Mefenamic Acid

  • Provides effective treatment for period pain
  • Very fast acting nonsteroidal anti-inflammatory drug (NSAID)
  • For best results, take tablets on the day of your period

Please note brand received may vary

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From As low as £34.99

Disclaimer: The prices displayed should only be used as a reference of our prices for this medicine. If you are approved for treatment, our prescribers will decide on a suitable treatment for you to jointly consider.

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order before 2pm

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What is Mefenamic Acid?

Mefenamic Acid is a member of the anthranilic acid derivatives class of nonsteroidal anti-inflammatory drugs (NSAIDs). It is used to treat period pain and painful menstrual cycles.

It is sometimes sold under the brand name Ponstan.

What is Mefenamic Acid used to treat?

This medication is primarily used to treat mild to moderate period pain. It works by inhibiting both isoforms of COX and prevents the formation of prostaglandins, which causes pain, providing a short-term solution to this issue.

Who can use Mefenamic Acid?

Mefenamic Acid may not be suitable for certain people to take. Always read the patient information leaflet thoroughly before you start to use this medication.

This medication is not suitable for anyone under the age of 12 years old.

Speak to your doctor before taking Mefenamic Acid if you suffer from any of these conditions:

  • You are using treatments for asthma
  • You have epilepsy
  • You have high blood pressure (Hypertension)
  • You have high cholesterol
  • You have high blood sugar levels
  • You have any connective tissue disorders
  • You have kidney problems
  • You have liver problems
  • You have or have ever had a stomach or duodenal ulcer
  • You have Chron's disease, ulcerative colitis or any inflammatory bowel disorders
  • You have porphyria
  • You are currently taking any other medications (refer to the Warnings and Drug Interactions tab for full details)
  • You have had an allergic reaction to a NSAID, or any medicine, in the past

Possible Side Effects

As is the case with all medications, taking Mefenamic Acid comes with the risk of certain side effects, although not everyone will suffer from them.

Below are common Mefenamic Acid side effects you may experience; speak to your doctor if any of these effects concern you or don't go away:

  • Mouth ulcers
  • Indigestion
  • Heartburn
  • Feeling sick
  • Being sick
  • Wind
  • Stomach pain
  • Diarrhoea
  • Skin rash

If you suffer from diarrhoea or a skin rash, contact your doctor as soon as possible.

This list is not exhaustive. Always read the patient information leaflet thoroughly before you start your treatment, for a full list of adverse effects.

A list of rarer, more serious reactions can be found on the Side Effects tab on this page.

Mefenamic Acid Dosage

All our doctors and pharmacists follow NICE guidelines when prescribing Mefenamic Acid.

Always take Mefenamic Acid exactly as instructed by your doctor. Read the patient information leaflet thoroughly before you start to take it. Speak to your doctor if you are unsure of anything.

The average dose is 500mg (either taken as one 500mg tablet or two 250mg tablets).

Your doctor will instruct you to take Mefenamic Acid three times a day. To treat period pain, they will probably tell you to take it for a few days of each month, beginning on the first day of your bleeding.

Take Mefenamic Acid with food so your stomach is properly lined; this will aid against indigestion.

Swallow the tablets whole with a drink of water. Do not chew or crush the tablets.

What if I forget to take a dose?

If you accidentally miss a dose, just take it as soon as you remember. If it is almost time for you to take your next dose, skip the dose you missed and continue taking Mefenamic Acid as usual.

Never double dose to try and make up for missing a previous dose.

Space your doses out evenly throughout the day and try to take them at the same time each day, this will help you to get into a routine.

What if I take more than I am supposed to?

If you accidentally take more of this medication than you are told to, you should speak to your doctor if you become worried, take more than one extra dose, or experience any adverse effects.

Mefenamic Acid

Is it suitable for children?

Children who are aged 12 years old and above can use Mefenamic Acid when they have been given a prescription by a doctor.

How much does Mefenamic Acid cost?

You can purchase it from Medicine Direct for £24.99. You also have the option of free delivery or next day delivery if you order before 2 PM. We despatch all orders in discreet packaging, providing you with confidentiality and discretion on your medicine.

Is it the same as ibuprofen?

Ibuprofen is also a nonsteroidal anti-inflammatory drug (NSAID), but it is not the same product as Mefenamic Acid and should not be taken at the same time.

Can you purchase it over the counter?

This medicine is only available to purchase when you have been prescribed it by your doctor

I'm pregnant, can I take this medicine?

You should make sure your doctor is aware if you are pregnant; Mefenamic Acid may not be suitable for women to use if they are pregnant. You should also inform your doctor if you think you may be pregnant, are trying to get pregnant, or are breastfeeding.

Can I use it while on the pill?

