Meds and you

27 September 2013

Mefenamic Acid

Mefenamic acid is a non-steroidal anti-inflammatory medication.


Mefenamic acid is the active ingredient of Adco-Mefenamic Acid Capsules (Nappi Code: 883102-004/012), Adco-Mefenamic Acid Suspension (Nappi Code: 875643-019/027), Fenamin Capsules (Nappi Code: 797707-026), Fenamin Tablets (Nappi Code: 797715-010), Fenamin Suspension (Nappi Code: 797715-010), Ponac Capsules (Nappi Code: 796433-003), Ponac Tablets (Nappi Code: 794201-008), Ponac Suspension (Nappi Code: 793264-006/014), Ponstan Capsules (Nappi Code: 756148-006), Ponstan Tablets (Nappi Code: 756164-001), Ponstan Suspension (Nappi Code: 756156-009/017/025), Ponstan Suppositories (Nappi Code: 807435-007), Ponstel suspension (Nappi Code: 810398-001/028), Ponstel Capsules (Nappi Code: 812250-001/036), Ponstel Tablets (Nappi Code: 8103711-006) and Sandoz Mefenamic Acid Capsules (Nappi Code: 741167-042/018).

General information
Mefenamic acid is a non-steroidal anti-inflammatory medication.

It is prescribed to relieve inflammation, swelling, stiffness, pain and fever. It is of particular use in arthritic and muscular conditions, and for broad spectrum pain relief, including headache, menstrual pain and discomfort, and dental pain.

Mefenamic acid is also used for the treatment of excessive menstrual bleeding.

This medication does not cure the underlying condition responsible for pain or inflammation, but simply keeps the symptoms under control.

Mefenamic acid may irritate or even damage your stomach. To reduce this, it is advised to take this medication with food.

This risk increases the longer you take this medication, or if you are also taking corticosteroid medications such as prednisone, anticoagulants (blood thinning medication) such as warfarin, or if you smoke or consume alcohol while being treated with mefenamic acid.

How does mefenamic acid work?
Mefenamic acid blocks the production of chemicals in the body that are responsible for pain, fever, swelling and inflammation.

Fast facts

Drug schedule: schedule 2, 3
Available as: mefenamic acid is available as tablets, capsules, suspension and as a suppository.
What does it do? Mefenamic acid reduces pain, and inflammation.
Overdose risk: medium
Dependence risk: low
Is mefenamic acid available as a generic? yes
Is mefenamic acid available on prescription only? no (depending on indication)

User information

Onset of effect: within 2 hours
Duration of action: up to 8 hours
Dietary advice: mefenamic acid should be taken with a meal to minimise gastrointestinal irritation.
Stopping this medicine: mefenamic acid can be safely stopped when it is no longer needed.
Prolonged use: the likelihood of adverse effects increase with prolonged use. Your doctor may perform periodic liver and kidney function tests, while also examining you for possible gastrointestinal damage.

Special precautions
Consult your doctor before using this drug if:

  • you have asthma

  • you have a kidney or liver disease

  • you have a stomach ulcer

  • you have inflammatory bowel disease

  • you have a bleeding disorder

  • you have porphyria

  • you have epilepsy

  • you have high blood pressure

  • you are taking blood thinning medication

  • you are allergic to aspirin or any other medication

  • you are taking other medication

Pregnancy: avoid. Potential risk to the foetus has been reported. Consult your doctor before use, or if you are planning to fall pregnant.
Breastfeeding: avoid. It is unknown how this medication may affect your baby. Consult your doctor before use.
Porphyria: avoid. It is unknown how this medication may affect your condition. Consult your doctor before use.
Infants and children: mefenamic acid is safe to use at the indicated dosages. It should only be prescribed by a doctor.
The elderly: caution is advised in the elderly as side effects may be more likely. The dose may need to be adjusted.
Driving and hazardous work: caution is advised as use of this medication may lead to dizziness, light-headedness and/or sedation. Avoid such activities until you know how this medication affects you.
Alcohol: avoid concomitant use of alcohol with this medication as it may worsen stomach irritation.

Possible side effects

Side Effect
Consult your doctor

Only if severe
In all cases




abdominal pain






visual disturbances


difficulty swallowing/breathing


yellow tinge to skin/eyes




blood in vomit

dark tarry stools




Drug interactions

blood pressure medication reduced pressure lowering effect
alcohol potential gastrointestinal symptoms
warfarin risk of bleeding
asthma medication reduced effect of asthma medication; risk of asthma attack
cardiac glycosides, digoxin risk that heart failure may be more severe
corticosteroids potential gastrointestinal symptoms
ciclosporin potential mefenamic acid toxicity
methotrexate potential methotrexate toxicity
digoxin potential digoxin toxicity
lithium potential lithium toxicity
diuretics potential risk of kidney damage
blood glucose lowering drugs risk of prolonged low blood sugar
baclofen potential baclofen toxicity
other NSAID’s potential risk of gastrointestinal bleeding
probenecid risk of mefenamic acid toxicity
quionolone antibiotics risk of seizures
tacrolimus increased risk of kidney damage
zidovudine increased risk of zidovudine toxicity

Disease interactions
Consult your doctor before using this drug if you have asthma, kidney or liver disease, a stomach ulcer, inflammatory bowel disease, a bleeding disorder, porphyria, epilepsy, high blood pressure or if you are allergic to aspirin or any other medication.

Overdose action
A small overdose is no cause for concern. In case of intentional large overdose seek emergency medical attention.

Recommended dosage
Adults: 750-1500 mg/day

This material is not intended to substitute medical advice, but is for informational purposes only. Please consult a physician for specific treatment and recommendations.

Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.