Comprehensive Guide to Diclofenac: Uses, Dosage, Side Effects, and More
What is Diclofenac?
Overview of Diclofenac
Generic Name: Diclofenac
Brand Name: Voltaren, Cataflam, Flector, generics
Drug Group: Non-steroidal anti-inflammatory drug (NSAID)
Commonly Used For
- Relieve arthritis pain.
- Manage acute injuries.
- Reduce postoperative pain.
Key Characteristics
Form: Oral tablets (25 mg, 50 mg, 75 mg), extended-release tablets (100 mg), topical gel (1%), patches (1.3%), and injectable (75 mg/3 mL) (detailed in Dosage section).
Mechanism: Inhibits prostaglandin synthesis via COX inhibition.
Approval: FDA-approved (1988 for Voltaren) and EMA-approved for pain and inflammation.
Indications and Uses of Diclofenac
Diclofenac is indicated for a wide range of inflammatory and pain-related conditions, leveraging its anti-inflammatory and analgesic properties:
Osteoarthritis: Alleviates joint pain and stiffness in osteoarthritis, improving mobility in hips, knees, and hands, effective as both oral and topical therapy.
Rheumatoid Arthritis: Reduces synovial inflammation and pain in rheumatoid arthritis, supporting long-term disease management, often combined with disease-modifying agents.
Ankylosing Spondylitis: Relieves spinal pain and stiffness in ankylosing spondylitis, enhancing posture and function, with regular monitoring.
Acute Pain: Manages postoperative pain (e.g., dental, orthopedic), menstrual cramps, and migraine headaches, providing rapid relief within 30–60 minutes.
Musculoskeletal Injuries: Treats sprains, strains, and tendonitis by reducing local inflammation, with topical forms ideal for localized application.
Gout Attacks: Controls acute gouty arthritis flare-ups by lowering uric acid-induced inflammation, used as a short-term option.
Off-Label Uses: Includes management of temporomandibular joint (TMJ) disorders to reduce jaw pain, treatment of chronic back pain with neuropathic components, and adjunctive therapy in fibromyalgia to alleviate muscle soreness, supported by clinical studies and pain management guidelines.
Post-Surgical Inflammation: Reduces swelling and pain after cataract surgery (topical) or orthopedic procedures, enhancing recovery, based on ophthalmologic and surgical data.
Dysmenorrhea: Eases primary dysmenorrhea by inhibiting uterine prostaglandin release, offering an alternative to hormonal treatments.
Bursitis and Tendinitis: Addresses inflammation in bursitis (e.g., shoulder) and tendinitis (e.g., Achilles), with topical or oral forms tailored to severity.
Dosage of Diclofenac
Dosage for Adults
Oral (Immediate-Release, e.g., Cataflam):
- Acute Pain: 50 mg every 8 hours or 25 mg every 6 hours, maximum 150 mg/day.
- Osteoarthritis/Rheumatoid Arthritis: 50 mg two to three times daily or 75 mg twice daily, maximum 150 mg/day.
Oral (Extended-Release, e.g., Voltaren XR):
- 100 mg once daily or 100 mg in the morning and evening, maximum 200 mg/day for severe cases.
Topical (Gel, e.g., Voltaren):
- 2–4 g applied to affected area 4 times daily, maximum 32 g/day per joint area.
Transdermal Patch (e.g., Flector):
- 1 patch (10 cm², 1.3% diclofenac) applied to painful area every 12 hours, maximum 2 patches/day.
Injectable:
- 75 mg via intramuscular injection once or divided into two 37.5 mg doses, maximum 150 mg/day for 2 days.
Dosage for Children
Oral (≥14 years for Juvenile Idiopathic Arthritis):
- 1–3 mg/kg/day in divided doses (e.g., 25–50 mg twice daily), maximum 150 mg/day, under pediatric rheumatologist supervision.
- Not recommended under 14 years.
Topical: Not approved for children; use only in adolescents (12–17) with severe localized pain, starting at 1 g twice daily, under specialist care.
Dosage for Pregnant Women
Pregnancy Category C/D: Avoid in third trimester due to closure of ductus arteriosus risk; use only in first/second trimesters if benefits outweigh risks. Consult an obstetrician, with fetal monitoring.
Dosage Adjustments
Renal Impairment:
- CrCl 30–60 mL/min: Reduce oral dose to 50 mg/day; CrCl <30 mL/min: Avoid unless benefit outweighs risk.
Hepatic Impairment:
- Mild: No adjustment; moderate to severe: Reduce to 50 mg/day and monitor closely.
Elderly: Start with 25–50 mg oral or 1 g topical once daily; increase cautiously to 100–150 mg/day due to slower metabolism.
Cardiovascular Risk: Limit to lowest effective dose (e.g., 50 mg/day) in patients with heart disease history.
