Mefenamic acid (250 mg) is a non‑steroidal anti‑inflammatory drug (NSAID) commonly used to treat mild to moderate pain and inflammation, especially menstrual (dysmenorrhea) pain. It’s typically sold as an oral tablet, and the 250 mg strength is one of the most common therapeutic doses.
How it works
- COX inhibition – Mefenamic acid blocks cyclo‑oxygenase (COX‑1 and COX‑2) enzymes, reducing the production of prostaglandins that mediate pain, fever, and inflammation.
- Anti‑inflammatory & analgesic – By lowering prostaglandin levels, it dampens the inflammatory response and relieves pain.
Typical dosing (adult)
- Menstrual pain: 250 mg every 6–8 hours as needed. A common regimen is 3–4 tablets over a 24‑hour period (max 1200 mg/day).
- Other mild to moderate pain: 250 mg every 6 hours as needed, up to 1000 mg/day.
- First dose: Often a 500 mg “loading” dose is taken, then 250 mg maintenance.
Note: Always follow the prescribing information or your clinician’s instructions. The 250 mg tablets are the standard maintenance dose; higher doses (e.g., 500 mg) are used for a short “loading” phase or for more severe pain.
How to take it
- With food or milk – helps reduce stomach irritation.
- Swallow whole – do not crush or chew.
- Timing – can be taken before meals if you’re taking it for dysmenorrhea.
Common side effects
- Gastro‑intestinal: nausea, heartburn, stomach pain, diarrhea, or constipation.
- Headache or dizziness.
- Rare: rash, allergic reactions, or more serious GI bleeding/ulcers.
If you experience severe stomach pain, vomiting blood, black/tarry stools, persistent dizziness, or signs of an allergic reaction (rash, swelling, difficulty breathing), seek medical care promptly.
Contraindications & cautions
- Peptic ulcer disease or history of GI bleeding.
- Chronic kidney disease or significant liver impairment.
- Pregnancy – generally avoided after 28 weeks; use only if benefits outweigh risks.
- Concurrent NSAID use (e.g., ibuprofen, naproxen) can increase GI risk.
- Anticoagulants – may increase bleeding risk.
Always inform your healthcare provider of any other medications, supplements, or medical conditions.
Interactions
- Anticoagulants (warfarin, heparin): ↑bleeding risk.
- Other NSAIDs or steroids: additive GI toxicity.
- ACE inhibitors or diuretics: may reduce renally excreted NSAIDs’ efficacy.
- Cimetidine can increase mefenamic acid plasma levels.
Storage
- Keep at room temperature, away from moisture and direct sunlight.
- Keep out of reach of children.
Bottom line
Mefenamic acid 250 mg is a widely used NSAID for menstrual pain and other mild to moderate aches. It works by blocking prostaglandin production, but like all NSAIDs, it can irritate the stomach and increase bleeding risk. Use it only as directed, take it with food or milk, and be mindful of possible interactions and contraindications. If you’re unsure whether it’s right for you, talk to a pharmacist or your healthcare provider.