Pain

CAUSES OF PAIN
Injuries cause the release of prostaglandins and therefore cause pain. Prostaglandins are potent vasodilators and pro-inflammatory compounds that cause the erythema (redness), pain, and hyperemia (increased blood flow) associated with trauma or oral tissue damage.
The enzyme cyclooxygenase converts arachidonic acid to prostaglandins and thromboxanes.
Prostaglandin-synthesis inhibitors (PSI) include acetaminophen (Tylenol), ibuprofen (Motrin), and aspirin. PSI’s reduce
pain because they interfere with the function of the enzyme cyclooxygenase.

A SideBar on Sensitivity to Pain
http://www.newscientist.com/news/news.jsp?id=ns99993423

A tiny variation in a single gene which makes a protein important for brain chemistry, catechol-O-methyl transferase (COMT), an enzyme vital for mopping up the dopamine brain chemical linked with sensing pain. Jon-Kar Zubieta and his team at the University of Michigan and The National Institute of Alcohol and Alcoholism, Rocksville, Maryland show that the COMT gene exists in two forms which make copies differing by a single amino acid only - either valine or methionine. This small variation has a big effect on the activity of COMT. People with the laziest form of the gene - who have two copies of the methionine version - make enzymes three- to four-fold less effective than the other variants contained just valine or one of each. People with the active form of COMT were hardier, whereas people the less active version feel pain more acutely. Those with both forms of the gene, one from each parent, experience intermediate pain.

NSAIDs (Non Steroidal Anti-Inflammatory Drugs)
The most common of these are Aspirin, Ibuprofen, Acetemenophen (Tylenol), and Naproxen

Ibuprofen cross-effects:
http://www.gnc.com/health_notes/Drug/Ibuprofen.htm
Note especially that Copper supplementation appears to increase the effectiveness of NSAIDs and aspirin.
Iron supplementation may be appropriate, to counter Iron loss from Ibup. (and aspirin) use.
The flavonoids found in the extract of licorice known as DGL (deglycyrrhizinated licorice) are helpful for avoiding the irritating actions NSAIDs and aspirin have on the stomach and intestines.
http://www.hollandandbarrett.com/Drug/NSAIDs.htm

"Although aspirin reduces swelling, pain, and fever just like NSAIDs, it is classed (by some) as a member of the salicylate family of drugs."
http://www.hollandandbarrett.com/Drug/Aspirin.htm
Supplements which may be indicated with aspirin include Folic Acid, Vitamin C, and Zinc (see also note on Copper, above). Vitamin E may increase bleeding in conjunction with Aspirin, but that is not well demonstrated. (Folic Acid excretion in urine is seen in rheumatoid arthritis patients, even without Aspirin intake, so supplementation at 4oomg is indicated.)

Aspirin/Ibuprofen/Tylenol effects and uses; Aspirin chemistry
http://www.bhc.edu/EastCampus/Abbott/CH110%5CC10Reva.htm

More info on NSAIDS and Salicylates - Side effects and cross effects
http://lib-sh.lsumc.edu/fammed/intern/nsaids95.html

Anti Cancer effects - The nonsteroidal anti-inflammatory drugs aspirin and indomethacin attenuate -catenin/TCF-4 signaling
Increasing epidemiological and experimental evidence implicates non-steroidal anti-inflammatory drugs (NSAIDs) as anti-tumorigenic agents. The precise mechanisms whereby NSAIDs exert their anti-neoplastic effects remain poorly understood. Studies from hereditary and sporadic colorectal cancer (CRC) patients suggest that NSAIDs may interfere with initiating steps of carcinogenesis
http://www.nature.com/cgi-taf/DynaPage.taf?file=/onc/journal/v20/n5/full/1204123a.html

Enough Ibuprofen at the wrong time may block aspirin's ability to protect against heart attacks
Ibuprofen and other Cox-1 (cyclooxygenase) inhibiting NSAIDs may block aspirin's effects on platelet activity, which is the source of aspirin's heart/circulatory benefit. The mechanism is through binding by the NSAID to the COX-1 enzyme, preempting the ability of aspirin to do so. However, taking the aspirin two hours before the ibuprofen permits the aspirin to preempt the binding, and so preserve the effectiveness of the aspirin regime in protecting the heart. Unfortunately, repeated (3 or more a day) use of a COX-1 NSAID such as Ibuprofen has been shown to leave enough of the drug in the system to prevent the aspirin binding. (Link)
http://216.239.53.100/search?q=cache:Ddf3RdqXA5sC:www.pain.com/news/news.cfm+aspirin+ibuprofen+together&hl=en&ie=UTF-8
http://www.applesforhealth.com/MensHealth/ibuph3.html

(Result = Take no more than 2 NSAID (Ibuprofen) a day; start with the "heart" aspirin, take the first Ibuprofen at least 2 hours after the first aspirin; take the second 6-8 hours after the first. For the "usual" third dose of Ibuprofen pain relief, substitute an aspirin (or two) 6-8 hours after the second Ibuprofen,

Common Painkiller Cuts Heart Benefits of Aspirin
http://www.reuters.com/newsArticle.jhtml?type=healthNews&storyID=2231180
"When patients taking aspirin for cardioprotection require chronic treatment of inflammation with an NSAID, the addition of diclofenac or a conventional selective COX-2 inhibitor would seem preferable to ibuprofen,"

Ibuprofen belongs to a class of drugs known as non-steroidal anti-inflammatory drugs (NSAIDs). They relieve pain by blocking the action of an enzyme called Cox-1, which is found in the stomach and the blood, and Cox-2, which is in the skin and joints and is also produced at the site of a wound or pain.

COX-2 Inhibiting (COX-1 sparing) NSAIDs
http://www.thedrugmonitor.com/coxi.html
http://arthritis.about.com/cs/cox/

GENERIC = BRAND PAIRINGS for COX-2 Inhibitors
celecoxib = Celebrex (Rheumatoid and Osteoarthritis) <se kidney damage, gastrointestinal ulceration>
Rofecoxib = Vioxx (Osteoarthritis) <se liver damage? heart?> [Rofecoxib studies in OA patients showed no differences with
Diclofenac and Ibuprofen as far as efficacy, less adverse events and less withdrawal rates]
diclofenac = <se gastrointestinal ulceration>
valdecoxib = Bextra (Lupus) <se skin diseases Stevens-Johnson syndrome, toxic epidermal necrolysis and exfoliative dermatitis>

Experimental evidence has shown that COX-2 promotes survival of colonic adenomas and colonic cancer as well as its expression is associated with the deposition of beta-amyloid protein in Alzheimer's disease; COX-2 inhibitors may find utility in the prevention or treatment of these conditions but human studies have to corroborate the in vitro and in vivo findings

Other drugs side effect information:
acetaminophen = Tylenol <se liver damage>
aspirin = var. <se gastrointestinal bleeding>
naproxen = <se gastrointestinal ulceration> <Vioxx users had half the rate of ulcers and bowel perforations as those taking naproxen>