Recommended Dosage and Usage of Diclofenac for Various Conditions
For the treatment of various conditions, diclofenac should be used at the lowest effective dose for the shortest duration possible, with specific dosages tailored to each condition. 1
Recommended Dosages by Condition
Osteoarthritis
- Standard dosage: 100-150 mg/day in divided doses 1
- 50 mg twice daily or three times daily 1
- In chronic CPP crystal inflammatory arthritis, oral NSAIDs including diclofenac (with gastroprotective treatment if indicated) are first-line options 2
Rheumatoid Arthritis
- Standard dosage: 150-200 mg/day in divided doses 1
- 50 mg three times daily or four times daily 1
- Higher doses may be needed for adequate inflammation control compared to osteoarthritis 3
Ankylosing Spondylitis
- Dosage: 100-150 mg/day in divided doses 3
- Continuous NSAID treatment is conditionally recommended over on-demand treatment for active ankylosing spondylitis 2
Pain Management
- Acute pain: 50 mg three times daily 1
- Primary dysmenorrhea: 50 mg three times daily 1
- Some patients may benefit from an initial dose of 100 mg followed by 50 mg doses 1
- For cancer pain, topical diclofenac options include:
Calcium Pyrophosphate Deposition (CPPD)/Pseudogout
- For acute attacks: 150 mg daily for 3 days, then 75 mg daily for 3 days 2
- For prophylaxis against recurrent attacks: low-dose oral diclofenac with gastroprotective treatment if indicated 2
Chronic Non-bacterial Osteitis (CNO)
- Starting at 150 mg/day in divided doses for active treatment phase 2
- Maintenance dose: 75-100 mg/day in divided doses 2
- Treatment response should be evaluated at 2-4 weeks after initiation 2
Administration Guidelines
- Take with meals to minimize gastrointestinal effects 3
- Different formulations (sodium enteric-coated tablets, sodium extended-release tablets, potassium immediate-release tablets) are not necessarily bioequivalent even at the same milligram strength 1
- Absorption is rapid and complete when given orally 4, 5
- Peak plasma concentrations occur 1.5-2 hours after ingestion in fasting subjects 3
Safety Considerations
Gastrointestinal Risk
- Risk of GI bleeding is dose-dependent:
- 75 mg/day: OR = 2.2 (95% CI 0.8-5.8)
- 75-150 mg/day: OR = 3.2 (95% CI 1.9-5.5)
150 mg/day: OR = 12.2 (95% CI 5.6-26.7) 2
- For patients with increased gastrointestinal risk, use with gastroprotective agents (PPIs, misoprostol, double doses of H2 blockers) or consider a COX-2 inhibitor instead 2
Special Populations
- Dosage adjustments are generally not required in elderly patients or those with renal or hepatic impairment 6
- Diclofenac has a relatively short elimination half-life (1.5 hours), which limits potential for drug accumulation 6, 5
Comparative Efficacy
- Diclofenac 150 mg/day has shown more favorable pain relief compared to ibuprofen 1200 mg/day and likely favorable outcomes compared to ibuprofen 2400 mg/day in osteoarthritis 7
- Diclofenac 100 mg/day has likely favorable outcomes compared to ibuprofen 1200 mg/day in alleviating pain 7
- In acute crystal-induced arthritis, parenteral glucocorticoids may provide quicker pain control than diclofenac in the first day, but similar efficacy by day 3 2
Common Pitfalls and Caveats
- Cardiovascular risk: Use caution in patients with cardiovascular disease 2
- Renal effects: Despite concerns about renal toxicity with long-term use, evidence to support this is sparse 2
- Drug interactions: Significant interactions have been reported with aspirin, lithium, digoxin, methotrexate, cyclosporin, cholestyramine, and colestipol 5
- Duration of therapy: Use for the shortest duration consistent with individual patient treatment goals 1
- Initial therapy: For degenerative arthritis, paracetamol (up to 4g daily) should be tried first before moving to NSAIDs like diclofenac 2