Acidum Mefenamicum

Acidum Mefenamicum Uses, Dosage, Side Effects, Food Interaction and all others data.

Acidum Mefenamicum, an anthranilic acid derivative, is a prototypical NSAID. It reversibly inhibits the cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2) enzymes, thus resulting in reduced synthesis of prostaglandin precursors. It has analgesic and antipyretic properties with minor anti-inflammatory activity.

Acidum Mefenamicum, an anthranilic acid derivative, is a member of the fenamate group of nonsteroidal anti-inflammatory drugs (NSAIDs). It exhibits anti-inflammatory, analgesic, and antipyretic activities. Similar to other NSAIDs, mefenamic acid inhibits prostaglandin synthetase.

Trade Name Acidum Mefenamicum
Generic Mefenamic acid
Mefenamic acid Other Names Acide méfénamique, ácido mefenámico, Acidum mefenamicum, Mefenamic acid, Mefenaminsäure
Formula C15H15NO2
Weight Average: 241.2851
Monoisotopic: 241.110278729
Protein binding


Groups Approved
Therapeutic Class Drugs for Osteoarthritis, Drugs used for Rheumatoid Arthritis, Non-steroidal Anti-inflammatory Drugs (NSAIDs)
Available Country
Last Updated: September 19, 2023 at 7:00 am
Acidum Mefenamicum
Acidum Mefenamicum


Acidum Mefenamicum is used in mild to moderate pain including headache, dental pain, postoperative and postpartum pain, dysmenorrhoea, menorrhagia, in musculoskeletal and joint disorders such as osteoarthritis and rheumatoid arthritis; and in children with fever and juvenile idiopathic arthritis.

Acidum Mefenamicum is also used to associated treatment for these conditions: Mild pain, Primary Dysmenorrhoea, Gastrointestinal cramps, Moderate Pain

How Acidum Mefenamicum works

Acidum Mefenamicum binds the prostaglandin synthetase receptors COX-1 and COX-2, inhibiting the action of prostaglandin synthetase. As these receptors have a role as a major mediator of inflammation and/or a role for prostanoid signaling in activity-dependent plasticity, the symptoms of pain are temporarily reduced.


Acidum Mefenamicum dosage

As with other NSAIDs, the lowest dose should be sought for each patient. Therefore, after observing the response to initial therapy with Acidum Mefenamicum, the dose and frequency should be adjusted to suit an individual patient's needs.Administration is by the oral route, preferably with food.

  • Adult: A 500 mg dose should be given to adults up to three times (1.5 g total) per day.
  • Infants over 6 months: 25 mg/kg of body weight daily in divided doses for not longer than 7 days.

Side Effects

In patients taking Acidum Mefenamicum or other NSAIDs, the most frequently reported adverse experiences include : abdominal pain, constipation, diarrhoea, dyspepsia, flatulence, gross bleeding/perforation, heartburn, nausea, GI ulcers, vomiting, abnormal renal function, anaemia, dizziness, oedema, elevated liver enzymes, headache, increased bleeding time, pruritus, rash and tinnitus.


Oral, rat LD50: 740 mg/kg. Symptoms of overdose may include severe stomach pain, coffee ground-like vomit, dark stool, ringing in the ears, change in amount of urine, unusually fast or slow heartbeat, muscle weakness, slow or shallow breathing, confusion, severe headache or loss of consciousness.


NSAIDs should be prescribed with extreme caution in those with a prior history of ulcer disease or gastrointestinal bleeding. To minimise the potential risk for an adverse GI event, the lowest effective dose should be used for the shortest possible duration. In cases with pre-existing advanced kidney disease, treatment with Acidum Mefenamicum is not recommended.


Concomitant use with CYP2C9 isoenzyme inhibitors may alter safety and efficacy of mefenamic acid. May enhance methotrexate toxicity. Reduced BP response to ACE inhibitors or angiotensin II receptor antagonists. Increased risk of serious GI events with aspirin. May reduce the natriuretic effects of furosemide or thiazide diuretics. Reduced renal lithium clearance and elevated plasma lithium levels. May enhance anticoagulant effect of warfarin.

Food Interaction

  • Avoid alcohol.
  • Take with food.

Volume of Distribution

  • 1.06 L/kg [Normal Healthy Adults (18-45 yr)]

Elimination Route

Acidum Mefenamicum is rapidly absorbed after oral administration.

Half Life

2 hours


  • Oral cl=21.23 L/hr [Healthy adults (18-45 yrs)]

Elimination Route

The fecal route of elimination accounts for up to 20% of the dose, mainly in the form of unconjugated 3-carboxymefenamic acid.3 The elimination half-life of mefenamic acid is approximately two hours. Acidum Mefenamicum, its metabolites and conjugates are primarily excreted by the kidneys. Both renal and hepatic excretion are significant pathways of elimination.

Pregnancy & Breastfeeding use

Pregnancy: In late pregnancy, as with other NSAIDs, Acidum Mefenamicum should be avoided because it may cause premature closure of the ductus arteriosus. In general there are no adequate and well controlled studies in pregnant women. Acidum Mefenamicum should be used during pregnancy only if the potential benefit justifies the potential risk to the foetus. Rated as Pregnancy Category C.

Lactation: Trace amounts of Acidum Mefenamicum may be present in breast milk. Taking into account the importance of the drug to the mother , decision should be made whether to discontinue nursing or to discontinue the drug.


