COX-2 specific NSAIDs (Celebrex)
In general, NSAIDs prevent inflammation by inhibiting cyclooxygenase (COX) enzymes that promote the production of prostaglandins, thromboxanes, and prostacyclin. These are all inflammatory mediators.1 Two types of COX enzymes exist; COX-1 are responsible for maintenance and protection of the gastrointestinal tract, and COX-2 are responsible for inflammation and pain. NSAIDS in general affect prostaglandin synthesis non-selectively, ie, COX 1 and COX 2 enzymes are inhibited. As a result, NSAIDs have a side effect of producing GI ulceration and potentially intestinal bleeding. Use of NSAIDs is contraindicated in patients with a history of ulcers or those on blood thinners.
Celebrex is A NSAID that specifically targets and inhibits the action of COX 2 specifically, the cyclooxygenase enzyme that causes inflammation. It does not affect the GI tract. This specificity allows it to function as an anti-inflammatory agent without reducing the protective effects prostaglandins on the GI tract.
In a review of the literature, Laine et al found that COX-2 inhibitors are more effective in treating knee OA than Tylenol, and equally as effective as traditional NSAIDs. They also found that COX-2’s cause fewer GI problems than traditional NSAIDs, however they have an increased risk of cardiovascular issues vs. placebo or naproxen.5
In a study by Ding et al researchers used MRI to study cartilage volume and cartilage defects in older patients with knee osteoarthritis. The study was performed after three years of the patients using traditional NSAIDs, COX-2 inhibitors, or not using drugs at all. They found that those who used COX-2 inhibitors vs. traditional NSAIDs had decreased loss of cartilage volume, and decreased progression of cartilage defects. The COX-2 inhibitors were more effective at slowing the progression of osteoarthritis.4
In a Celebrex sponsored study evaluating its effectiveness in treating osteoarthritis researchers found Celebrex to be superior to placebo at reducing pain. Controlled clinical trials evaluated Celebrex for treatment of hip and knee OA over a 12 week period. They found that a dosage of 200 mg daily helped improve patient’s Western Ontario and McMaster Universities (WOMAC) score, which evaluates pain, stiffness, and functionality. Researchers found this dosage to be as effective as 1000 mg of naproxen daily.
In a report by Jenkins and Seligman, Vioxx was found to decrease the chance of severe GI bleeding, however it was found to cause serious adverse cardiovascular effects compared to a placebo in a long-term controlled clinical trial. In 2004, Vioxx was taken off the market. Likewise in 2005, Bextra was taken off the market leaving Celebrex as the only Cox-2 currently available (Jenkins JK, Seligman PJ. Memorandum, April 6, 2005).
Therefore, one should attempt to use the lowest dose of medication for the shortest amount of time possible. Patients with a history of cardiovascular disease should have approval from their cardiologist prior to taking Celebrex.1