Generic Name: Celecoxib
Systematic name: 4-[5-(4-methylphenyl)-3-(trifluoromethyl)pyrazol-1-yl]benzenesulfonamide
Chemical Formula: C17H14F3N3O2S
Description
Celebrex (also known as Celecoxib) is a non-steroidal sulfa anti-inflammatory drug (NSAID) and selective COX-2 inhibitor which is used in the treatment of rheumatoid arthritis, osteoarthritis, pain, acute pain, menstrual symptoms, painful menstruation and also to reduce numbers of rectum and colon polyps. It is known under the brand name Celebrex or Celebra for arthritis and Onsenal for polyps. Celebrex 200 mg was marketed by Pfizer company. It is available as a prescription medication in capsule form.
Medical Indications
Celebrex 200 mg is licensed for use in rheumatoid arthritis, osteoarthritis, pain, acute pain, menstrual symptoms, painful menstruation, ankylosing spondylitis and also to reduce number of colon and rectal polyps in patients with the familial adenomatous polyposis. Celecoxib was originally intended for pain relief and minimization of the gastrointestinal adverse effects usually seen with other NSAID drugs. In practice, its primary indication is long term and regular pain relief. Probably there is no advantage of using celebrex for short term or acute pain, except the case when other NSAID drugs or aspirin cause some cutaneous reactions.
Availability
Pfizer sells Celecoxib under the brand name Celebrex. It is available as oral capsules containing 50 mg, 100 mg, 200 mg and 400 mg with Celebrex 200 mg being the most popular dosage.
Celecoxib is not currently available as a generic medication in the USA. In other countries, e.g. India, Philippines, Vietnam Celebrex is legally available as a generic under other brand names such as Cobix, Celcoxx, Selecap etc.
Dosing
The usual adult dose of Celebrex is 200 mg or 100 mg once or twice a day.
Adverse effects
In theory the COX-2 selectivity of Celecoxib should result in a significantly lower incidence of gastrointestinal ulceration than traditional NSAIDs.
Special precaution
Patients with prior history of ulcer disease or gastrointestinal bleeding. Moderate to severe hepatic impairment, gastrointestinal toxicity can occur with or without warning symptoms.
Allergy
Celecoxib contains a sulfonamide moiety and may cause allergic reactions in those allergic to other sulfonamide-containing drugs. However, it has a low (about 4%) chance of inducing cutaneous reactions among persons who have a history of such reactions to aspirin or non-selective NSAID drugs.
Drug interactions
Celecoxib is predominantly metabolized by cytochrome P450 2D6. Caution must be exercised with concomitant use of 2D6 inhibitors, such as fluconazole. celecoxib may antagonize or increase the risk of renal failure with angiotensin converting enzyme-inhibitors and diuretics.
Pregnancy
Celecoxib is labeled as pregnancy category C. It is contraindicated during the third trimester of pregnancy due to teratogenic potential.
Risk of stroke and heart attack
There has been much concern about the possibility of increased riskfor heart attack and stroke in patients using Celecoxib. Like all NSAID medications, celecoxib carries an FDA-mandated "black box warning" for cardiovascular and gastrointestinal risk. The American Heart Association warned that celecoxib should be used "as a last resort on patients who have heart disease or a risk of developing it", and suggested that paracetamol, or certain older NSAIDs, may be safer choices for chronic pain relief in such patients.
The cardiovascular risks of celecoxib are controversial, with apparently contradictory data produced from different clinical trials.
Pharmacology
Celecoxib is a highly selective COX-2 inhibitor and primarily inhibits this isoform of cyclooxygenase, whereas nonselective NSAIDs (like asprin, naproxen and ibuprofen) inhibit both COX-1 and COX-2. COX-1, traditionally defined as a constitutively-expressed “housekeeping” enzyme, is the only isoenzyme found in platelets and plays a role in the protection of the gastrointestinal mucosa, renal hemodynamics, and platelet thrombogenesis. On the contrary, COX-2 is extensively expressed in cells involved in inflammation and is upregulated by bacterial lipopolysaccharides, cytokines, growth factors, and tumor promoters. Celecoxib is approximately 10-20 times more selective for COX-2 inhibition over COX-1. It binds with its polar sulfonamide side chain to a hydrophilic side pocket region close to the active COX-2 binding site. This selectivity 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 NSAID medications.
Celecoxib inhibits COX-2 without affecting COX-1. COX-1 is involved in synthesis of prostaglandins and thromboxane, but COX-2 is only involved in the synthesis of prostaglandin. Therefore, inhibition of COX-2 inhibits only prostaglandin synthesis without affecting thromboxane (TXA2) and thus offer no cardioprotective effects of non-selective NSAID drugs.
