Diclofenac Sodium - Uses, Dosage, Side Effects, Warnings & Interactions
A Complete Evidence-Based Guide | Medicines Explorer
1. How Does Diclofenac Sodium Work? (Mechanism of Action)
Diclofenac Sodium belongs to the phenylacetic acid class of NSAIDs. When you have an injury or arthritis, your body produces chemicals called prostaglandins at the site of damage. These prostaglandins cause pain, swelling, redness, and fever. Diclofenac blocks both COX-1 and COX-2 enzymes, but has a slightly more affinity for COX-2. By blocking these enzymes, it stops prostaglandin synthesis, thereby providing analgesic, anti-inflammatory, and antipyretic effects. Unlike opioids, it does not cause sedation or addiction.
It is rapidly and completely absorbed after oral administration, with peak plasma levels reached within 2-3 hours. It has extensive first-pass metabolism and is mainly excreted by the kidneys.
2. Therapeutic Uses of Diclofenac Sodium
Diclofenac Sodium is one of the most prescribed painkillers worldwide. Its uses are broad:
- Musculoskeletal Pain: Rheumatoid Arthritis, Osteoarthritis, Ankylosing Spondylitis, Gout attack.
- Acute Pain Conditions: Post-operative pain, Dental pain, Dysmenorrhea (period pain), Migraine headache.
- Soft Tissue Injuries: Sprains, Strains, Tendonitis, Bursitis, Frozen shoulder.
- Renal Colic & Biliary Colic: Very effective for severe colicky pain due to kidney stones.
- Topical Use (Gel): Knee and hand osteoarthritis, sports injuries, muscle pain.
- Ophthalmic Use: Post-cataract surgery inflammation and pain.
3. Dosage and Administration - Detailed Table
Dosage depends on age, condition, and formulation. Always follow your doctor's prescription. Never exceed 150 mg per day orally without supervision.
Important Tip: Take oral diclofenac with a full glass of water and after meals to reduce stomach upset. Do not lie down for 15-20 minutes after taking the tablet.
4. Side Effects of Diclofenac Sodium
| Common Side Effects | Serious - Seek Immediate Medical Help |
|---|---|
| Stomach pain, Nausea, Indigestion | Black tarry stools, Vomiting blood (GI Bleed) |
| Diarrhea or Constipation, Gas | Chest pain, Shortness of breath (Heart attack/stroke risk) |
| Headache, Dizziness, Drowsiness | Severe allergic reaction - swelling of face, rash |
| Mild increase in BP | Kidney failure - less urination, swelling in legs |
| Skin rash with gel application | Liver damage - yellow skin, dark urine |
5. Warnings and Precautions
- Cardiovascular Risk: All NSAIDs, including diclofenac, may increase risk of heart attack and stroke, especially with long-term high dose use.
- Gastrointestinal Risk: Can cause stomach ulcers and bleeding. Avoid if you have active peptic ulcer. Combine with a PPI like omeprazole if doctor advises for long-term use.
- Kidney & Liver: Not recommended in severe renal or hepatic impairment. Monitor kidney function with prolonged use.
- Asthma: Patients with aspirin-induced asthma should avoid diclofenac.
- Pregnancy: Avoid in third trimester - can cause premature closure of ductus arteriosus in fetus. First and second trimester only if clearly needed and prescribed.
- Elderly: Use lowest effective dose for shortest duration. Elderly are more prone to side effects.
6. Drug Interactions
- Anticoagulants (Warfarin, Heparin): Increases bleeding risk.
- Antihypertensives (ACE inhibitors, Diuretics): Diclofenac reduces their blood pressure lowering effect and increases kidney risk.
- SSRIs: Increased risk of GI bleeding.
- Methotrexate & Lithium: Diclofenac increases their blood levels and toxicity.
- Alcohol: Increases stomach irritation and bleeding risk - avoid alcohol.
7. Diclofenac Sodium vs Diclofenac Potassium - Key Difference
| Feature | Diclofenac Sodium | Diclofenac Potassium |
|---|---|---|
| Onset | Slower (20-30 min) | Faster (10-20 min) - Better for acute pain |
| Best For | Chronic conditions like arthritis | Acute pain - migraine, dental, period pain |
| Duration | Longer acting | Shorter but quick relief |
8. Overdose and Missed Dose
Missed Dose: Take as soon as you remember. If it's near next dose, skip it. Never double dose.
Overdose Symptoms: Severe abdominal pain, vomiting, drowsiness, kidney failure, low blood pressure. There is no specific antidote. Treatment is symptomatic and supportive. Seek emergency help immediately.
9. Storage and Patient Counseling Tips
Store below 30°C in a dry place, away from direct sunlight. Keep out of reach of children. For gel: For external use only, do not apply on broken skin or wounds, wash hands after application. Do not use gel with oral diclofenac together unless doctor says. For long-term users, regular check-up for blood pressure, kidney function, and complete blood count is advised.
10. Frequently Asked Questions (FAQs)
Q1: Is Diclofenac Sodium a painkiller or antibiotic?
It is a painkiller (NSAID), not an antibiotic. It does not treat infections, only pain, swelling, and fever associated with inflammation.Q2: Can I take Diclofenac Sodium daily?
Only if prescribed by your doctor for chronic conditions like arthritis. For acute pain, use it for shortest duration possible, usually 2-3 days. Long-term daily use increases heart, kidney, and stomach risks.Q3: Is Diclofenac Sodium safe for kidney patients?
No, NSAIDs can worsen kidney function. Patients with chronic kidney disease should avoid it or use only under strict nephrologist supervision with dose adjustment.Q4: Can I apply Diclofenac gel during pregnancy?
Generally topical gel has very low systemic absorption and is considered safer than oral tablets, but still consult your gynecologist before use, especially in third trimester.Q5: Which is stronger - Ibuprofen or Diclofenac Sodium?
Diclofenac is considered more potent than ibuprofen on a mg-to-mg basis for inflammatory pain. 50mg diclofenac is roughly equivalent to 400mg ibuprofen, but diclofenac also has higher cardiovascular risk with long-term use.Looking for Trusted Medicine Information?
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