Meclofenamic acid

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Meclofenamic acid

Meclofenamic acid is a non-steroidal anti-inflammatory drug (NSAID) with antipyretic, anti-inflammatory and analgesic activities. It is used for treating mild to moderate pain of primary dysmenorrhea, idiopathic heavy menstrual blood loss, acute and chronic rheumatoid arthritis and osteoarthritis. It works by preventing prostaglandins from being produced by the injured tissue. 

Introduction

Meclofenamic acid is a non-steroidal anti-inflammatory drug (NSAID) with antipyretic, anti-inflammatory and analgesic activities. It is used for treating mild to moderate pain of primary dysmenorrhea, idiopathic heavy menstrual blood loss, acute and chronic rheumatoid arthritis and osteoarthritis. It works by preventing prostaglandins from being produced by the injured tissue.

Pharmacological class: NSAID

Indications

  • Primary dysmenorrhea
  • Rheumatoid arthritis
  • Menstrual cramps
  • Osteoarthritis

Pharamcological Action

The mode of action of meclofenamic acid, like other NSAIDS is not known. However, anti-inflammatory effects of this drug may result from the peripheral inhibition of prostaglandin synthesis secondary to inhibition of the enzyme cyclooxygenase. Prostaglandins sensitize pain receptors and their inhibition is thought to be responsible for the analgesic effects of meclofenamic acid. Unlike other NSAIDs, it appears to antagonize certain effects of existing prostaglandins through competition for prostaglandin binding sites.

Dosage

Mild to Moderate Pain: 50 mg every 4 to 6 hours

Primary dysmenorrhea: 100 mg 3 times a day, for up to 6 days

Rheumatoid arthritis & Osteoarthritis: 200 to 400 mg/day, administered in 3 or 4 equal doses.

Pharmacokinetics

Meclofenamic acid is completely bioavailable from capsules relative to an oral suspension dosage form. Maximum meclofenamic acid plasma concentrations are achieved in 0.5-2 h following doses of capsules. Meclofenamic acid is extensively metabolized. One of the metabolites, metabolite 1, is approximately 20% as active as the parent compound in inhibiting cyclooxygenase activity in vitro. This metabolite accumulates in plasma during repeated dosing.

Contraindications

  • Contraindicated in patients who are hypersensitive to meclofenamic acid.
  • Contraindicated in those patients who develop symptoms of bronchospasm, allergic rhinitis, or utricaria as cross reactivity with NSAIDs.

Drug Interactions

  • Concomitant use of meclofenamic acid and warfarin causes prolongation of prothrombin time.
  • Concurrent administration of aspirin and meclofenamic acid may lower its plasma levels.
  • Using edoxaban with meclofenamic acid may increase the risk of bleeding.
  • Meclofenamic acid may increase blood levels and side effects of methotrexate
  • Meclofenamate when combined with tacrolimus can increase the risk of kidney problems.

Side effects

Common (affecting between 1 in10 to 1 in 100)

  • Bloody, black or stools
  • Bloody urine
  • Decreased urine frequency or amount
  • Heartburn
  • Increased bleeding time
  • Hypertension
  • Increased thirst
  • Indigestion
  • Itching skin
  • Appetite loss
  • Lower back pain
  • Nausea
  • Pale skin

Uncommon (affecting 1 in 100 to 1 in 1000)

  • Bleeding gums
  • Blood in vomit
  • Blurred vision
  • Burning feel in the chest or stomach
  • Chest pain
  • Clay-colored stools
  • Cloudy urine
  • Confusion

Very Rare (affecting less than 1 in 10,000)

  • Skin blistering, peeling, or loosening
  • Change in consciousness
  • Chest discomfort
  • Vomiting
  • Skin cracks
  • Diarrhea
  • Dizziness or lightheadedness
  • Fever with or without chills
  • Flushed, dry skin
  • Fruit-like breath odor

Precautions

  • Avoid in patients who are allergic to meclofenamic acid.
  • Avoid in patients with asthma or frequent stuffed or runny nose or nasal polyps swelling of the hands, feet, ankles, or lower legs.
  • Avoid in patients with liver or kidney disease.
  • Avoid use in pregnant or breastfeeding women.

Clinic Evidence

  • In a study, the therapeutic efficacy of sodium meclofenamate/meclofenamic acid (300 mg per day) was compared with aspirin (3.6 g per day) and placebo in 317 patients with active rheumatoid arthritis. Analyses of measures of tenderness, total joint involvement, duration of morning stiffness, and patient condition and global improvement revealed that the therapeutic effectiveness of 300 mg sodium meclofenamate daily and 3.6 g aspirin daily were equivalent and significantly superior to that of placebo. Sodium meclofenamate showed good control of disease activity and was generally well tolerated in the treatment of rheumatoid arthritis.1
  • Eighteen patients participated in a double-blind, placebo-controlled, single-dose, crossover study of meclofenamate sodium/meclofenamic acid in women with primary dysmenorrhea. Improvements in pain intensity and pain relief were observed at 45 minutes and reached statistical significance at and beyond 1 hour 45 minutes after meclofenamic acid.2

References

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