Additional Considerations
- Take this active ingredient with food or milk to minimize gastrointestinal irritation.
- Apply topical forms to clean, dry skin, avoiding open wounds or eyes; wash hands after use.
How to Use Diclofenac
Administration:
Oral: Swallow tablets whole with a full glass of water or milk, with or after food; avoid lying down for 10–15 minutes post-dose.
Topical Gel: Apply a thin layer to the affected area, gently rubbing until absorbed, using the dosing card for accuracy; avoid bandaging tightly.
Transdermal Patch: Place on intact skin, press firmly for 30 seconds, and remove after 12 hours; alternate application sites.
Injectable: Administered by a healthcare provider via deep intramuscular injection, preferably in the gluteal region.
Timing: Use every 6–8 hours for immediate-release, once daily for extended-release, or as prescribed for topical/patch forms, maintaining consistency.
Monitoring: Watch for stomach pain, swelling, or skin irritation; check for signs of bleeding (e.g., black stools).
Additional Tips:
- Store at 15–30°C (59–86°F), protecting from moisture and heat.
- Clean application site before reapplying topical forms; avoid sun exposure on treated areas.
- Report severe headache, chest pain, or signs of allergic reaction (e.g., rash) immediately.
Contraindications for Diclofenac
Hypersensitivity: Patients with a known allergy to Diclofenac, other NSAIDs (e.g., ibuprofen), or aspirin.
Severe Renal Impairment: Avoid if CrCl <30 mL/min due to risk of acute kidney injury.
Severe Hepatic Impairment: Contraindicated in Child-Pugh Class C due to hepatotoxicity risk.
Active Gastrointestinal Bleeding: Contraindicated due to increased ulcer or perforation risk.
Third Trimester Pregnancy: Avoid due to fetal cardiovascular and renal effects.
History of Asthma with NSAID Sensitivity: Contraindicated due to potential bronchospasm.
Coronary Artery Bypass Graft (CABG) Surgery: Contraindicated perioperatively due to cardiovascular event risk.
Warnings & Precautions for Diclofenac
General Warnings
Cardiovascular Risk: Increases risk of heart attack or stroke, especially with long-term use; use lowest dose for shortest duration.
Gastrointestinal Risk: May cause ulcers, bleeding, or perforation; monitor for abdominal pain or melena.
Renal Toxicity: Risk of kidney injury or fluid retention; avoid in dehydration or heart failure.
Hepatic Effects: Elevated liver enzymes possible; check monthly for the first 4–6 months.
Hypertension: May worsen blood pressure control; monitor regularly.
Additional Warnings
Anaphylactic Reactions: Rare but severe; discontinue if rash, swelling, or wheezing occurs.
Skin Reactions: Risk of Stevens-Johnson syndrome or toxic epidermal necrolysis; stop at first sign of rash.
Asthma Exacerbation: Potential bronchospasm in aspirin-sensitive patients; use cautiously.
Bone Marrow Suppression: Rare thrombocytopenia or agranulocytosis; perform periodic blood counts.
Delayed Healing: May impair soft tissue or bone healing post-surgery; limit use in recovery phase.
Use in Specific Populations
Pregnancy: Category C/D; avoid in third trimester; use alternatives if possible.
Breastfeeding: Excreted in minimal amounts; monitor infant if used.
Elderly: Higher risk of GI and cardiovascular events; start with lower doses.
Children: Limited use; supervise closely in approved indications.
Renal/Hepatic Impairment: Adjust dose; avoid in severe cases.
Additional Precautions
- Inform your doctor about heart disease, liver issues, or recent surgery before starting this medication.
- Avoid abrupt cessation; taper if discontinuing long-term therapy.
Overdose and Management of Diclofenac
Overdose Symptoms
- Nausea, vomiting, or abdominal pain.
- Severe cases: Gastrointestinal bleeding, renal failure, or seizures.
- Drowsiness, headache, or tinnitus as early signs.
- Hypotension or respiratory depression with extremely high doses.
Immediate Actions
Contact the Medical Team: Seek immediate medical help.
Supportive Care: Administer activated charcoal within 1–2 hours, monitor vital signs, and provide IV fluids.
Specific Treatment: Use proton pump inhibitors for GI bleeding, dialysis for renal failure, or benzodiazepines for seizures; manage symptoms (e.g., antacids for irritation).
Monitor: Check liver function, renal output, and coagulation parameters for 24–48 hours.
Additional Notes
- Overdose risk increases with polypharmacy; store securely.
- Report persistent symptoms (e.g., confusion, severe vomiting) promptly.
Side Effects of Diclofenac
Common Side Effects
- Stomach Pain (10–20%, reduced with food)
- Nausea (5–15%, manageable with antacids)
- Headache (5–10%, relieved with hydration)
- Dizziness (3–8%, common with initial use)
- Rash (2–6%, transient with topical forms)
- Edema (2–5%, monitorable with weight check)
These effects may decrease with dose adjustment or tolerance.
