How does Advil, aspirin, etc, treat different aches like headaches, backaches, sore feet, etc? I know most of them have caffeine to speed up blood flow, but how does it seem to cure everything?
In: Chemistry
Aspirin and the related compound ibuprophen which makes up Advil both reduce inflammation. That is a general bodily response to injuries and overuse so it helps anywhere that the body tissues are stressed.
They don’t.
And most countries advertising standards agencies have sued them because of it. In Australia at least they can’t claim that.
Most OTC painkillers don’t contain caffeine. Advil and plain aspirin don’t. Most OTC painkillers (ibuprofen, aspirin, naproxen) are called non-steroidal anti inflammatory drugs or NSAIDs. Acetaminophen (paracetamol) is not an NSAID, but it blocks the pain of inflammation. Many common pains are associated with inflammation. NSAIDs help reduce inflammation. Some like Excedrin, Goodys, and Anacin are combined with caffeine which helps them work.
Advil and Aspirin are drugs in a class called Non-Steroidal Anti-inflammatory Drugs (NSAIDs), which all work by inhibiting an enzyme called Cyclooxygenase (COX). COX is responsible for [converting Arachidonic Acid into various Prostaglandins](https://www.frca.co.uk/images_main/Pain%20resource/PGsynthesis.png). The Prostaglandins are an important component of the body’s inflammatory response. They can cause there to be increased blood flow and recruiting of white blood cells to an injured area. Prostaglandins also play a role in the complex system which determines how one experiences pain with their presence increasing pain perception. With the NSAIDs blocking the production of Prostaglandins, we can decrease inflammation in the body, and decrease the perception of pain.
Prostaglandins also have other effects on many other systems in the body. They increase blood flow to the kidneys, which is why using NSAIDs (which block Prostaglandin production and thus decrease blood flow to the kidney) in patients with kidney failure is not typically recommended. Prostaglandins are protective for the GI tract and help to maintain the lining of the stomach, which is why using NSAIDs chronically can cause stomach ulcers. Prostaglandins also play a role in the way that our blood is able to clot. A Prostaglandin derivative, Thromboxane A2 helps our platelets adhere to each other to form a ‘plug’ in the cut, so we can stop t he bleeding.
In reality, the inflammatory system is more complicated than is presented, as some Prostaglandins are pro-inflammatory, and some are anti-inflammatory and the complex balance between these two systems is what determines what occurs physiologically.
Some pills such as Excederin migraine do have caffeine as a component of the pill, however, that is a completely different mechanism of action, and not required for the function of NSAIDs.
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