Mefenamic acid

2D structure of Mefenamic Acid

Mefenamic acid is a non-steroidal anti-inflammatory drug (NSAID) used to treat mild to moderate pain, including menstrual pain, and is sometimes used to treat arthritis. It is part of the anthranilic acid derivatives class of NSAIDs, also known as fenamates.

Chemical Structure and Properties

Mefenamic acid is chemically known as 2-[(2,3-dimethylphenyl)amino]benzoic acid. It is a white crystalline powder with a melting point of approximately 230°C. The molecular formula is C₁₅H₁₅NO₂, and it has a molecular weight of 241.29 g/mol.

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3D structure of Mefenamic Acid

The structure of mefenamic acid consists of a benzoic acid moiety linked to an aniline group, which is substituted with two methyl groups. This structure is responsible for its pharmacological activity as an NSAID.

Mechanism of Action

Mefenamic acid works by inhibiting the cyclooxygenase (COX) enzymes, COX-1 and COX-2, which are involved in the synthesis of prostaglandins. Prostaglandins are lipid compounds that play a key role in inflammation and pain. By reducing the production of prostaglandins, mefenamic acid alleviates pain and reduces inflammation.

Pharmacokinetics

After oral administration, mefenamic acid is absorbed from the gastrointestinal tract. It is extensively bound to plasma proteins, primarily albumin. The drug is metabolized in the liver to form several metabolites, which are then excreted in the urine.

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Metabolites of Mefenamic Acid

The half-life of mefenamic acid is approximately 2 to 4 hours, and it is usually administered every 6 hours to maintain effective plasma concentrations.

Clinical Uses

Mefenamic acid is primarily used for the treatment of:

• Dysmenorrhea (menstrual pain)
• Mild to moderate pain from various causes
• Inflammatory conditions such as osteoarthritis and rheumatoid arthritis

Side Effects

Common side effects of mefenamic acid include:

• Gastrointestinal disturbances such as nausea, vomiting, diarrhea, and abdominal pain
• Headache
• Dizziness
• Skin rash

Serious side effects may include gastrointestinal bleeding, ulceration, and renal impairment.

Contraindications

Mefenamic acid should not be used in individuals with:

• Known hypersensitivity to mefenamic acid or other NSAIDs
• Active peptic ulcer disease
• Severe renal or hepatic impairment
• History of asthma attacks or allergic reactions after taking aspirin or other NSAIDs

Related Pages

• Non-steroidal anti-inflammatory drug
• Prostaglandin
• Cyclooxygenase
• Pain management