For some of us, popping an aspirin is as common as brushing our teeth. But what are we really doing to our bodies when we treat an ache or a pain with some ibuprofen or break out the ice pack?
I've learned a lot about inflammation in the last few months since I joined the Immunology Department as a postdoc. In addition, our lab studies the connection between inflammation and atherosclerosis (accumulation of plaques in the arteries). Contrary to traditional belief, atherosclerosis is more than just a metabolic disease. It is also a chronic inflammatory disease, similar to arthritis or asthma. But I digress...
First off, what are NSAIDs? They are non-steroidal anti-inflammatory drugs, including aspirin (salicylate), Ibuprofen (Motrin, Advil, etc.), acetaminophen (Tylenol), and COX-2 specific inhibitors, such as Vioxx or Celebrex. Although they all act on the same pathway, each drug has slightly different effects for unclear reasons.
Efficacy of Different NSAIDs:
For instance, in addition to pain-relieving, anti-inflammatory properties, aspirin is also the most potent at preventing clotting, which is why patients are advised not to take it before a surgery. In addition, people suffering from symptoms of a heart attack have been advised to take an aspiring while waiting for the ambulance. The reasoning behind this suggestion is that if the heart attack is being induced by a clot, the aspirin will thin the blood and potentially break up the clot. Acetaminophen is least effective in anti-inflammatory properties but is still effective as an anti-pyrogenic (preventing fever). In addition, acetaminophin is renowned for being gentle on the tummy. Ibuprofen is typically most effective in relieving aches and pains associated with soft tissue injuries and joint pain (overuse injuries from training).
How do NSAIDs work?
Invariably, all these drugs block pain by inhibiting the enzyme COX-2 (cyclooxygenase-2). This enzyme converts arachidonic acid (a type of fatty acid) into prostaglandins. There are several different types of prostaglandins, all of which have important functions in various pathways, such as stimulating cell growth, inhibiting cell death, stimulating the growth of new blood vessels (angiogenesis), recruitment of platelets (clotting), pain, swelling, and inflammation. Because COX-2 is involved in tissue repair and wound healing, studies have been done to investigate whether inhibition of COX-2 activity with NSAIDs might delay healing.
Sidenote--NSAIDs and fever:
"For the most common disorders associated with fever, however, there's no convincing evidence that fever itself hastens recovery from common infections or that it correlates with a better outcome. There's experimental evidence that higher temperatures are harmful to certain bacteria, but medical experts disagree about whether this translates into a role for fever improving our ability to fight infection. In fact, most experts do agree that suppressing fever (for example, with acetaminophen) is not harmful, may be helpful, and they would never suggest trying to raise body temperature when fever is present...Since higher body temperature doesn't contribute to recovery, efforts to raise body temperature during a fever aren't advisable and may even be dangerous. And while one's appetite may be poor when a fever accompanies illness, there's no clear benefit (and there may be harm) to the strategy of trying to "starve a fever.""
Sidenote--Side-effects NSAIDs (COX-1):
NSAIDs and Muscle Injuries:
In addition, if you have chronic inflammatory condition, like arthritis or tendonitis, the use of NSAIDs may actually be beneficial. In this instance, your body's immune system has tried (and failed; hey, we're not perfect!) to heal the injury but is now in a vicious, futile cycle of a chronic inflammatory state, which can actually weaken your body overall. The immune system can't be as good as a sentinel at warding off infection when its investing so much energy in inflammation for a chronic injury that's never going to heal.
Along similar lines, use of ice to reduce inflammation directly over the injured area, is also an effective measure of minimizing pain, reducing inflammation, and perhaps preventing onset of muscle trauma, soreness, and injury. Many Olympic and pro athletes, such as Olympic marathoners, Paula Radcliffe and Deena Kastor, swear by "ice baths" and actually lower their entire body into a literal bath of ice after a hard workout. Now that's hard-core! Cold reduces swelling and initially restricts blood flow, providing a natural compress on the microscopic tears in the tissue that are leaking blood into the traumatized area. Shortly, the body will recruit new blood to the cold area that flushes out metabolic wastes and lactic acid - byproducts of heavy muscle activity.
Other informative websites on NSAIDs:
Common Exercise Myths
OTC Pain Medication (Univ of Chicago)
NSAIDs and Musculoskeletal Treatment
NSAIDs and sports injury (Physioroom)
Ice Therapy websites:
Ice in Your Bath (Squashsite)
Research articles (NSAIDs and Treatment Injured Muscle):
1. Vignaud A, Cebrian J, Martelly I, Caruelle JP. Effect of anti-inflammatory and antioxidant drugs on the long-term repair of severely injured mouse skeletal muscle. 2005. Exp Physiol. 90(4):487-495.
2. Baldwin Lanier A. Use of nonsteroidal anti-inflammatory drugs following exercise-induced muscle injury. 2003. Sports Med. 33(3):177-185.
3. Dudley GA, Czerkawski J, Meinrod A, Gillis G, Baldwin A, Scarpone M. Efficacy of naproxen sodium for exercise-induced dysfunction muscle injury and soreness. 1997. Clin J Sports Med. 7(1):3-10.