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Mefenamic Acid 500mg Tablets

Mefenamic Acid 500mg Tablets (28 tablets)

Sorry, this treatment is currently out of stock.

Our UK based support team can help, either email us at support@theindependentpharmacy.co.uk

Product Information

  • Age: 18 Years +

    Maximum per order: N/A

  • Pregnancy: Not suitable

    Breastfeeding: Not suitable

Mefenamic acid is a prescription painkiller widely used for period pain, muscle cramps and heavy bleeding during periods.

Mefenamic acid works by reducing the hormones that cause inflammation and pain in the body and is not just prescribed for period pains; it is also used to treat other painful conditions such as arthritis and for pain control after surgical procedures. Mefenamic acid works by blocking chemicals made by the body called cyclo-oxygenase enzymes (COX) which in turn help to make other chemicals called prostaglandins. Period pains are caused by the production of prostaglandins in the lining of the womb and so taking Mefenamic acid can help to control the discomfort and pain experienced by some women by relieving their symptoms. It also reduces blood loss in women who suffer from heavy menstrual bleeding as prostaglandin production is known to be at a higher level in women who suffer from heavy periods.

Most women experience period pain at some time in their lives. Described in medical terminology as 'dysmenorrhoea', period pain is usually defined as muscle cramps in the lower abdomen, which can range from mild through to intense and painful, sometimes spreading to the thighs and around the body to the lower back. The pain varies from a dull, nagging ache or sensitivity to severe spasms which are caused by the muscular wall of the womb as it contracts and presses against adjacent blood vessels, interrupting the oxygen supply to the womb and thus triggering pain. Most period pains usually occur as the bleeding starts and may last for two or three days.

Prostaglandins are also produced by the body in response to certain diseases and conditions and even injury all of which may cause pain, swelling and inflammation. Therefore Mefenamic acid has a role to play in effectively controlling symptoms in other situations and it may also work in preventing the action of prostaglandins even after they have been produced.

*Prescription medicines are supplied subject to a medical consultation at the discretion of a doctor.

Mefenamic acid comes in tablet form and as with other anti-inflammatory medication, it is recommended that you take it either with or after food to avoid irritating the lining of the stomach.

Mefenamic acid is usually taken three times a day at mealtimes as this is one way to ensure that you remember to take it and that the dosages are fairly evenly spaced.

If you forget to take a dose at your usual time, then take it as soon as you remember, making sure it is not on an empty stomach. If it is nearly time for your next tablet then don't double up, just leave out the missed tablet and carry on with your dosage as normal. Do not take two tablets to make up for the missed dose.

Side effects may include the following symptoms:-

  • Nausea or feeling sick.
  • Vomiting.
  • Loss of appetite.
  • Fits.
  • Rapid heartbeats.
  • Reactions to sunlight.
  • A difference in the amount of urine passed, usually a decrease in quantity, the presence of blood in the urine, swelling of the ankles, a reduced salt level in the body. 
  • Drowsiness or disturbance to sleep patterns.
  • Depression.
  • Confusion or nervousness.
  • Hallucinations.
  • Impaired hearing or ringing in the ears, vertigo and dizziness.
  • Tingling or odd sensations.
  • Problems with eyesight.

You should always discuss any symptoms you may be experiencing with your doctor.

The active ingredient in Mefenamic acid tablets is Mefenamic acid.

To make up the complete product, Mefenamic acid tablets also contain:-

Microcrystalline cellulose, Sodium starch glycollate, Gelatin, Purified water, Magnesium stearate, Colloidal silicon dioxid, Croscarmellose sodium, Methanol, Methylene chloride, Ethylcellulose, Diethyl phthalate, Methylcellulose, Methocel, Opraspray yellow K – L - 6455

Please read all packaging and the Product Information Leaflet before taking any new medicine and inform your doctor of medicines you are currently taking or intend to take.

Take special care with Menefamic acid tablets in the following circumstances:-

  • If you suffer from asthma or wheezing attacks or if you have had asthma in the past.
  • If you have had an ulcer or some other problem affecting your stomach or intestines.
  • If you have any heart, liver or kidney problems.
  • If you are elderly.
  • If you suffer from epileptic fits.
  • If you have any abnormality of the blood.
  • If you are suffering from dehydration, perhaps because you have an illness which is causing vomiting or diarrhoea.
  • If you have frequent headaches.
  • If you drink alcohol.
  • If you have a connective tissue disorder e.g. Systemic Lupus Erythematosus (SLE) which results in joint pain, skin change and the disorders of other organs.
  • If you have a problem with the metabolism of sugar in your body.
  • If you are trying to get pregnant.

Your doctor or healthcare professional should always be aware of any medication that you are taking when you consult them. Signs of fever and inflammation may be reduced by Mefenamic acid and this could be relevant if your doctor is examining you for the presence of other conditions or illnesses.

