Hi med students. Like the title says, I have a question about aspirin compared to NSAIDs such as ibuprofen and acetaminophen, specifically pertaining to influenza.
My question is why is Aspirin so much more harmful than taking ibuprofen or acetaminophen? I know Aspirin can cause Reye's syndrome but are their other reasons besides that? Aren't they all NSAIDS? <-- (that's what confusing me the most).
Thanks!
- A confused pre-med 😀
It's a loaded question, since there are several concepts that need to be addressed. First of all, ASA (Aspirin) and Ibuprofen (IBU) are both considered non-steroidal anti-inflammatory drugs (NSAIDs), while APAP (acetaminophen or Tylenol) is not. They both work by non-selectively blocking the cyclooxygenase (COX) pathway, thus inhibiting the production of prostaglandins, an class of factors that are inflammatory and pain mediators. This is how they reduce inflammation, pain, and fever. Both also block the formation of TXA2 (thromboxane A2) in your platelets, which prevents platelet aggregation and the formation of clots, and can increase the risk of upper GI symptoms (such as bleeds), since they also block the COX-1 pathway (you get the anti-inflammatory effects from the blocking of COX-2), which produces a prostaglandin involved in protecting the stomach. ASA happens to be a
non-competitive inhibitor of the COX pathway (a property that is taken advantage of for the effective blocking of platelet aggregation), so it carries a
much higher risk of upper GI symptoms and bleeding than IBU. Also, ASA is a salicylate, while IBU is not, which is a class of meds that some people can be sensitive or allergic to and have adverse reactions when taken (Steven's-Johnson syndrome, Reye's syndrome, ototoxicity, etc.). ASA toxicity is also notorious and well-documented. Aspirin can also cause or exacerbate respiratory symptoms in those who have triad asthma.
APAP has analgesic and anti-pyretic effects, but it is not a COX inhibitor and is not an NSAID. It has no significant anti-inflammatory effects. Consequently, it also does not carry the same risks or adverse effects. It can, however, be toxic to the liver when taken in excess. APAP is metabolized into a damaging free-radical by your body, when present in excess can cause harm to your liver and kidneys. Your body has an ability to handle free-radicals through the glutathione system. When you OD on APAP, you are exhausting that system, which you can replenish by giving N-acetyl-cysteine, the antidote for APAP overdose. Another point of trivia, which is may not be so trivial to your body, is that if you continually combine APAP with NSAIDS, it will lead to drug-induced damage to your kidneys and may lead to failure because of free-radical damage (from APAP) that is facilitated by diminished blood supply (NSAIDS).
Hope that begins to answer your question.
