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Celecoxib is a non-steroidal anti-inflammatory drug (NSAID) used in the
treatment of osteoarthritis, rheumatoid arthritis, acute pain, painful
menstruation and menstrual symptoms, and to reduce numbers of colon and rectum
growths polyps in patients with familial adenomatous polyposis. It is marketed
by Pfizer under the brand name Celebrex.
Pharmacology
Celecoxib is a highly selective COX-2 inhibitor and primarily inhibits this
isoform of cyclooxygenase, whereas traditional NSAIDs inhibit both COX-1 and
COX-2. Celecoxib is approximately 10-20 times more selective for COX-2
inhibition over COX-1. In theory, this specificity allows celecoxib and other
COX-2 inhibitors to reduce inflammation (and pain) while minimizing
gastrointestinal adverse drug reactions (e.g. stomach ulcers) that are common
with non-selective NSAIDs. It also means that it has a reduced effect on
platelet aggregation compared to traditional NSAIDs.
Adverse effects
Aside from the incidence of gastric ulceration, celecoxib exhibits a similar
adverse drug reaction (ADR) profile to other NSAIDs.
Gastrointestinal ADRs
In theory the COX-2 selectivity should result in a significantly lower incidence
of gastrointestinal ulceration than traditional NSAIDs. The main body of
evidence touted to support this theory were the preliminary (6 month) results of
the Celecoxib Long-term Arthritis Safety Study (CLASS) as published in 2000,
which demonstrated a significant reduction in the incidence of gastrointestinal
ulceration in those taking celecoxib versus ibuprofen or diclofenac.
(Silverstein et al, 2000) The final (12 month) results from the CLASS study,
however, did not indicate any advantage of celecoxib over the other NSAIDs in
the study. (Malhotra, Shafiq & Pandhi, 2004)
Cardiovascular risk
The withdrawal of rofecoxib from the market in 2004 due to an increased risk of
adverse cardiovascular events led to the suspicion that this was a class effect.
Indeed an increased risk of heart attack and stroke was found in a National
Cancer Institute study studying the use of 400-800 mg celecoxib daily for the
prevention of colorectal adenoma (relative risk 2.3-3.4 vs placebo). (Solomon et
al., 2005)
There is still much conjecture, however, as to whether this risk is significant
for the majority of patients being treated with lower doses for osteoarthritis.
Allergy
Celecoxib contains a sulfonamide moiety and may cause allergic reactions in
those allergic to other sulfonamide-containing drugs. This is in addition to the
contraindication in patients with severe allergies to other NSAIDs.
Commercial history
Celecoxib was developed by G. D. Searle & Company and marketed jointly by Searle
and Pfizer under the brand name Celebrex. Searle was acquired by Pharmacia,
which was then acquired by Pfizer, in part so that Pfizer could take full
control of Celebrex.
Celecoxib is available by prescription in capsule form.
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