Celecoxib

Celecoxib (sel-eh-cox-ib) is a NSAID that inhibits prostaglandin synthesis by inhibiting COX-2 and is typically used for rheumatoid arthritis and osteoarthritis, primary dysmenorrhea, pain following surgery or musculoskeletal pain. It was initially approved by the FDA in the USA in 1998 and in Australia in 1999. Celebrex (Pfizer) is the most commonly known brand name of celecoxib.

Mechanism of action:
Celecoxib is a selective inhibitor of cyclooxygenase-2 (COX-2) which is responsible for synthesis of prostaglandin in the pain and inflammation pathway.

Pharmacokinetics:
Well absorbed orally
Plasma levels peak in 2-3 hours
97% bound to plasma proteins (mainly albumin); crosses placenta
Metabolised in liver, predominantly by cytochrome P450 2C9.
Excretion: faeces (~50%), urine (~25%)
Half life is 11 hours

Adverse effects:
Most common are abdominal pain, diarrhea, dyspepsia, flatulence, peripheral oedema, dizziness, pharyngitis, rhinitis, sinusitis, upper respiratory tract infection, rash.
Gastrointestinal effects have a lower incidence than the COX-1 inhibitors.
Less common, but more serious effects are cardiovascular thrombotic events; GI bleeding, ulceration and perforation; hepatotoxicity; hypertension; heart failure and edema; renal toxicity and hyperkalemia; anaphylactic reactions; serious skin reactions; hematologic toxicity

Contraindications:
Known hypersensitivity to celecoxib or any components of the drug product.
Previous allergic-type reactions to sulfonamides (Celecoxib has a sulfur molecule).
A history of asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs.
Pain relief after coronary artery bypass graft surgery, due to its cardiovascular risk.
Should not be used during pregnancy.

Dosage:
Generally, 200mg/day or 2x100mg/day
For acute pain, maybe initial dose of 400mg
Reduce daily dose by 50% in those with moderate hepatic impairment

Precautions:
Has as an FDA mandated box warning for caution about the risk for cardiovascular and gastrointestinal effects:

Interactions:
Monitor patients for bleeding if taking drugs that interfere with haemostasis (eg warfarin, aspirin).
Celecoxib may diminish the antihypertensive effect of angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARB), or beta-blockers, so monitor blood pressure.
Can reduce natriuretic effect of furosemide and thiazide diuretics.
Can increase the serum concentration and prolong half-life of digoxin.

Brand names: Celebrex, Onsenal, Elyxyb, Seglentis, Celebra and others
Chemical formula: C₁₇H₁₄F₃N₃O₂S
Systematic chemical name: 4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-
pyrazol-1-yl] benzenesulfonamide
Availability: Prescription only
Do not confuse with: Celebrex (brand name); Celexa (citalopram, antidepressant); Cerebra (huperzine A, ‘cognitive enhancer’)

Patient education:
Informed about the risks and potential side affects.
Avoid alcohol (as increases GI risks).
Can take with or without food.

In Australia, celecoxib is on the National Podiatry Scheduled Medicines List for use by authorised podiatrists.

Other nonsteroidial anti-inflammatory drugs (NSAID’s):

Preferential COX-2 Inhibitors
Diclofenac	Nimesulide	Aceclofenac	Meloxicam	Etodolac

Selective COX-2 Inhibitors
Celecoxib	Etoricoxib	Parecoxib	Rofecoxib

Nonselective COX-2 Inhibitors
Salicylates:	Aspirin
Propionic acid derivatives:	Ibuprofen	Naproxen	Ketoprofen	Flurbiprofen
Enolic Acid derivatives:	Prioxicam	Tenoxicam
Acetic Acid derivatives:	Ketorolac	Indomethacin	Nabumetone
Pyrazolane derivatives:	Phenylbutazone	Oxyphenbutazone
Indeneacetic acid derivatives:	Sulindac
Fenamate:	Mephenamic acid

Analgesic & Antipyretics with a weak anti-inflammatory action
Para aminophenol derivatives:	Paracetamol (Acetaminophen)
Benzoxazocine derivatives:	Nefopam
Pyrazolone derivatives:	Propiphenazone	Metamizol

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