What is the recommended dosage and usage of diclofenac (Non-Steroidal Anti-Inflammatory Drug) for pain and inflammatory conditions?

Diclofenac Dosage and Usage Recommendations

The recommended dosage of diclofenac for pain and inflammatory conditions is 50-150 mg/day in divided doses, using the lowest effective dose for the shortest duration possible to minimize adverse effects. 1, 2

Specific Dosing by Condition

Osteoarthritis

• Recommended dose: 100-150 mg/day in divided doses
  • 50 mg twice or three times daily 1
• Topical formulations preferred for localized pain in superficial joints
  • Diclofenac gel: Apply 3 times daily
  • Diclofenac patch (180 mg): Apply once or twice daily 2

Rheumatoid Arthritis

• Recommended dose: 150-200 mg/day in divided doses
  • 50 mg three or four times daily 1

Acute Pain/Primary Dysmenorrhea

• Recommended dose: 50 mg three times daily
• Some patients may benefit from an initial 100 mg dose, followed by 50 mg doses 1

Chronic CPP Crystal Inflammatory Arthritis

• Oral NSAIDs (including diclofenac) are first-line options
• Use with gastroprotective treatment if indicated 3

Administration Guidelines

• Take with meals to minimize gastrointestinal effects
• Different formulations (sodium enteric-coated, extended-release, potassium immediate-release) are not bioequivalent even at the same milligram strength 1
• For over-the-counter use: Initial dose of two 12.5 mg tablets (25 mg), followed by one or two tablets every 4-6 hours, not exceeding 75 mg/day 4

Safety Considerations

Cardiovascular Risk

• Diclofenac may increase risk of serious cardiovascular thrombotic events, myocardial infarction, and stroke 3
• Risk increases with:
  • Duration of use
  • Pre-existing cardiovascular disease
  • Higher doses (particularly >150 mg/day) 3
• Meta-analysis shows diclofenac has a higher cardiovascular risk (RR=1.63,95% CI 1.12-2.37) compared to other NSAIDs 3

Gastrointestinal Risk

• Causes increased risk of serious GI adverse events including bleeding, ulceration, and perforation 3, 1
• Risk reduction strategies:
  • Use lowest effective dose for shortest duration
  • Co-administer with gastroprotective agents (PPIs, misoprostol, double-dose H2 blockers) in high-risk patients 3
  • Consider selective COX-2 inhibitors in patients with increased GI risk 3

Special Populations

• Elderly patients: No specific dosage adjustment required, but use caution due to increased risk of adverse effects 2
• Patients with renal or hepatic impairment: No specific dosage adjustments required, but monitor closely 5

Monitoring Recommendations

• Evaluate treatment response after 2-4 weeks
• Monitor for:
  • Gastrointestinal symptoms
  • Signs of renal impairment
  • Cardiovascular adverse effects
• If more than four breakthrough doses needed in 24 hours, consider dose adjustment 2

Clinical Pearls

• Diclofenac has a relatively short elimination half-life (1.5 hours) but persists in synovial fluid, allowing for effective pain control 6
• For acute pain management, diclofenac provides rapid onset of action (peak plasma concentration in 30 minutes with immediate-release formulation) 4
• Combination therapy with acetaminophen can improve efficacy while minimizing NSAID dose 2
• NSAIDs may delay natural healing processes since inflammation is a necessary component of tissue recovery 2

Diclofenac is an effective analgesic and anti-inflammatory medication with efficacy comparable to other NSAIDs, but careful consideration of cardiovascular and gastrointestinal risks is essential when prescribing.