MEFENAMIC ACID

Category – Analgesic

Introduction:

Mefenamic Acid is a nonsteroidal anti-inflammatory drug (NSAID).It has analgesic as well as antipyretic properties, but it is mainly used for treatment of pain.

Mefenamic acid is widely used to treat mild to moderate pain including headache, dental pain, dysmenorrhea, rheumatoid arthritis, osteoarthritis and other joint disorders.

Mefenamic acid is administered most commonly through oral route but in some conditions, it can be given intravenously(injection).

Mefenamic acid is rapidly absorbed after oral administration.

Uses:

Mefenamic acid is used to relieve moderate and severe pain according to the dose of drug.

Mefenamic acid can be used in the following conditions:-

• Menstrual cramps

• Body pain

• Muscle aches

• Dental pain

• Headache

• Dysmenorrhea,

• Rheumatoid arthritis,

• Osteoarthritis

• Other joint disorders.

How to Consume:

Mefenamic acid should be taken as per prescribed by the doctor. The dosage form and quantity of the drug might be different for every pain and inflammation.

It should be taken after food at intervals of 6 hours up to 1 week depending upon the severity of the pain or inflammation.

For the relief of acute pain in adults and adolescents more than 14 years of age, the recommended dose is 500 mg as an initial dose followed by 250 mg every 6 hours as needed, usually it should not be exceed more than one week.

Keep this medicine in a tightly closed container, and out of reach of children. Store it at room temperature and away from heat and moisture.

Duration between two dose:

Mefenamic acid is normally taken at interval of 6 hours after food or as per prescribed by the doctor.

Side effects:

Some common side effects can be seen after taking Mefenamic acid

• Bloody urine

• Decreased frequency or amount of urine

• Heartburn

• Increased bleeding time

• Increased blood pressure

• Increased thirst

• Indigestion

• Itching, skin rash

• Loss of appetite

• Lower back or side pain

• Pale skin

• Severe stomach pain, cramping, or burning

• Stomach bloating

• Swelling of the face, fingers, feet, or lower legs

• Trouble breathing

• Unusual tiredness or weakness

• Vomiting

• Weight gain

• Weight loss

Drug Mechanism:

Pharmacokinetics-

Mefenamic Acid is well absorbed after oral administration, and it has a fast onset of action. It is metabolized in the liver and excreted primarily through the kidneys. The half-life of Mefenamic Acid ranges between 2-4 hours.

Mefenamic Acid is administered orally in the form of capsules or tablets. It is typically taken with food to reduce the risk of stomach upset.

Mefenamic Acid has a bioavailability of 90%, which means that 90% of the drug is absorbed and available for use in the body. Food does not significantly affect the bioavailability of Mefenamic Acid.

Mefenamic Acid is distributed throughout the body, and it has a high degree of protein binding.

Mefenamic Acid is extensively metabolized in the liver by cytochrome P450 enzymes. The primary metabolite is 3-OH-mefenamic acid, which is then conjugated and excreted in the urine.

Mefenamic Acid and its metabolites are excreted primarily through the kidneys. A small amount of the drug is excreted in the feces.

Pharmacodynamics-

Like other NSAIDs, mefenamic acid is a cyclo-oxygenase ( Cox- 1 and-2) inhibits and blocks the production of intracellular prostaglandins that are important in pain anti-seditious pathways. Mefenamic acid has analgesic as well as antipyretic and anti-inflammatory properties, but is used largely for treatment of pain.

Safety Measures:

• Do check with your doctor if you are having chest pain or discomfort, nausea, vomiting or discomfort in arms, jaw, back or neck after taking the medicine.

• To avoid smoking and drinking after taking the medicine.

• To avoid taking the medicine for long term.

• If you miss the dosage, skip it, don’t double it.

• Do not stop taking medication even if you feel better, stopping it sooner will cause the infection to return and more difficult to treat.

• For Stomach- The medicine may cause bleeding in stomach or intestine, it most likely occurs if the person had stomach ulcer in past.

• For Heart- The medicine may raise a risk of having heart attack or stroke, this affects to people with past heart disease.

When to see a doctor:

• Chest pain

• Discomfort

• Nausea

• Vomiting

• Trouble breathing

• Slurred speech

• Weakness

• Stomach bleeding

• Intestine bleeding

• Discomfort in arms, jaw, back or neck

If conditions from this occur you should immediately visit the doctor or it can be dangerous for your health if not cured as soon as possible.

Allergic reactions:

This medicine can cause a severe allergic reaction called anaphylaxis or Stevens Johnson Syndrome.

Available Dosage Form-

Form:

1. Oral Tablet (Capsule)

Strengths: 250mg, 500mg

2. Intravenous (Injection)

Strengths: 100mg/5ml

3. Oral suspension

Strength: 100mg

Child Dosage-

Ages below 14yrs

Mefenamic acid is not recommended for children’s of age below 14yrs

The use and dose of the medication for children should be taken on the advice of the doctor.

Adult Dosage-

Ages 14yrs and above5

Dosage for adults over 14 years old is 500mg at first day , then 250mg every 6 hours as needed for 2 to 3 days.

Important Note:

• This medication usually should not be taken for more than 7 days at a time.

• If you use this medicine for painful periods, take your first dose right at the start of your period or pain.

• This medication may raise your blood pressure. Do check your blood pressure regularly and tell your doctor if the BP is high.

• Do not lie down for a minimum of 10 minutes after taking this medicine.

• In case of stomach problems, take this medication with food or milk.

• Do not take mefenamic acid with antacids unless instructed to do so by your doctor.

• Some antacids may affect the amount of mefenamic acid absorbed by the body.

• Do not increase your dose or use it more frequently or for longer than prescribed.

• Follow the complete treatment prescribed by the physician, do not skip a dose in the treatment.

Various brands:

Mefwell-250

Meftal-500

Mefix-500

Mefac-250,500

Mefanorm (100mg/5ml)

Meftal-500

References:

1. Indian Pharmacopoeia (IP)

2. https://www.ncbi.nlm.nih.gov

3. https://www.researchgate.net

4. https://medlineplus.gov