Serious Side Effects
Seek immediate medical attention for:
- Gastrointestinal: Ulcers, bleeding, or perforation (e.g., black stools, vomiting blood).
- Cardiovascular: Chest pain, myocardial infarction, or stroke.
- Renal: Oliguria, acute kidney injury, or hypertension.
- Hepatic: Jaundice, hepatitis, or liver failure.
- Allergic: Anaphylaxis, angioedema, or severe rash (e.g., Stevens-Johnson syndrome).
- Hematologic: Anemia, thrombocytopenia, or agranulocytosis.
Additional Notes
- Regular monitoring for GI, liver, and kidney function is advised.
- Report any unusual symptoms (e.g., vision changes, severe fatigue) immediately to a healthcare provider.
Drug Interactions with Diclofenac
This active ingredient may interact with:
- Warfarin: Increases bleeding risk; monitor INR.
- ACE Inhibitors: Reduces antihypertensive effect; adjust dose.
- Lithium: Elevates lithium levels; monitor closely.
- Methotrexate: Increases toxicity; avoid concurrent high doses.
- Alcohol: Potentiates GI irritation; avoid consumption.
Action: Provide your healthcare provider with a complete list of medications.
Patient Education or Lifestyle
Medication Adherence: Take this NSAID as prescribed to manage pain or inflammation, following the exact schedule.
Monitoring: Report stomach pain, swelling, or yellowing of skin immediately.
Lifestyle: Avoid smoking or excessive alcohol; use sun protection with topical forms.
Diet: Take with food or milk to reduce GI upset; avoid high-fat meals with oral forms.
Emergency Awareness: Know signs of bleeding or heart attack; seek care if present.
Follow-Up: Schedule regular check-ups every 3–6 months to monitor kidney and liver function.
Pharmacokinetics of Diclofenac
Absorption: Well-absorbed orally (peak at 2–3 hours); topical absorption varies (4–6 hours).
Distribution: Volume of distribution ~1.3 L/kg; 99% protein-bound.
Metabolism: Hepatic via CYP2C9 to inactive metabolites.
Excretion: Primarily renal (65%) and biliary (35%); half-life 1–2 hours.
Half-Life: 1–2 hours, with active metabolites extending effect.
Pharmacodynamics of Diclofenac
This drug exerts its effects by:
Inhibiting COX-1 and COX-2, reducing prostaglandin synthesis.
Alleviating pain and inflammation in joints and muscles.
Lowering fever by acting on the hypothalamic thermostat.
Demonstrating dose-dependent GI and cardiovascular risks, requiring cautious use.
Storage of Diclofenac
- Temperature: Store at 15–30°C (59–86°F); protect from moisture.
- Protection: Keep in original container, away from heat.
- Safety: Store out of reach of children.
- Disposal: Dispose of unused product per local regulations or consult a pharmacist.
Frequently Asked Questions (FAQs)
Q: What does Diclofenac treat?
A: This medication treats arthritis and acute pain.
Q: Can this active ingredient cause stomach issues?
A: Yes, stomach pain may occur; take with food.
Q: Is Diclofenac safe for children?
A: Yes, for 14+ years with a doctor’s guidance.
Q: How is this drug taken?
A: Orally, topically, or by injection, as directed.
Q: How long is Diclofenac treatment?
A: Short-term for pain; variable for arthritis.
Q: Can I use Diclofenac if pregnant?
A: No, avoid in third trimester; consult a doctor.
Regulatory Information for Diclofenac
This medication is approved by:
U.S. Food and Drug Administration (FDA): Approved in 1988 (Voltaren) for pain and inflammation.
European Medicines Agency (EMA): Approved for arthritis and acute pain.
Other Agencies: Approved globally for inflammatory conditions; consult local guidelines.
References
- U.S. Food and Drug Administration (FDA). (2023). Voltaren (Diclofenac) Prescribing Information.
- Official FDA documentation detailing the drug’s approved uses, dosage, and safety.
- European Medicines Agency (EMA). (2023). Diclofenac Summary of Product Characteristics.
- EMA’s comprehensive information on the medication’s indications and precautions in Europe.
- National Institutes of Health (NIH). (2023). Diclofenac: MedlinePlus Drug Information.
- NIH resource providing detailed information on the drug’s uses, side effects, and precautions.
- World Health Organization (WHO). (2023). WHO Model List of Essential Medicines: Diclofenac.
- WHO’s inclusion of Diclofenac for pain relief.
- Journal of Rheumatology. (2022). Diclofenac in Arthritis Management.
- Peer-reviewed article on Diclofenac efficacy (note: access may require a subscription).
