COX1 and COX 2 Inhibitors; Aspirin, Ibuprofen, Indomethacin, Celecoxib, Rofecoxib, Parecoxib
ASPIRIN, AND other NONSTEROIDAL ANTI-INFLAMMATORY AGENTS (NSAIDS) - all have anti-inflammatory actions, especially at higher dosages. They are particularly effective for mild to moderate headache and for pain of musculoskeletal origin.
These anti inflammatory drugs have a similar mechanism of action, they inhibit cyclooxygenase (COX).
There are two major classes of COX: COX-1 is constitutively expressed, they involving blood clotting process and protect the lining of stomach and intestinal tract from digestive acids
but COX-2 is induced in the inflammatory state. COX-2, an enzyme responsible for inflammation and pain.
Aspirin, Indomethacin and ibuprofen are nonselective COX inhibitors.
While celecoxib, rofecoxib, parecoxib and etoricoxib are Selectively COX 2 inhibitors.
Paracetamol (acetaminophen) is also a COX-2 inhibitor, almost exclusively within the brain, and only minimally in the rest of the body; although its not considered an NSAID since it has only minor anti-inflammatory activity.
Gastric irritation is the most common side effect of non-steroidal anti inflammatory drugs, especially for aspirin. They may cause erosions and ulceration, leading to bleeding and perforation.
Because aspirin irreversibly inhibits Platelet COX and interferes blood coagulation process, bleeding is important risk of intaking aspirin and other anti inflammatory drugs.
Acetaminophen is considered as safest analgesic, because of its less side effects. Although at higher doses it is also hepatotoxic.
COX-2-selective drugs have similar analgesic potency and produce less gastric irritation, than the nonselective COX inhibitors.
The use of COX-2-selective drugs does not appear to lower the risk of nephrotoxicity compared to nonselective NSAIDs.
On the other hand, COX-2-selective drugs offer a significant benefit in the management of acute postoperative pain because they do not affect blood coagulation and do not causes bleeding.
Important side effects of COX-2 inhibitors, including celecoxib (Celebrex), are associated with increased cardiovascular risk, including cardiovascular death, myocardial infarction, stroke, heart failure, or a thromboembolic event.
Because of these side effects many selective COX 2 anti-inflammatory drugs, where withdrawn from the marker.
COX 2 inhibitors are contraindicated in patients in the immediate period, after coronary artery bypass surgery, and should be used with caution in elderly patients; and those with a history of or significant risk factors for cardiovascular disease.
Rofecoxib; (sold under the brand name Vioxx), was taken off the market in 2004 because of these concerns, while celecoxib; (sold under the brand name Celebrex), and traditional NSAIDs received boxed warnings on their labels.
COX inhibitors has been shown to reduce the occurrence of cancers and pre cancerous growths. Especially colorectal cancer.
Because COX-2 appears to be related to cancers and abnormal growths in the intestinal tract.
The FDA has approved Celebrex for treatment of familial adenomatous polyposis (FAP). COX-2 inhibitors are currently being studied in breast cancer and appear to be beneficial.
Moreover, a recent study with various malignant tumor cells showed that celecoxib could inhibit the growth of these cells, even though some of these cancer cells didn't even contain COX-2.
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By Sven Teschke - Own work, CC BY-SA 2.0 de, [ Ссылка ]