Never exceed the recommended dose or the prescribed duration of treatment.

Mefenamic acid tablets may affect or be affected by the following medicines:-

  • Anticoagulant drugs which are drugs used to thin the blood such as heparin and warfarin.
  • Antiplatelet tablets which prevent blood clots e.g. clopidogrel.
  • Antihypertensives which are for the treatment of high blood pressure.
  • Diuretics which will encourage you to pass more water.
  • Lithium which is often prescribed for depression.
  • Medicines for the treatment of heart failure e.g. digoxin.
  • Quinolone antibiotics which are prescribed for infections e.g. ciprofloxacin, norfloxacin and nalidixic acid.
  • Any other NSAID such as aspirin, COX-2 selective inhibitors such as valdecoxib, paracoxib and refocoxib and ibuprofen. These are often prescribed for painful or inflammatory conditions.
  • Mifepristone which is used to terminate pregnancies.
  • Methotrexate which is used to treat certain tumours and other diseases including psoriasis and rheumatoid arthritis.
  • Ciclosporin or tacrolimus, used to suppress the body’s immune system following transplants or to treat diseases such as psoriasis and rheumatoid arthritis.
  • Corticosteroids used for the treatment of asthma and various inflammatory conditions, a typical prescribed medicine would be beclomethasone or prednisone.
  • Probenecid which is used for the treatment of swollen joints.
  • Drugs used to control diabetes e.g. Glibenclamide.
  • Antibiotic medication e.g. Gentamycin, Neomycin, Kanamycin.
  • Zidovudine which is an anti-viral drug.
  • SSRIs such as fluoxetine or sertraline prescribed for depression.
  • Antacids such as Milk of Magnesia, Gaviscon or Maalox.

DO NOT take Mefenamic Acid if:-

  • You know that you are allergic to Mefenamic Acid or any of the other ingredients in the tablets.
  • You currently have a stomach ulcer or bleeding.
  • You have suffered from stomach ulcers or bleeding on two or more occasions in the past.
  • You suffer from inflammatory bowel disease.
  • You show any signs of suffering from an allergy to aspirin, ibuprofen or other NSAIDs. An allergic reaction can include swelling of the face, lips, mouth, tongue or throat which may impair swallowing or breathing. Allergic signs may also include asthma, hay fever or a skin rash.
  • You have severe problems with your kidney or liver.
  • You suffer from severe heart failure or have had major heart surgery. Mefenamic Acid may be associated with a small increased risk of a heart attack known as ‘myocardial infarction’ or stroke so if you have heart problems or have previously had a stroke you may need to discuss alternative medication with your doctor. This also applies to people who may be at risk of heart attack so those suffering with high blood pressure, diabetes or who smoke.
  • You are in the final three months of pregnancy.
  • You are breast feeding.

Delivery & Shipping Information



We offer FREE standard tracked delivery on orders over £40.

The following delivery options are available:

  • Standard Tracked Delivery - 2/3 day delivery - £2.95
  • Express Tracked Delivery - 1/2 day delivery - £4.45
  • DPD Next Day - 1 working day - £6.95
  • Special Delivery (Guaranteed before 1pm) - £8.95
  • Saturday Guaranteed before 1pm - £10.45

Important Delivery Information

All our orders are sent out using Royal Mail (unless stated). We always aim to dispatch all Royal Mail orders received before 4pm the same working day. Any orders received after 4pm or over the weekend will be dispatched the next working day. We aim to dispatch all DPD orders placed before 3pm on the same working day. Orders will not be dispatched on weekends or bank holidays.

All orders are subject to approval by our team of doctors and pharmacists. Your delivery date in the checkout is subject to your consultation being approved by our healthcare team.

All orders can be fully tracked from your dispatch email and in your account.

We ensure all parcels are in plain packaging for discreet delivery of your medicines and pharmacy goods.

Deliveries containing pharmacy-only or prescription medicines may require a signature on receipt. 

Delivery is free for all NHS prescriptions.


Royal Mail

Royal Mail are the most widely recognised mail delivery company in the UK. Being on the UK’s 29 million doorsteps six days a week means they offer unparalleled price and convenience. The Independent Pharmacy uses Royal Mail’s Tracked 48, Tracked 24, and Special Delivery Guaranteed parcel services to offer reliable, fully-tracked delivery at very competitive prices. Your Royal Mail parcel will arrive with your normal daily delivery of post.

Please note: Royal Mail do not deliver on Sundays or Bank Holidays - this should be taken into account when ordering. 

If you are not home to accept your delivery, a card should be left by the Royal Mail representative. This card will provide details of where you can collect the order or how to arrange re-delivery.

Should you be unable to collect your missed delivery or arrange for your medication to be redelivered by Royal Mail, the pharmacy can resend your medication to the same, or a different address provided it has been returned to us and this happens within a 30 day window.

