jobs is to clear chemicals out of the blood. Many chemicals must be processed via multiple steps before the body can get rid of them. One important type of chemical processing requires adequate supply of a molecule called glutathione. Some of the intermediate states of even innocuous chemicals can be quite toxic. One intermediate breakdown product of acetaminophen is called NAPQI and is especially toxic to liver cells. When acetaminophen is overdosed, the liver becomes overwhelmed with NAPQI as it tries to process all that acetaminophen. This drains the liver’s glutathione supply, causing more NAPQI to build up, poisoning the liver cells, which causes even more NAPQI to accumulate… Badness ensues.
That said, acetaminophen is still quite safe, as long as it is consumed within dose limitations (up to a maximum of 4 grams in 24 hours for people with healthy livers), and we routinely give up to 2 grams per 24 hours even in patients who have just received liver transplantation. Livers are pretty resilient organs. Whether long-term acetaminophen use can cause lasting liver damage over time is less clear and an area of controversy, though I think it’s certainly a reasonable concern.
As for NSAID-induced liver injury – going back to your original question – it definitely does happen, but the ways it manifests are varied, and actual liver *failure* resulting from NSAIDs is extremely rare. We do sometimes see evidence of mild liver damage on blood tests in people who take NSAIDs, but the reasons for this are complicated and probably not the same from person to person. Certain kinds of NSAIDs (such as sulindac and diclofenac) are known to carry higher risk of liver damage, and certain types of underlying disease (such as rheumatoid arthritis) are associated with higher risk of liver damage in people taking NSAIDs. Drinking alcohol raises the risk of liver damage from pretty much any medication, NSAIDs included. The most common NSAIDs such as ibuprofen and naproxen are not known to be particularly liver-toxic on their own.
Aspirin is a unique case. It is known to cause a rare but severe combination of liver and brain damage called Reye syndrome, particularly in children who have recently been infected with the flu or chickenpox, which is why we avoid giving it to kids except in special circumstances. The reason why Reye syndrome occurs is not exactly known, and the most likely theories for the underlying cause are beyond the scope of this discussion.
**tl;dr: Most NSAID painkillers don’t do too much to your liver most of the time, but they can damage your kidneys. Tylenol does, however, damage your liver if overdosed. Don’t take more than what’s written on the bottle, don’t take more than your doctor says is OK, and don’t drink alcohol when taking either of these meds.**
Source: I’m an anesthesia resident physician in the US. We give patients lots of different kinds of pain meds.
Latest Answers