Mefenamic acid tablets are a targeted painkiller offering relief from menstrual cramps and associated pain. Each tablet contains the active ingredient mefenamic acid, which is a non-steroidal anti-inflammatory drug (NSAID).

Period pains are caused by the shedding of the uterus lining (endometrium) that occurs approximately every month when a woman does not become pregnant. To help the body effectively shed this lining the uterus contracts which causes pain and cramps in the lower abdomen. The contraction is caused by the production of chemicals in the body called Prostaglandins. The pain can also radiate to the back and legs. Many women will know that periods can also cause other pains in the body such as headaches. Thankfully this medication can also reduce the unpleasant sensation associated with these.

Mefenamic acid is a NSAID (Non-steroidal Anti-inflammatory drug). NSAIDs block the production of prostaglandins which in turn reduces the contraction of the uterus. This reduces the painful sensation during your period and also reduces the amount of blood lost.

Mefenamic acid usually take 30 - 60 minutes to take effect. As the dose is taken three times daily before and during your period you will have relief throughout the day and time of your period.

If your pain is particularly bad you can take paracetamol at the same time and also use heat pads on the abdomen and lower back. Be sure to check you are only taking the recommended dose of each medication.

There are a range of treatments that can be used for pain relief during your period. You can find the full range of pain relief treatments here:

If you are affected by heavy bleeding, you can alternatively use Tranexamic acid, this is a different NSAID treatment which primarily helps to reduce bleeding but also helps to reduce pain.

Naproxen is also a good alternative to Mefenamic acid as this is a powerful anti-inflammatory.

People often ask what medications they can take alongside this treatment. It is fine to take Mefenamic acid tablets with paracetamol. However, you must not take any other NSAIDs, such as ibuprofen, aspirin, or naproxen. You can take Mefenamic acid with the contraceptive pill and many women will do this as this can also reduce the pain of a period.

The recommended dose is ONE tablet taken THREE times daily with or after food during your period.

The active ingredient in each tablet is: Mefenamic acid 500mg.

The inactive ingredients are:

Lactose Monohydrate, Pregelatinized Starch, Croscarmellose Sodium, Povidone, Microcrystalline cellulose, Colloidal Silicon Dioxide, Magnesium Stearate

Coating Material (Opadry Yellow): Hypromellose, Lactose Monohydrate, Titanium Dioxide (E171) Macrogol, Iron Oxide Yellow (E172) Talc, Iron Oxide Red (E172)

The most frequently reported side effects associated with mefenamic acid involve the gastrointestinal tract.

• Stomach pain
• Feeling sick
• Bowel problems, like constipation or diarrhoea

It can also cause

• Feeling dizzy and/or sleepy
• A ringing sound in your ears (tinnitus)
• Headache
• Heartburn

In rare circumstances, Mefenamic acid can cause more serious side effects. In this instance, you must seek immediate medical advice. These side effects include:

• Signs of intestinal bleeding - vomiting blood or dark particles resembling coffee grounds, black tarry stools, blood in stools.
• Signs of a serious allergic reaction - asthma, wheezing, shortness of breath, swelling of facial features, rashes, rapid heart rate, collapse.
• Stomach ulcer or perforation
• Worsening of bowel problems, e.g. ulcerative colitis or Crohn’s disease
• Kidney problems, showing symptoms of cloudy urine, more or less urine than usual, blood in urine, pain in the back and/or swelling, very rarely kidney failure
• Liver problems showing symptoms such as yellowing of the skin and eyes (jaundice), pale coloured stools, dark urine
• Blood disorders, showing symptoms such as unexplained/unusual bruising or bleeding, sore throat, mouth ulcers, fever, extreme paleness, weakness, exhaustion
• High blood pressure, heart failure, swelling due to fluid build-up, stroke

Before taking Mefenamic acid please take the time to read all the information included in the Patient Information Leaflet, which can be located in each box.

Do not take mefenamic acidif any of the following apply to you:

• You have (or have had 2 or more episodes of) a stomach ulcer, perforation or bleeding of the stomach
• You are allergic to NSAIDs, to any of the ingredients or to aspirin or other painkillers
• You have severe kidney, heart or liver failure
• You are taking aspirin with a daily dose above 75 mg
• You are pregnant or breastfeeding

Speak to a doctor or pharmacist before taking mefenamic acid if any of the following apply to you:

• You have liver or kidney problems
• You have stomach or bowel disorders including Crohn’s disease or a condition known as ulcerative colitis
• You have Systemic Lupus Erythematosus (SLE)
• You have previously had or are at risk of heart problems, high blood pressure or stroke.

You should not take mefenamic acid if you are taking any of the following medicines. If you are unsure if Mefenamic acid is the right medication for you speak to a doctor or pharmacist for advice.

• Anti-coagulants - aspirin/acetylsalicylic acid, warfarin, ticlopidine
• Medicines that reduce high blood pressure - captopril, atenolol, losartan.
• You are taking two or more NSAID painkillers, including cyclooxygenase-2 selective inhibitors
• Antidepressants called selective-serotonin reuptake inhibitors (SSRIs) - fluoxetine
• Corticosteroids
• Methotrexate
• Cardiac glycosides - digoxin
• Ciclosporin and tacrolimus
• Mifepristone (NSAIDs should not be used for 12 days after mifepristone)
• Lithium
• Zidovudine
• Quinolone antibiotics - ciprofloxacin