Mefenamic Acid

Products

Mefenamic acid is commercially available in the form of film-coated tablets, capsules, suppositories, and oral suspension. The drug has been approved in many countries since 1965. In addition to the original Ponstan, various generics are available. In many countries, the drug is known to both specialists and the general public and is frequently taken. In Germany, however, no drugs containing the active ingredient are registered.

Structure and properties

Mefenamic acid (C15H15NO2, Mr = 241.3 g/mol) exists as a white, odorless, microcrystalline powder and is practically insoluble in water. It is a derivative of anthranilic acid and belongs to the fenamates.

Effects

Mefenamic acid (ATC M01AG01) has analgesic, antipyretic, and anti-inflammatory properties. It has a short half-life of about two hours. The effects are due to inhibition of prostaglandin synthesis by inhibition of cyclooxygenase.

Indications

For the treatment of acute and chronic pain of various causes and for the reduction of fever.

Dosage

According to the drug label. Adults usually take 500 mg three to a maximum of four times daily during a meal. The maximum daily dose is 2000 mg. In children, the dosage is based on body weight.

Contraindications

  • Hypersensitivity
  • Bronchospasm, hives, or allergy-like symptoms after taking ASA or other NSAIDs
  • Third trimester of pregnancy
  • Lactation period
  • Active gastric and/or intestinal ulcers
  • Gastrointestinal bleeding
  • Inflammatory bowel disease
  • Severe liver dysfunction
  • Severe renal insufficiency
  • Severe heart failure
  • Treatment of postoperative pain after coronary bypass surgery / use of a heartlung machine.

For complete precautions, see the drug label.

Adverse effects

The most common possible adverse effects include digestive disturbances such as stomach pain, nausea, and vomiting. Other common side effects include lack of appetite, stomach burning, flatulence, and constipation. Like all NSAIDs, mefenamic acid can rarely cause serious side effects. These include blood count changes such as agranulocytosis, stomach or intestinal ulcers, cardiovascular disease, anaphylaxis, and severe skin and kidney disease.