Once a package has been shipped with Royal Mail we advise that you are bound to the terms and conditions of their use together with the terms and conditions contained herein.

You have the right to cancel your order up to the point when your treatment is dispatched. The pharmacist must destroy any medication within 30 days of it being returned, even un-opened boxes, so we are not able to offer refunds once your treatment has been dispatched.



DPD Local is the most innovative parcel carrier around. Thanks to their industry-leading Predict service, they provide parcel recipients with a one hour delivery window, notified by email, so you don't have to wait in all day. What's more, it enables receivers to watch the progress of their delivery on a real-time map, all the way down to a final 15 minute time-slot. 

As well as keeping customers informed at every stage of the journey, DPD believe in maximising choice and convenience. That's why DPD provide access to a suite of options both on the day of delivery and the night before, allowing customers to take delivery of their goods in a way that suits. If you wish to reschedule, you can:

  • Select an alternative delivery date
  • Opt for delivery to a nominated neighbour
  • Have the parcel left in a specified safe place
  • Collect the parcel from your local DPD Pickup Shop
  • Upgrade delivery to By 12

Please note: DPD do not deliver on Saturdays, Sundays or Bank Holidays - this should be taken into account when ordering. 

Once a package has been shipped with DPD we advise that you are bound to the terms and conditions of their use together with the terms and conditions contained herein.

You have the right to cancel your order up to the point when your treatment is dispatched. The pharmacist must destroy any medication within 30 days of it being returned, even un-opened boxes, so we are not able to offer refunds once your treatment has been dispatched.


Forwarding houses

We are unable to ship orders to mailing or forwarding houses for onwards shipping to locations outside of the UK.


BFPO Postcodes

Unfortunately we are unable to deliver medicines to BFPO postcodes.


Remote Areas

Please be aware that Royal Mail Guaranteed services are not available to all customers in the UK, especially those that live in remote postcodes. Royal Mail advise customers of the following:

We deliver by 5.30pm the next working day in the following postcode areas:
AB30 - 39, 41 - 45, 51 - 56
GY9 Alderney (Channel Islands)
HS1, 3 - 9
IV21 - 28, 40 - 49, 51 - 56
KA27, 28
KW1 - 3, 5 - 15
KW16 Stromness Town only
PA20 (0&9)
PA28 - 38, 41 - 49, 76, 77
PH15, 17 - 26, 31 - 40, 49, 50


We deliver within two working days by 5.30pm to the following postcodes areas:
GY1 Herm (Channel Islands)
GY9 Sark (Channel Islands)
PA60 - 75, 78
ZE2, 3


We deliver within three working days by 5.30pm to the following postcode areas:
KW16 - non-Town
PH30, 41 - 44


Please note: This applies to our 'Special Delivery' and 'Saturday Guaranteed' services.



We are currently unable to ship orders outside of the UK.

We are unable to ship orders to mailing or forwarding houses for onwards shipping to locations outside of the UK.

Need to know more about Period Pain?

Visit our advice area or contact our support team

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Frequently Asked Questions

  • What should I avoid if I am taking Mefenamic Acid Tablets?

    Many pain relief medicines, which can be bought over-the-counter, contain a similar medicine to Mefenamic Acid - for example, Aspirin or Ibuprofen. Taking these products together with Mefenamic Acid can result in getting too much of this type of medicine. Always check the label to see whether a medicine contains; aspirin, ibuprofen, ketoprofen, diclofenac, or naproxen.

  • Why should I take Mefenamic acid?

    Mefenamic acid can help relieve the painful symptoms associated with heavy menstrual bleeding such as abdominal cramps, sensitivity and lower backache.

  • In what form is Mefenamic acid prescribed?

    Mefenamic acid comes in tablet form. It is recommended that the tablets are taken with food so either at or just prior to a meal to avoid possible stomach irritation occurring.

  • What type of medication is Mefenamic acid?

    Mefenamic acid is part of the class of medication known as Non-steroidal anti-inflammatories or NSAIDs. Othe NSAIDS include aspirin, ibuprofen and naproxen.

  • Are there any medicines I should avoid whilst taking mefenamic acid?

    You should avoid taking any similar medicines to mefenamic acid so aspirin, ibuprofen, ketoprofen or naproxen many of which are available over the counter. You should always tell your doctor or pharmacist about any other medicines that you are taking or may intend taking in the future in case they are not recommended alongside Mefenamic acid.

  • What other drugs will affect mefenamic acid?

    If you take antidepressants such as citalopram, escitalopram, fluoxetine (known as Prozac), fluvoxamine, paroxetine, sertraline (Zoloft), trazodone or vilazodone, you should make your healthcare professional aware. These medications can cause an adverse reaction if taken in conjunction with Mefenamic acid and may cause you to bruise or bleed more easily.

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  • 1 Complete a simple health questionnaire
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