Mefenamic acid

mefenamic acid

Treatment options

Buy mefenamic acid safely, securely and easily in a few simple steps. Start a consultation today to check your eligibility with a prescribing clinician, at no cost to you.

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This content is intended for UK audiences only

mefenamic acid
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Manufactured by various MHRA-approved generic manufacturers


Only £ per Pack

Dispensed in the UK
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Delivered securely by Royal Mail
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What to do if you missed your mefenamic acid dose

Report suspected side effects or adverse reactions to the Medicines and Healthcare Products Regulatory Agency (MHRA) using the Yellow Card Reporting system that covers medicines, vaccines, e-cigarettes and medical device incidents.

Learn more about reporting side effects

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About mefenamic acid

Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) used for the treatment of mild to moderate pain. It is also used to treat menstrual cramps. Mefenamic acid blocks the production of prostaglandins, which reduces contraction of the uterus and pain during your period. It also reduces blood loss.

NowPatient offers mefenamic acid as a treatment for period pain only, following an online consultation with a prescribing clinician.

Key facts of mefenamic acid

  • For the treatment of period pain
  • Mefenamic acid takes about 30 – 60 minutes to work
  • Mefenamic acid has some common side effects which include stomach pain and loss of appetite
  • It can be dangerous if you take mefenamic acid with certain medications. If you’re not sure if it is safe, discuss this with the prescribing clinician

Who is mefenamic acid not suitable for?

Mefenamic acid may not be suitable for some people. To make sure it’s safe for you, speak to the prescribing clinician before taking mefenamic acid if you:

  • Are allergic to the active ingredient mefenamic acid
  • Have had 2 or more episodes of a stomach ulcer, perforation or bleeding of the stomach
  • Have severe kidney disease, heart or liver disease
  • Take aspirin with a daily dose over 75 mg
  • Have Crohn’s disease or ulcerative colitis
  • Have Systemic Lupus Erythematosus (SLE)
  • Are at risk of heart problems, high blood pressure or stroke

How and where to get mefenamic acid?

Mefenamic acid is available with a prescription only. It is not available over the counter at a pharmacy.

NowPatient does not allow customers to buy mefenamic acid directly. Our service is certified, safe and effective, and we only ever treat conditions. If you book a consultation with a prescribing clinician for the treatment of period pain, you can discuss if mefenamic acid is a suitable treatment option for you.

At the end of the consultation, the clinician will decide if a treatment plan is suitable for you. If it is, the clinician will issue you with a prescription which can then be ordered, paid for and delivered directly to your chosen address by NowPatient.

Dosage and strength for mefenamic acid for period pain

Mefenamic acid is available as tablets and capsules when used for period pain. It is available in strengths ranging from 250 to 500 mg.

Information about how to take mefenamic acid for period pain

Mefenamic acid should be taken as 500mg three times a day with or after food during your period.

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, skip the missed dose and take your next dose at the regular time. Speak to a healthcare professional if you need further medical advice.

What happens if you take too much mefenamic acid?

If you take more than prescribed, then it can lead to some unpleasant side effects. You should talk to your doctor or reach out to one of our prescribing clinicians, if you have taken too much mefenamic acid and you experience any of the following side effects:

What are the side effects of mefenamic acid?

Side effects of mefenamic acid are split into common and serious.

Common side effects include:

  • Stomach pain
  • Loss of appetite
  • Constipation or diarrhoea
  • Dizziness or drowsiness
  • Headache
  • Indigestion
  • Heartburn

Serious side effects include:

  • Intestinal bleeding – vomiting blood or vomit that looks like coffee grounds, black tarry stools
  • Stomach ulcers
  • Worsening of ulcerative colitis or Crohn’s disease
  • Kidney problems
  • Liver problems such as yellowing of the skin, pale coloured stools, dark urine
  • High blood pressure, heart failure

If you experience any serious side effects, you should contact NHS 111.

If you experience a serious allergic reaction with the signs shown below you should contact emergency services on 999.

  • Your lips, mouth, throat or tongue suddenly become swollen
  • You’re breathing very fast or shortness of breath
  • Your throat feels tight or you’re struggling to swallow
  • Your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
  • You suddenly become very confused, drowsy or dizzy
  • Someone faints and cannot be woken up

Always report adverse effects to the MHRA yellow card reporting system. You can read more about this here How and where do I report side effects of my medication? – NowPatient

Information about taking mefenamic acid at the same time as other medications or herbal supplements

There is not enough evidence to suggest there are any drug interactions between herbal supplements and mefenamic acid. In any event, you should let your prescribing clinician know if you are taking any herbal supplements.

  • Anti-coagulants such as warfarin
  • Medicines for high blood pressure – captopril, atenolol, losartan
  • Two or more NSAID painkillers, including cyclooxygenase-2 selective inhibitors
  • Selective-serotonin reuptake inhibitors (SSRIs)
  • Corticosteroids
  • Methotrexate
  • Diuretics
  • Ciclosporin
  • Lithium
  • Zidovudine

Can mefenamic acid taken for period pain be taken long term?

Mefenamic acid is approved to treat pain for no longer than seven days. It is approved to treat menstrual cramps for no more than 2 to 3 days.

Is there a herbal mefenamic acid?

No. Herbal mefenamic acid does not exist. If you have been marketed such a formulation, it may be fake.

Can women use mefenamic acid?

Women can take mefenamic acid for the treatment of period pain. However, mefenamic acid passes into breast milk. Speak to your doctor before breast-feeding.

Should I avoid any particular food or drink when taking mefenamic acid?

You can eat and drink normally when taking mefenamic acid.

What lifestyle changes can I make to help me with period pain?

You can take paracetamol if you period pain is particularly bad, at the same time as you take mefenamic acid. You can also use heat pads on the abdomen area and lower back.

Alternatives to mefenamic acid

Alternatives for the treatment of period pain include other NSAIDs such as ibuprofen, naproxen, diclofenac, or celecoxib.


Medical Disclaimer

NowPatient has taken all reasonable steps to ensure that all material is factually accurate, complete, and current. However, the knowledge and experience of a qualified healthcare professional should always be sought after instead of using the information on this page. Before taking any drug, you should always speak to your doctor or another qualified healthcare provider.

The information provided here about medications is subject to change and is not meant to include all uses, precautions, warnings, directions, drug interactions, allergic reactions, or negative effects. The absence of warnings or other information for a particular medication does not imply that the medication or medication combination is appropriate for all patients or for all possible purposes.

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