Mefenamic Acid Available Dosage Strengths
Mefenamic acid is commercially available as oral capsules in 250 mg and 500 mg strengths 1, 2, 3, 1, 3, 4, 5.
Dosage Forms and Strengths
According to multiple ESMO (European Society for Medical Oncology) clinical practice guidelines consistently published from 2008-2011, mefenamic acid is widely available as:
- Capsules: 250 mg
- Capsules: 500 mg
These are the standard oral formulations available to the public across multiple countries 1, 2, 1, 5.
Standard Dosing Information
The maximum daily dose is 4 × 500 mg = 2000 mg per day 1, 2, 3, 1, 3, 4, 5. This represents the upper limit for safe administration in adults.
Typical Dosing Regimen
According to FDA labeling, the standard dosing approach is 6:
- Initial dose: 500 mg (2 capsules of 250 mg)
- Maintenance: 250 mg every 6 hours as needed
The onset of action occurs approximately 30 minutes after oral administration 1, 2, 1, 5.
Important Clinical Considerations
Gastrointestinal and renal toxicity are the primary concerns with mefenamic acid use 1, 2, 1, 5. When used for extended periods, gastric protection is recommended 1, 5.
The drug should not be administered to patients with pre-existing renal disease or significantly impaired renal function 6. Mefenamic acid is metabolized hepatically via CYP2C9 and excreted renally (52% as glucuronides) and fecally (20%) 6.
Duration of Use
Mefenamic acid is most commonly used for short-term treatment (7 days or less), particularly for conditions like dysmenorrhea, dental pain, and acute postoperative pain 7. The elimination half-life is approximately 2-4 hours 6.