Mefenamic Acid 500mg Tablets contain mefenamic acid, a non-steroidal anti-inflammatory drug (NSAID) used to relieve pain and reduce inflammation.

Mefenamic acid works by reducing the production of prostaglandins, substances involved in pain, inflammation and menstrual cramps.

It may be prescribed for several conditions, including:

  • Period pain (dysmenorrhoea): Helps relieve painful menstrual cramps and associated discomfort.
  • Heavy menstrual bleeding: May help reduce menstrual blood loss in certain circumstances, after other causes have been assessed.
  • Muscle and joint pain: May provide relief from selected painful musculoskeletal conditions.
  • Osteoarthritis: May help relieve joint pain and inflammation.
  • Rheumatoid arthritis: May help manage pain and stiffness as part of a wider treatment plan.
  • Dental and post-traumatic pain: May be prescribed for certain short-term painful conditions.

Although mefenamic acid has several licensed uses, it is particularly relevant to the management of period pain. It is not suitable for every type of pain or every patient.

Mefenamic Acid 500mg Tablets are prescription-only medicines. Treatment through Pharmulous is subject to a clinical assessment by an authorised prescriber.

Active ingredient:

Each tablet contains 500mg of mefenamic acid.

Mefenamic acid belongs to the NSAID group of medicines and has both pain-relieving and anti-inflammatory properties.

Other ingredients:

These depend on the manufacturer. Some formulations contain lactose or colourings. Check the patient information leaflet supplied with your medicine if you have allergies or intolerances.

The usual licensed adult dose for many UK 500mg tablet formulations is:

Take one tablet (500mg) three times daily, with or after food, as prescribed.

For period pain, treatment is generally started when menstrual pain begins and continued for the duration recommended by the prescriber.

For heavy menstrual bleeding, treatment is generally started on the first day of excessive bleeding, following medical assessment and the prescribed treatment plan.

How to Take Mefenamic Acid

  • Follow the dosage instructions on your prescription label.
  • Take tablets with or after food.
  • Swallow the tablet with water.
  • Use the lowest effective dose for the shortest necessary duration.
  • Do not exceed the dose prescribed.
  • Do not take mefenamic acid alongside naproxen, ibuprofen, diclofenac or other NSAIDs unless specifically instructed by a clinician.
  • Do not take a double dose to make up for a missed dose.

Mefenamic acid should not be used continuously or repeatedly without appropriate medical review.

Possible Side Effects

These include:

  • Diarrhoea
  • Nausea or vomiting
  • Indigestion or heartburn
  • Stomach pain
  • Headache
  • Dizziness
  • Drowsiness
  • Skin rash

Diarrhoea is a recognised side effect of mefenamic acid. If it develops, stop taking the medicine and seek advice from a healthcare professional.

Serious Side Effects

Stop taking mefenamic acid and seek urgent medical advice if you experience:

  • Black, tar-like stools
  • Vomiting blood or material resembling coffee grounds
  • Severe or persistent abdominal pain
  • Unexplained bleeding or bruising
  • A significant reduction in urination
  • Yellowing of the skin or eyes
  • Severe skin reactions, including blistering or peeling

Call 999 if you experience difficulty breathing, swelling of the face or throat, chest pain or symptoms of a stroke.

NSAIDs can increase the risk of gastrointestinal bleeding, kidney problems and certain cardiovascular events, particularly with higher doses or prolonged use.

Storage Instructions

  • Keep out of the sight and reach of children.
  • Store according to the instructions on the original packaging.
  • Keep tablets in their original packaging.
  • Do not use after the expiry date.
  • Do not use tablets if the packaging is damaged.
  • Return unwanted or expired medicines to a pharmacy for safe disposal.
Frequently asked questions

  • What is mefenamic acid?

    Mefenamic acid is a prescription NSAID used to relieve pain and inflammation, including pain associated with menstruation and certain musculoskeletal conditions.

  • What is mefenamic acid used for?

    It may be prescribed for period pain, heavy menstrual bleeding, arthritis-related discomfort, muscle pain and certain other painful conditions.

  • Is mefenamic acid a painkiller?

    Yes. It is a pain-relieving medicine with anti-inflammatory properties.

  • Is mefenamic acid an anti-inflammatory?

    Yes. It belongs to the non-steroidal anti-inflammatory drug group.

  • Can mefenamic acid help with period pain?

    Yes. It can help relieve menstrual cramps. by reducing prostaglandin production.

  • Can mefenamic acid reduce heavy periods?

    Mefenamic acid may reduce menstrual blood loss in some patients. Heavy bleeding should be assessed to identify possible underlying causes.

  • Does mefenamic acid stop periods?

    No. It is not intended to stop menstruation completely.

  • Should I take mefenamic acid with food?

    Yes. Taking it with or after food is recommended to help reduce stomach irritation.

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