New Arthritis Drug - Celebrex
Celebrex is a new medication for the treatment of the
inflammation and pain of the two most common forms of
arthritis, rheumatoid arthritis and osteoarthritis. Celebrex is classified as a nonsteroidal anti-inflammatory
drug (NSAID), however, it is unique in its biologic action compared
to previously available drugs of this class.
This article will describe the action of nonsteroidal
anti-inflammatory drugs and some of the unique properties
of Celebrex. It will then conclude with an in-depth
interview of the chief scientist involved in the
development and testing of Celebrex.
BACKGROUND
What are NSAIDs?
Nonsteroidal anti-inflammatory drugs (NSAIDs) are
commonly prescribed medications for the inflammation of
arthritis and other body tissues, such as in tendonitis and
bursitis. Examples of NSAIDs include Aspirin, indomethacin (Indocin), ibuprofen
(Motrin), naproxen (Naprosyn),
piroxicam (Feldene), and nabumetone (Relafen). The major
side effects of NSAIDs are related to the gastrointestinal
system. Some 10%-50% of patients are unable to tolerate
NSAID treatment because of side effects, including
abdominal pain, diarrhea, bloating, heartburn, and upset
stomach (dyspepsia). Approximately 15% of patients on long-
term NSAID treatment develop ulceration of the stomach and
duodenum. Even though many of these patients with ulcers do
not have symptoms and are unaware of their ulcers, they are
at risk of developing serious ulcer complications such as
bleeding or perforation of the stomach.
NSAIDs are taken regularly by approximately 33 million
Americans!
The annual risk of serious complications is 1%-4% with
chronic NSAID treatment. The risk of complications is
higher in elderly patients, rheumatoid
arthritis sufferers, patients taking blood thinning medications
(anticoagulants such as Coumadin and heparin) or prednisone
(cortisone medication), and patients with heart disease or
a prior history of bleeding ulcers.
How do NSAIDs cause stomach ulcers and bleeding?
Prostaglandins are natural chemicals which are involved
in body inflammation. By inhibiting the body's production
of certain chemical messengers (prostaglandins), NSAIDs
decrease inflammation. However, certain prostaglandins are
also important in protecting the stomach lining from the
corrosive effects of stomach acid as well as maintaining
the natural, healthy condition of the stomach lining. By
disrupting the production of prostaglandins in the stomach,
NSAIDs can cause ulcers and bleeding.
What is the basic difference between traditional
NSAIDs and the newly designed COX-2 inhibitors?
Cyclooxygenase-1 (COX-1) is an enzyme which is normally
present in a variety of areas of the body, including sites
of inflammation and the stomach. The COX-1 enzyme of the
stomach produces certain chemical messengers (called
prostaglandins) that ensure the natural mucus lining which
protects the inner stomach. Common anti-inflammatory drugs
like Aspirin block the function of the COX-1 enzyme along
with another enzyme, COX-2 (see below). When the COX-1
enzyme is blocked, inflammation is reduced, but the
protective mucus lining of the stomach is also reduced,
which can cause stomach upset, ulceration, and bleeding
from the stomach and intestines.
Another enzyme, cyclooxygenase-2 (COX-2), also produces
these chemical messenger molecules, but the COX-2 enzyme is
located specifically in areas of the body that are
responsible for inflammation and not in the stomach. When
the COX-2 enzyme is blocked, inflammation is reduced. Since
the COX-2 enzyme does not play a role in the normal
function of the stomach or intestinal tract, medications
which selectively block COX-2 do not present the risk of
injuring the stomach or intestines.
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