What is the proper administration and dosing of diclofenac sodium (Nonsteroidal Anti-Inflammatory Drug (NSAID)) injections via intramuscular (IM) or intravenous (IV) routes?

Proper Administration and Dosing of Diclofenac Sodium Injections (IM and IV)

For acute pain management, diclofenac sodium can be administered via intramuscular injection at a dose of 75 mg or intravenously as a small volume bolus at doses of 37.5-75 mg, with both routes showing similar efficacy but IV administration providing faster onset of action. 1, 2, 3

Routes of Administration

Intravenous (IV) Administration

• Dosage: 37.5-75 mg per dose
• Administration: Can be given as a small volume bolus injection
• Frequency: Every 6 hours as needed
• Advantages:
  • Rapid onset of action
  • 100% bioavailability
  • Particularly valuable when immediate analgesia is required 1
  • Avoids first-pass metabolism (oral diclofenac has only about 50% bioavailability) 2

Intramuscular (IM) Administration

• Dosage: 75 mg per dose
• Administration: Deep IM injection
• Frequency: Every 6-8 hours as needed
• Advantages:
  • Option when IV access is unavailable
  • Established efficacy for acute pain management 3

Clinical Applications

Acute Pain Management

• Postoperative Pain: Both IV and IM diclofenac are effective for managing moderate to severe postoperative pain 4
• Renal Colic: IV diclofenac is recommended as first-line treatment for acute renal colic 1
• Crystal-Induced Arthritis: Effective for acute attacks of crystal-induced arthritis 5

Safety Considerations

Contraindications

• History of hypersensitivity to diclofenac or other NSAIDs
• Active gastrointestinal bleeding or ulceration
• Severe renal impairment
• Severe hepatic impairment
• Third trimester of pregnancy
• History of asthma, urticaria, or allergic reactions after taking aspirin or other NSAIDs

Precautions

• Cardiovascular Risk: Use lowest effective dose for shortest duration possible, especially in patients with cardiovascular risk factors 1
• Gastrointestinal Risk: Consider gastroprotective agents in high-risk patients
• Renal Function: Monitor renal function in at-risk patients, though dosing adjustment is not generally required in mild to moderate renal dysfunction 3
• Hepatic Function: Metabolism is primarily hepatic, so patients with hepatic disease may require reduced doses 3

Practical Administration Tips

IV Administration

• Administer as a slow IV bolus over at least 15 seconds
• Newer formulations containing hydroxypropyl-β-cyclodextrin (HPβCD) allow for easier IV bolus administration compared to older formulations that required 30-120 minute infusions 4, 6
• Monitor injection site for phlebitis

IM Administration

• Inject deeply into the gluteal muscle
• Use proper aseptic technique
• Rotate injection sites if multiple doses are required
• Local tolerability is generally rated as good to excellent 7

Common Pitfalls to Avoid

1. Rapid IV Administration: Administering IV diclofenac too rapidly can increase the risk of adverse reactions
2. Superficial IM Injections: Ensure deep IM injection to avoid local tissue irritation
3. Prolonged Use: Extended use increases risk of cardiovascular and gastrointestinal adverse events
4. Inadequate Monitoring: Failure to monitor for signs of adverse effects, especially in high-risk patients
5. Concomitant NSAID Use: Avoid administering with other NSAIDs as this increases risk of adverse effects without providing additional benefit

By following these guidelines, healthcare providers can effectively and safely administer diclofenac sodium injections for pain management in appropriate clinical scenarios.