Mefenamic Acid
Introduction
Mefenamic acid is an anti-steroidal antiinflammatory drug, an NSAID. It is used in musculoskeletal and joint disorders such as alkylosing spondylitis, osteoarthritis and rheumatoid arthritis including juvenile idiopathic arthritis. It is also used in mensrual pain, headache, dental pain, postoperative and postpartum pain.
| Generic Name 藥名 | HA Code 藥物代碼 | Classification藥物分類 |
|---|---|---|
| Mefenamic Acid Capsule 250 mg | P1S1S3 |
Mechanism of Action
Non-opioid Analgesic (NSAID) Anti-inflammatory agent, Nonselective COX inhibitor, inhibits COX-1 and COX-2
Dosage
In the treatment of rheumatic disorders:
Oral: 500 mg three times daily.
It is recommended that it should not be given for longer than 7 days at a time.
Administration in children
Oral dose in those over 6 months of age: 25mg/kg daily in divided doses.
Side Effects
As for NSAIDs in general.
Naproxen suppositories can cause rectal irritation and occasional bleeding.
Naproxen should be used with caution in renal impairment, and use is not recommended in patients whose creatinine clearance is less than 20 mL/min.
Common side effects include heartburn, nausea, dyspepsia, diarrhoea, constipation, gastrointestinal ulceration/bleeding, headache, dizziness, rash, salt and fluid retention, and high blood pressure.
Note: Naproxen poses an intermediate risk of stomach ulcers compared with ibuprofen, which is low-risk, and indomethacin which is high-risk.
Effects on the blood: localized spontaneous bleeding, bruising and prolonged bleeding time have been reported.
It also increases the risk of heart attack, stroke, kidney failure and liver failure.
NSAID can also worsen asthma.
Naproxen may cause muscle cramps in the legs in 3% of people.
Cardiovascular risk
Chronic ibuprofen use has been found correlated with risk of progression to hypertension and myocardial infarction (heart attack). Both the U.S. Food and Drug Administration (FDA) and The European Medicines Agency (EMA) issues warnings of increased heart attack and stroke risk.
Skin
NSAIDs has been associated with the onset of bullous pemphigoid. It can also cause serious skin adverse events such as exfoliative dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis which can be fatal.
