What is the recommended dosage and precautions for prescribing Diclofenac (nonsteroidal anti-inflammatory drug (NSAID)) to a patient with arthritis, particularly in older adults or those with impaired renal function, history of gastrointestinal bleeding, or taking other medications?

Diclofenac for Arthritis: Dosing and Precautions

Diclofenac should be used at the minimum effective dose for the shortest duration possible after evaluating gastrointestinal, renal, and cardiovascular risks, with typical dosing of 100-150 mg/day for osteoarthritis and 150-200 mg/day for rheumatoid arthritis, divided into 2-3 doses. 1, 2

Standard Dosing Recommendations

Osteoarthritis

• 100-150 mg/day in divided doses: 50 mg twice daily or three times daily 2
• Consider topical diclofenac gel as first-line before oral formulations for knee osteoarthritis due to markedly reduced systemic exposure and avoidance of gastrointestinal, cardiovascular, liver, and renal toxicity 3

Rheumatoid Arthritis

• 150-200 mg/day in divided doses: 50 mg three times daily or four times daily 2
• Different formulations (enteric-coated, extended-release, immediate-release) are not bioequivalent even at the same milligram strength 2

Critical Risk Assessment Before Prescribing

Gastrointestinal Risk Factors

NSAIDs cause dose-dependent gastrointestinal bleeding risk (e.g., diclofenac 75 mg: OR=2.2; 75-150 mg: OR=3.2; >150 mg: OR=12.2). 1

For patients with increased GI risk, use one of these strategies:

• Non-selective NSAID plus proton pump inhibitor 1
• Non-selective NSAID plus misoprostol 1
• Non-selective NSAID plus double-dose H2-receptor antagonist 1
• COX-2 selective inhibitor (though cardiovascular considerations apply) 1

Renal Function Considerations

• Use with extreme caution in patients with low creatinine clearance 1
• NSAIDs were implicated in 23.5% of adverse drug reaction hospitalizations in older adults 1
• Diclofenac may further decrease renal function even in mild-to-moderate impairment 4

Cardiovascular Risk

• Assess for uncontrolled hypertension, heart failure, and cardiovascular disease before prescribing 1
• Particular caution required in intravascularly depleted states such as congestive heart failure 1

Special Population: Older Adults

In elderly patients (≥75 years), topical NSAIDs are strongly preferred over oral NSAIDs when applicable. 4

Key considerations for older adults:

• Start with the lowest dose due to higher risk for adverse NSAID effects 1
• NSAID-associated adverse events increase in frequency and severity with age 1
• Gastrointestinal toxicity may be dose-related and time-dependent 1
• Consider frailty and history of sensitivity to medications 1

Treatment Algorithm

Step 1: Risk Stratification

Evaluate for:

• History of gastrointestinal bleeding or peptic ulcer disease 1
• Renal impairment (check creatinine clearance) 1
• Cardiovascular disease or risk factors 1
• Concomitant use of antiplatelet agents (especially low-dose aspirin) 1
• Age ≥75 years 4

Step 2: Route Selection

• If knee or hand osteoarthritis: Start with topical diclofenac gel 3
• If other joints or inflammatory arthritis: Proceed to oral formulation 1

Step 3: Gastroprotection Decision

If ANY of the following are present, add gastroprotection:

• Age >65 years 1
• History of GI bleeding or ulcer 1
• Concomitant aspirin use 1
• Concomitant corticosteroid use 1

Step 4: Dosing Initiation

• Osteoarthritis: Start 50 mg twice daily 2
• Rheumatoid arthritis: Start 50 mg three times daily 2
• Adjust to lowest effective dose after observing initial response 2

Duration of Therapy

NSAIDs should be used as temporary symptomatic therapy, not indefinitely. 1

• Use for shortest time possible to minimize cumulative adverse effects 1
• Topical NSAIDs have safety data for short-term use (<4 weeks in many studies) with limited long-term data 1
• Regular monitoring required if extended use is necessary 1

Common Pitfalls to Avoid

• Do not combine diclofenac with other NSAIDs (including over-the-counter products) as this increases adverse event risk without additional benefit 3
• Do not use standard-dose H2-blockers for gastroprotection as they are less effective than proton pump inhibitors, double-dose H2-blockers, or misoprostol 1
• Do not assume all diclofenac formulations are interchangeable at the same dose 2
• Do not prescribe without assessing cardiovascular and renal status in older adults 1
• Do not use oral NSAIDs as first-line in elderly patients when topical formulations are appropriate 4, 3

Monitoring Requirements

When using diclofenac beyond short-term:

• Monitor renal function periodically, especially in older adults or those with baseline impairment 1
• Assess for gastrointestinal symptoms at each visit 1
• Re-evaluate cardiovascular status if risk factors present 1
• Reassess need for continued therapy regularly 1