What is the difference between aspirin, acetaminophen, ibuprofin and naxproxin?

They are the most common over the counter pain medications available. The last three are most commonly sold under the brand names Tylenol, Advil and Aleve respectively. (Excedrine is a mix of aspirin, aceteaminophen and caffeine.)

How do they work? Given how they work, what would be the best choice for a standard headache and what for sore muscles from, say, a workout?

Brief answer on which to choose:

Whatever works for you, frankly.

Aspirin, ibuprofen, and naproxen are all anti-inflammatory pain killers, and no one is superior to the other for pain relievers overall. And none of them reduce inflammation unless they are taken regularly for at least a week, usually more. So an individual should use whichever one seems to work best for them. It can cause GI upset, stomach erosions which may bleed, and may stress the kidneys in susceptible people.

Acetaminophen is a pain killer, but not an inflammation-fighter. It is equally effective as a pain reliever overall as the NSAIDS. Again, the individual should choose based what works for them. Excessive amounts, especially if used with alcohol, may damage the liver.

In addition to the good doctors advice above, I do not have an answer but a site to look up for data on drugs.

I found it pretty helpful when dealing with prescribed or over the counter medicines where the consumer sheets were absent or in a language I had no hope of understanding.

Search for a drug and look at the consumer or the profesional data
For ibuprofen see here

I’ve been told by my pharmacist that, since I’m taking mobic (an NSAID), I should only take acetaminophen if I need an extra boost against pain because of a headache. It’s in a different category and won’t be double-stressing either my liver or my stomach, I forget which.

The most significant difference to me, though, is that if I take ibuprofen while I have a headache, I’ll throw up. Haven’t met anyone else who does that, but it sort of sticks in my mind.

Yes, he is more or less correct. But here’s what I posted earlier in GQ:
"Acetaminophen (called “paracetamol” elsewhere). A does of as little as 2X the RDA can cause catastrophic liver damage, esp when combined with booze.

wiki:*Paracetamol is contained in many preparations (both over-the-counter and prescription-only medications). In some animals, for example cats, small doses are toxic. Because of the wide availability of paracetamol there is a large potential for overdose and toxicity.[19] Without timely treatment, overdose can lead to liver failure and death within days; paracetamol toxicity is, by far, the most common cause of acute liver failure in both the United States and the United Kingdom.[20][21] It is sometimes used in suicide attempts by those unaware of the prolonged timecourse and high morbidity (likelihood of significant illness) associated with paracetamol-induced toxicity in survivors…The toxic dose of paracetamol is highly variable. In adults, single doses above 10 grams or 150 mg/kg have a reasonable likelihood of causing toxicity.[22] Toxicity can also occur when multiple smaller doses within 24 hours exceeds these levels, or even with chronic ingestion of doses as low as 4 g/day, and death with as little as 6 g/day.

In children acute doses above 200 mg/kg could potentially cause toxicity. This higher threshold is largely due to children having larger kidneys and livers relative to body size than adults and hence being more tolerant of paracetamol overdose than adults.[23] Acute paracetamol overdose in children rarely causes illness or death with chronic supratherapeutic doses being the major cause of toxicity in children.

Since paracetamol is often included in combination with other drugs, it is important to include all sources of paracetamol when checking a person’s dose for toxicity. In addition to being sold by itself, paracetamol may be included in the formulations of various analgesics and cold/flu remedies as a way to increase the pain-relieving properties of the medication and sometimes in combination with opioids such as hydrocodone to deter people from using it recreationally or becoming addicted to the opioid substance, as at higher doses than intended the paracetamol will cause irreversible damage to the liver. In fact, the human toll of acetaminophen, in terms of both fatal overdoses and chronic liver toxicity to habitual abusers of pain medication, likely far exceeds the damage caused by the opioids themselves.[24][page # needed] To prevent overdoses, one should read medication labels carefully for the presence of paracetamol and check with a pharmacist before using over-the-counter medications.*
Americans, etc please read acetaminophen where it says paracetamol."

You forgot to Ask About The Purple Pill (great painreliever advice, Google!):rolleyes:

Are you saying here that any pain relief from, say, an Aspirin taken for a headache is a placebo effect? Or is it that they have more immediate pain relief effects over and above their anti-inflammatory effects?

AFAICT, he separating the pain relief from the anti-inflammatory properties

Yep. NSAIDS do both. They reduce pain with a single dose, and they reduce inflammation, but only if taken chronically.

Is there any difference in the way they work? I mean, how does pain medication work anyway - what part of the system do they work on? The brain? Nerves in parts of the body?

Which (if any) are effective in reducing fevers?

I don’t mean to challenge your credibility, but do you have a cite for this.

Qadgop the Mercotan

My orthopedist says that I should take before strenuous exercise to reduce swelling in my knee. He said to take as necessary, not regularly.

From the Micromedex proprietary site (Basically an online PDR) regarding Ibuprofen, a standard NSAID:

From the United Healthcare site: http://www.uhclatino.com/informationCenter/medicine.html

I apologize for not finding better cites, but most scholarly articles I reviewed were more about the difference between Cox-I and Cox-2 inhibitors.

I take naproxen for arthitus, and my Doc said exactly what Qadgop the Mercotan has said. The anti-inflamitory process takes a while to kick in, and my Doc said I should take it twice a day, every day.

And, my Doctor is an expert on Arthritus, and has treated me for well over a decade, so he both knows his stuff and me as his patient.

Of course, your body may react a bit differently.

So what you are saying is “Booze, no. Chronic, yes?” If I do that in Wisconsin, won’t it increase the chances we’ll finally meet?

After your Pit thread I couldn’t resist.

Thanks for the answers. I am definately going to chat up my Dr.

That’s very interesting about the anti-inflammatory properties. I would wager that most docs don’t know that. I’ve regularly received the same advice as WorkInProgress, especially when it comes to reducing swelling associated with sports injuries. I’ve always used ibuprofen in combination with other swelling-reducers (elevation, ice, rest, etc.), so I’ve never noticed that it doesn’t have an effect.

Is it your experience, QtM, that the medical world hasn’t quite caught onto that? Or have WIP and I just had idiosyncratic experiences?

They work by blocking enzymes called cyclooxygenases (COX). These enzymes catalyze the rate-limiting step in the synthesis of hormones of the prostaglandin and thromboxane family. These hormones play a role in pain signalling, inflammation and platelet aggregation. Article

Different NSAIDs differ by their relative activity on two isoforms of the enzymes, and by the type of inactivation: Aspirin reacts with the active site of the enzymes and blocks it irreversibly, Ibuprofen gives a reversible competitive inhibition, some NSAIDs preferentially block the COX-2 isoform of the enzyme.

In my experience anaprox has provided very fast relief. Much faster than a few days. And it provided more relief than any other OTC meds.
I had previously assume it was because of it’s anti-inflammatory properties.

Anaprox actually is the same as OTC Aleve, in terms of the active ingredient. Both are Naproxen Sodium. The primary difference is that typical doses of the Anaprox are higher than the OTC dose (550mg Rx vs 220mg OTC)