Can Relafen (nabumetone) be used to treat tendinitis?

Nabumetone (Relafen) for Tendinitis Treatment

Nabumetone (Relafen) is effective for treating tendinitis and can be used as a first-line nonsteroidal anti-inflammatory drug (NSAID) for pain and inflammation associated with tendon disorders. 1

Mechanism and Rationale

Nabumetone is a non-acidic NSAID prodrug that works through its active metabolite 6-methoxy-2-naphthylacetic acid (6-MNA), which preferentially inhibits COX-2 enzymes 2. This mechanism provides:

• Effective pain relief and anti-inflammatory effects
• Lower risk of gastrointestinal complications compared to traditional NSAIDs
• Once-daily dosing convenience (typically 1000-2000mg daily)

Treatment Approach for Tendinitis

First-Line Treatment

1. Nabumetone (Relafen): 1000mg once daily, typically at bedtime 2

   • For more severe cases: May increase to 1500-2000mg daily (split or single dose)
   • Duration: 1-2 weeks for acute tendinitis; reassess after this period

2. Concurrent Conservative Measures:

   • Relative rest of the affected tendon to prevent ongoing damage 1
   • Ice application for 10-minute periods through a wet towel 1
   • Eccentric strengthening exercises (particularly effective for Achilles and patellar tendinitis) 1

Monitoring and Follow-up

• Assess response after 1-2 weeks
• Monitor for gastrointestinal side effects (dyspepsia, abdominal pain, diarrhea)
• If inadequate response, consider:
  • Increasing dose (up to 2000mg daily)
  • Adding other modalities (physical therapy, corticosteroid injection)

Evidence for Efficacy

Nabumetone has demonstrated effectiveness for musculoskeletal inflammatory conditions including tendinitis 2, 3. A study specifically examining acute osteoarticular conditions found that nabumetone provided:

• Rapid improvement in pain and joint function
• Reduction in reactive edema
• Preventive analgesic effect that may increase pain threshold at capsular receptors and algoreceptors in tendons 3

Safety Considerations

Advantages of Nabumetone

• Lower incidence of gastrointestinal perforations, ulcerations, and bleeding compared to traditional NSAIDs 2
• Once-daily dosing improves compliance
• Minimal effect on renal function in short-term studies 2

Important Precautions

1. Tendon Rupture Risk: While treating tendinitis, be aware that bempedoic acid (not nabumetone) carries warnings about tendon rupture 1. This is not a documented risk with nabumetone but represents a general caution with inflammatory tendon conditions.

2. Common Side Effects:

   • Gastrointestinal: dyspepsia, diarrhea, abdominal pain, nausea 2
   • Other: headache 2

3. Contraindications:

   • History of NSAID-induced asthma or urticaria
   • Severe renal impairment
   • Third trimester of pregnancy

Special Populations

• Elderly: Consider starting at lower doses (500-1000mg daily)
• Patients with GI risk factors: Nabumetone may be preferred over traditional NSAIDs due to lower GI toxicity profile 2, 4
• Patients with cardiovascular risk: As with all NSAIDs, use caution and the lowest effective dose for the shortest duration

Alternative Approaches if Nabumetone Fails

If inadequate response to nabumetone after 2 weeks:

1. Corticosteroid Injections: Consider for localized tendinitis that doesn't respond to NSAIDs 1

   • Note: Potential toxicity including tendon rupture must be considered 1

2. Physical Therapy: Focused on eccentric strengthening and stretching exercises 1

3. Other Treatment Modalities:

   • Deep transverse friction massage 1
   • Extracorporeal shock wave therapy for chronic cases 1

In conclusion, nabumetone is an effective and relatively well-tolerated option for treating tendinitis, with advantages in gastrointestinal safety profile compared to traditional NSAIDs.