Mefenamic Acid

NSAID

Also known as: Ponstan

An NSAID commonly used for menstrual cramps, headaches and mild-to-moderate muscle or joint pain.

Uses

Menstrual pain (dysmenorrhoea)
Mild to moderate pain
Rheumatoid arthritis
Osteoarthritis
Headache/toothache

Common brands available in Hong Kong

Ponstan (Pfizer)
Ponstan SF

Common formulations

250mg (capsule)
500mg (film-coated tablet, some markets)

What is Mefenamic Acid used for?

Mefenamic acid is a non-steroidal anti-inflammatory drug (NSAID) that works by inhibiting cyclooxygenase (COX) enzymes, reducing prostaglandin production to relieve pain, inflammation and fever. It is commonly used for menstrual pain, headache, toothache and mild-to-moderate musculoskeletal pain.

How to take Mefenamic Acid and adjust the dose

Typical adult and adolescent (14+) dosing is an initial 500mg dose, followed by 250mg every 6 hours, generally not exceeding 7 consecutive days of use. Take with food to reduce GI upset. This is drawn from generic labelling and Pfizer's Ponstan information — moderate confidence; confirm with the package insert or a pharmacist for the exact HK-registered dose.

Mefenamic Acid side effects

Common: nausea, vomiting, mild indigestion, diarrhoea
Serious (rare): GI bleeding/ulceration, kidney injury, liver dysfunction, severe skin reactions (Stevens-Johnson syndrome), anaemia

Who should not take Mefenamic Acid?

Known allergy to mefenamic acid or other NSAIDs
Active GI ulceration or inflammation
Aspirin-sensitive asthma
Severe renal or hepatic impairment
Late pregnancy and breastfeeding (consult doctor)
Should not be used around CABG surgery
Not recommended for more than 7 consecutive days

Check the Department of Health Drug Office register →

Sources: www.mims.com · www.drugs.com · labeling.pfizer.com · www.chp.gov.hk

This page is general reference information only, not medical advice. Always confirm dosage, interactions, and whether this medicine is suitable for you with a pharmacist or doctor before use.

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