Acidum Mefenamicum is contraindicated in patients with known hypersensitivity to Me Acidum Mefenamicum acid. Acidum Mefenamicum should not be given to patients who have experienced asthma, urticaria, or allergic type reactions after taking aspirin or other NSAIDs. Rarely fatal, anaphylactic like reactions to NSAIDs have been reported in such patients. Acidum Mefenamicum is contraindicated in patients with active ulceration or chronic inflammation of upper gastrointestinal tract and should not be used in patients with preexisting renal disease.

Acute Overdose

Symptoms: Headache, nausea, vomiting, epigastric pain, GI bleeding. Rarely, diarrhoea, disorientation, excitation, coma, drowsiness, tinnitus, fainting, and occasionally convulsions.

Management: Symptomatic and supportive treatment. In acute overdosage, empty the stomach immediately by inducing emesis or by gastric lavage followed by admin of activated charcoal.

Storage Condition

Store between 20-25° C.

Innovators Monograph

You find simplified version here Acidum Mefenamicum

Acidum Mefenamicum contains Mefenamic acid see full prescribing information from innovator Acidum Mefenamicum Monograph, Acidum Mefenamicum MSDS, Acidum Mefenamicum FDA label


What is Acidum Mefenamicum used for?

Acidum Mefenamicum is used short-term to treat mild to moderate pain in adults and children who are at least 14 years old.

How safe is Acidum Mefenamicum?

Acidum Mefenamicum may increase your risk of heart problems, including heart attack, stroke, heart failure, or blood clot. These conditions can be fatal. Your risk may increase if you already have heart disease or have taken the medication for a long period of time or at high doses.

How does Acidum Mefenamicum work?

Acidum Mefenamicum works by stopping the body's production of a substance that causes pain, fever, and inflammation.

What are the common side effects of Acidum Mefenamicum?

Common side effects of Acidum Mefenamicum are include:

  • diarrhea.
  • constipation.
  • gas or bloating.
  • headache.
  • dizziness.
  • nervousness.
  • ringing in the ears

Is Acidum Mefenamicum safe during pregnancy?

Use of Acidum Mefenamicum during pregnancy is not advised unless prescribed by a doctor, especially if you are 30 or more weeks pregnant.

Is Acidum Mefenamicum safe during breastfeeding?

Acidum Mefenamicum passes into breast milk and is not recommended for use while breastfeeding.

Can I drink alcohol with Acidum Mefenamicum?

Do not drink alcohol while taking Acidum Mefenamicum. Alcohol can increase your risk of stomach bleeding caused by Acidum Mefenamicum. Call your doctor at once if you have symptoms of bleeding in your stomach or intestines.

Can I drive after taking Acidum Mefenamicum?

Acidum Mefenamicum Tablets may cause drowsiness, fatigue, dizziness or may affect your vision. If you experience any of these symptoms, you should not drive or operate machinery, or perform any tasks which may require you to be alert.

When should be taken of Acidum Mefenamicum?

Acidum Mefenamicum is usually taken with food every 6 hours as needed for up to 1 week.

Is it safe to take Acidum Mefenamicum?

Acidum Mefenamicum should not be used for longer than 7 days.

How many times can I take Acidum Mefenamicum?

Acidum Mefenamicum take 250 mg every six hours as needed. You shouldn't take Acidum Mefenamicum for longer than three days.

How long does Acidum Mefenamicum take to work?

If you wait until the symptoms have worsened,Acidum Mefenamicum may not work as well. If you are using Acidum Mefenamicum for painful periods, take your first dose as soon as your period starts or pain begins. Usually, you will only need to take it for the first 2 to 3 days of your period.

How long does it take for Acidum Mefenamicum to kick in?

Acidum Mefenamicum takes between 2 - 4 hours to kick in and start easing your period pain. Each 500mg dose of Acidum Mefenamicum kills pain for up to 8 hours, so you may need to take it two or three times a day for all-day relief.

Can I take Acidum Mefenamicum for a long time?

Acidum Mefenamicum should not be used for longer than 7 days. Follow your doctor's dosing instructions very carefully. If you use Acidum Mefenamicum long-term, you may need frequent medical tests.Acidum Mefenamicum can cause unusual results with certain medical tests.

Who should not take Acidum Mefenamicum?

Acidum Mefenamicum can increase your risk of fatal heart attack or stroke. Do not use Acidum Mefenamicum just before or after heart bypass surgery .Acidum Mefenamicum may also cause stomach or intestinal bleeding, which can be fatal.

What happens if I miss a dose on Acidum Mefenamicum?

Take Acidum Mefenamicum as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happen if I take too much Acidum Mefenamicum?

If you take too much If you take too much Acidum Mefenamicum, you may experience: drowsiness, nausea,vomiting.

When can I stop taking Acidum Mefenamicum?

If you experience any of the following symptoms, stop taking Acidum Mefenamicum and call your doctor: stomach pain, heartburn, vomit that is bloody or looks like coffee grounds, blood in the stool, or black and tarry stools.

Can Acidum Mefenamicum affects my heart ?

Acidum Mefenamicum can increase your risk of fatal heart attack or stroke, especially if you use it long term or take high doses, or if you have heart disease.

*** Taking medicines without doctor's advice can cause long-term problems.