Etoricoxib
Catergory: Etoricoxib
| Generic Name 藥名 | HA Code 藥物代碼 | Classification藥物分類 |
|---|---|---|
| Arcoxia Tablet 120 mg | P1S1S3 |
Mechanism of Action
Anti-inflammatory agent, Non-steroidal anti-inflammatory drug (NSAID) Selective COX-2 inhibitor
Dosage
For osteoarthritis |Oral: 30 mg daily once daily, increased to 60 mg once daily if necessary.
For rheumatoid arthritis and ankylosing spondylitis
Oral: 60 mg once daily, increased to 90 mg once daily if necessary.
For gouty arthritis
Oral: 120 mg once daily.
Such higher doses should only be used for acute symptomatic period and for a maximum of 8 days.
For postoperative dental pain
Oral: 90 mg once daily for a maximum of 3 days.
Administration in hepatic impairment
Mild hepatic impairment: 60 mg once daily
Moderate hepatic impairment: 60 mg every other day or 30 mg once daily.
Etoricoxib should not be given to patients with severe hepatic impairment.
Side Effects
Common side effects include:
- Abdominal pain, nausea and diarrhea.
Serious side effects may include:
- Heart attacks
- Strokes
- Gastrointestinal perforation
- Gastrointestinal bleeding
- Kidney failure
- Anaphylaxis
It is generally accepted that COX-2 inhibitor may cause less gastrotoxicity than that seen with the non-selective inhibition of the traditional NSAIDs. However, reports that upper gastrointestinal perforation, ulceration and bleeds have occurred with etoricoxib treatment and should not be used in patients with active gastrointestinal ulceration or bleeding.
Pharmacokinetics
Peak plasma concentrations occur in about 1 hour in fasted adults; food delays absorption by about 2 hours.
Plasma protein binding is about 92%. Celecoxib is metabolized in the liver mainly by the cytochrome P450 isoenzyme CYP3A4. It is eliminated mainly as metabolites in the urine (70%) and 20% in the faeces.
The plasma elimination half-life is about 22 hours.
Celecoxib is distributed into breast milk.
Drug Management
Monitoring
- Regular physical examination to detect edema and signs of central nervous side effects.
- High Blood pressure should be controlled before starting treatment and monitored for 2 weeks afterwards ten regularly thereafter.
- Periodic serum electrolyte (sodium, potassium, chloride) measurements
- complete blood counts and
- assessment of liver enzymes as well as creatinine (renal function) should be performed.
This is particularly important if Indomethacin is given together with an ACE inhibitor or with potassium-sparing diuretic (e.g. spironolactone), because these combinations can lead to hyperkalemia and/or serious kidney failure.
Drug interaction
- the metabolism of etoricoxib is mediated by the cytochrome P450 isoenzyme CYP3A4. Use of other drugs that inhibit or induce by this isoenzyme may result in changes in plasma concentration of etoricoxib. Rifampicin, a potent inducer of CYP isoenzymes, has decreased plasma concentrations of etoricoxib
- Increases the blood thinning effects of warfarin by displacing them from their plasma protein binding and increases their free concentrations in the bloodstream, so increases the risk of bleeding
- Increase the risk of adverse effects of lithium, methotrexate and cardiac glycosides by lowering their excretion via the kidneys.
- Increase risk of kidney failure if given with ACE inhibitors such as lisinopril, ciclosporin, tacrolimus and diuretics, such as hydrochlorothiazide.
- Increase risk of hyperkalaemia with ACE inhibitors and potassium-sparing diuretics such as spironolactone.
- Use of more than one NSAID together (including aspirin) should be avoided because of the increased risk of adverse effects.
- It adds to the risk of gastrointestinal bleeding and ulceration when used with steroids, the SSRIs (such as sertraline or fluoxetine), the SNRI venlafaxaine, the antiplatelet clopidogrel, bisphosphonates or pentoxifylline.
Many NSAIDs, but particularly indomethacin, cause lithium retention by reducing its excretion by the kidney. Thus, indomethacin users have an elevated risk of lithium toxicity. For patients taking lithium (e.g. for treatment of bipolar disorder), less toxic NSAIDs such as sulindac is preferred. All NSAIDs, including indomethacin, also increase plasma renin activity and aldosterone levels, and increase sodium and potassium retention. Vasopressin activity is also enhanced. Together these may lead to:
