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
Main article: Non-steroidal anti-inflammatory drug
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.
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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.
