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Mefenamic Acid from £49.95

Mefenamic Acid

Mefenamic acid is a treatment for mild-to-moderate pain, including menstrual pain (period pain). Additionally, it may be used to reduce blood loss during menstruation.

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What is Mefenamic acid?

Mefenamic acid is used for the treatment of mild-to-moderate pain arising from various sources, including painful menstruation (dysmenorrhoea) often with abdominal cramps. Additionally, it may be used to reduce blood loss during menstruation when bleeding is abnormally heavy (menorrhagia), particularly when an intrauterine device is present.

Mefenamic acid is non-steroidal anti-inflammatory drug (NSAID) and so has analgesic, antipyretic and anti-inflammatory properties, relieving pain, fever and inflammation, respectively. It works by binding to receptors known as cyclooxygenase-1 and -2, which inhibits the enzyme that facilitates the production of the hormone prostaglandin. Prostaglandin plays a major role in inflammation and pain, so by inhibiting its production, the symptoms of pain are reduced.

How to use

Mefenamic acid may be provided as a 250 mg capsule, when two capsules are taken three times a day, or as a 500 mg tablet, when one tablet is taken three times a day. When given as pain relief to children, those younger than 12 years should be given the Suspension (50mg/5ml) of Mefenamic Acid. Swallow the capsules/tablets whole with a glass of water, after or with food. With period pain, this medicine is started when the pain starts; with heavy bleeding, the medicine is started when the bleeding becomes excessive. Take Mefenamic acid for the shortest time possible, that being only for as long as you need to control your symptoms. Your doctor will tell you exactly what to do and how long to continue taking the medicine. You may be regularly monitored depending on how long you take it and your other health conditions.

Who can use Mefenamic acid?

People of all ages can take Mefenamic acid. However, caution is advised with older people who are at an increased risk of side effects, particularly gastrointestinal bleeding. Mefenamic acid is not advised in women who wish to conceive, or are pregnant or breast feeing because it may lower fertility or adversely affect the baby and mother.

This medicine should not be taken by people who are hypersensitive to the active ingredient Mefenamic acid or the other ingredients in the product or to other NSAIDs. Since Mefenamic acid is an NSAID, it should not be used by people who have/have had gastrointestinal bleeding or ulcers. Neither should it be taken by people with inflammatory bowel disease, liver or kidney failure, heart failure, or galactose/lactose intolerance, or for post-surgical pain following a coronary artery bypass graft. Also, you must be careful when taking Mefenamic acid if you have/have had asthma, impaired renal or liver function, heart problems (e.g., congestive heart failure, ischaemic heart disease, or cerebrovascular disease), systemic lupus erythematosus, and epilepsy. Caution should be taken when treating patients at increased risk of gastrointestinal disorders or taking medicines that may cause gastrointestinal side effects.

Mefenamic acid interacts with other medicines and so you must notify your doctor to all your medicines. Specifically, these include medications increasing the risk of bleeding, such as corticosteroids, other NSAIDs (including aspirin), anticoagulants (warfarin), anti-platelet agents (aspirin), and antidepressants (selective serotonin reuptake inhibitors). Additionally, your doctor will want to know your medicines that work by affecting the kidneys (e.g., diuretics, antihypertensives, and antibiotics), suppress the immune system (e.g., cyclosporin, methotrexate, tacrolimus), or used to treat conditions involving mental health (lithium), the heart/blood pressure (e.g., cardiac glycosides, angiotensin converting enzyme inhibitors, angiotensin II receptor blockers), diabetes (sulfonylurea), gout (probenecid), and HIV/AIDS (zidovudine).

Side Effects

Most frequently, people report side effects involving the gastrointestinal tract, such as nausea, vomiting, upset stomach, heartburn, constipation, and diarrhoea.

If you experience any side effects that progressively worsen or persist, seek medical attention. Rarely, serious side effects occur, when the medicine must be stopped and medical help sought immediately. These may comprise the following signs and symptoms: allergic/ hypersensitivity reactions consisting of generalised swelling or the swelling of the face, tongue or throat; respiratory symptoms (e.g., laboured breathing, asthma); and/or skin reactions (e.g., rash, itching, swelling, hives); dizziness, drowsiness, headache, fatigue, fever; heart and blood vessel disorders including hypertension, palpitations, heart failure, myocardial infarction or stroke; red and white blood cell disorders with increased risk of bleeding and infection; aseptic meningitis (especially in patients with autoimmune disorders, with symptoms such as stiff neck, headache, and nausea); mental health issues such as depression, nervousness, confusion, hallucinations; liver and gallbladder problems (seen as gastrointestinal upset, change in colour and amount of urine, yellowish eyes and skin); and/or visual disturbances and ear disorders (pain, tinnitus).

Reviewed by: Dr Loraine Haslam MBBS, DRCOG, DFSRH, LoC SDI, LoC IUT, MRCGP
GMC registration number: 4524038
Date: 11 August 2022
Next review: 10 August 2024
All UK registered doctors can have their registration checked on
The Medical Register at the GMC website.

Information Leaflet

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