Diclofenac

A powerful anti-inflammatory painkiller explained with chemistry, biology, and clinical science.

What is Diclofenac?

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) widely used for the treatment of pain and inflammation. It is especially effective in conditions involving joint inflammation, muscle pain, and post-operative pain.

Because of its strong anti-inflammatory action, diclofenac is often preferred when pain is associated with swelling and tissue damage.

History & Development

Diclofenac was developed in the 1970s and quickly became popular due to its high potency compared to earlier NSAIDs. It is now available worldwide in oral, injectable, topical gel, and suppository forms.

Chemical Structure & Properties

• IUPAC name: 2-(2,6-dichloroanilino)phenylacetic acid
• Molecular formula: C₁₄H₁₁Cl₂NO₂
• Molar mass: 296.15 g/mol
• Functional groups: Carboxylic acid, aromatic rings, amine

The presence of chlorine atoms increases lipophilicity, helping diclofenac penetrate inflamed tissues effectively.

Mechanism of Action

Diclofenac inhibits cyclooxygenase enzymes (COX-1 and COX-2), with a preference for COX-2. This reduces the synthesis of prostaglandins responsible for pain, inflammation, and fever.

• ↓ Prostaglandins → reduced pain & swelling
• ↓ Inflammatory mediators → faster relief

Pharmacokinetics

• Absorption: Well absorbed orally
• First-pass metabolism: Significant
• Protein binding: >99%
• Metabolism: Liver (CYP2C9)
• Excretion: Urine and bile

Medical Uses

• Arthritis (rheumatoid & osteoarthritis)
• Muscle and joint pain
• Post-surgical pain
• Back pain
• Dental pain

Dosage Guidelines

Adults (oral): 50 mg 2–3 times daily

Maximum daily dose: 150 mg

⚠️ Use the lowest effective dose for the shortest duration.

Side Effects

• Stomach pain
• Indigestion
• Nausea
• Headache

Serious Risks & Warnings

• Gastric ulcers and bleeding
• Liver enzyme elevation
• Increased cardiovascular risk (long-term use)

Drug Interactions

• Other NSAIDs
• Blood thinners
• Antihypertensive drugs
• Alcohol

Diclofenac vs Ibuprofen

Diclofenac is generally more potent for inflammatory pain, while ibuprofen is safer for short-term mild pain.

Frequently Asked Questions

Is diclofenac safe? – Yes, when used correctly and short-term.

Is diclofenac stronger than ibuprofen? – Yes.

Can it be used as a gel? – Yes, topical forms reduce systemic side effects.

Is it an antibiotic? – No.

⚠️ Educational content only. Not a substitute for professional medical advice.