You should consult your doctor about this before using Mefenamic Acid. Please note that long-term use of some NSAIDs may reduce female fertility, which is reversible on stopping treatment.

How do I take it?

The usual daily dose is 500mg. You should take this medication three times a day, beginning on the first day of period pain. Swallow the tablets whole with a drink of water and take them on a full stomach. Always read the patient information leaflet thoroughly for comprehensive instructions. Speak to your doctor if you are unsure of anything.

Can I drink while taking Mefenamic Acid?

Try to limit how much you drink while taking this medication. Alcohol can increase the risk of stomach side effects.

How long does it take for Mefenamic Acid to relieve period pain?

Mefenamic Acid is a fast-acting nonsteroidal anti-inflammatory drug (NSAID), but to effectively treat period pain, you will need to take the medication consistently, in accordance with your doctor's instructions.

How does Mefenamic Acid work to stop heavy periods?

Mefenamic Acid gets to work by inhibiting both isoforms of COX and prevents the formation of prostaglandins.

Mefenamic Acid Side Effects

Always read the patient information leaflet thoroughly before starting any new medicine, for a comprehensive list of side effects. Speak to your doctor if you have any questions or concerns at all, before you start to use Mefenamic Acid.

Seek immediate medical attention if you display any of these serious side effects:

  • You have blood in your stools
  • You have black stools
  • You have blood in your vomit
  • You have severe stomach pains
  • You have sudden slurred speech
  • You have unexplained numbness in any part of your body

In rare cases, you may experience a severe allergic reaction. Call 999 or go to A&E immediately if you experience any of the following symptoms:

  • You are wheezing
  • You have swelling of the lips, tongue, throat, face or mouth
  • You have tightness in the chest or throat
  • You are finding it difficult to speak or breathe
  • You have a skin rash that is swollen, red, itchy, blistered or peeling

You may require immediate treatment in hospital.

Mefenamic Acid Warnings and drug interactions

Always inform your doctor of any other medicines you are currently taking. This includes both prescription and non-prescription medications, herbal remedies, vitamins and supplements.

Certain drugs may interact with mefenamic acid and hinder its effectiveness and/or increase your risk of side effects.

Be certain to tell your doctor if you are currently taking:

  • Medicines for high blood pressure
  • Any other NSAIDs, such as ibuprofen and Naproxen
  • Any ACE inhibitors
  • Any diuretics (water pills)

Read the patient information leaflet for a comprehensive list of drug interactions.

Non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs) can increase your risk of a stroke or heart attack. Seek immediate medical attention if you experience any of these symptoms:

  • Chest pain
  • Shortness of breath or trouble breathing
  • Sudden weakness or numbness in one part or side of the body
  • Sudden slurred speech.

Only ever purchase medicine online if it is from a pharmacy registered with the General Pharmaceutical Council, like Medicine Direct. If you order with us before 2 PM, we provide next day delivery via Royal Mail.

If you have any questions or concerns at all, we strongly advise you to discuss these with your doctor before you start using a new medication.

Pregnancy and breastfeeding

Mefenamic Acid is not recommended during pregnancy. Make sure your doctor is aware if you are currently pregnant, are trying to get pregnant, or think you might be pregnant.

Similarly, ensure you tell your doctor if you are currently breastfeeding. Small amounts of Mefenamic Acid may get into your breast milk and may be passed on to your baby.

Mefenamic Acid Ingredients

The active ingredient is mefenamic acid.

Other ingredients also contained are: stearic acid, croscarmellose sodium, sodium lauryl sulfate, colloidal silicon dioxide, microcrystalline cellulose, gelatin, FD&C Yellow No.10, FD&C Yellow No.6, FD&C Blue No.1 and titanium dioxide.

Delivery Company Delivery Service Price Details
Royal Mail UK Delivery Standard UK Tracked £2.99 3 - 4 Working Day Delivery
DPD UK Next Day Delivery Next Day Delivery - Tracked £5.95 Order by 2pm (subject to Dr approval) Next Working Day Delivery
DPD UK Next Day Delivery Next Day Tracked Morning Delivery by 12:00pm £12.95 Next Working Day Morning Delivery by 12:00pm
DPD UK Next Day Delivery Tracked Saturday Delivery £9.95

Delivery specified for Saturday

Order Friday by 2pm (subject to Dr approval)

Please note that next day delivery to Northern Ireland, Scottish Highlands & Islands and British Isles cannot be guaranteed. Please contact our team for more information.

Written byHussain Abdeh MPharm: 2211840

Updated on: 04/06/2021

This content has been written by our Superintendent Pharmacist Hussain Abdeh and has been medically reviewed by our Pharmacist Sonia Khan

Hussain Abdeh Superintendent Pharmacist at Medicine Direct

Hussain Abdeh
MPharm: 2211840

Pharmacist Independent Prescriber

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