What is the safe dose of diclofenac (Nonsteroidal Anti-Inflammatory Drug (NSAID)) per kilogram in pediatric patients and at what age is it safe to administer?

Diclofenac Dosing and Safety in Pediatric Patients

Diclofenac can be safely used in children over 1 year of age at a dose of 0.5 mg/kg for rectal administration, 1 mg/kg for oral administration, and 0.3 mg/kg for intravenous administration. 1

Age-Based Safety Recommendations

Safe Age for Administration

• Children 1 year and older: Diclofenac can be safely administered 2, 1
• Children under 1 year: Not recommended due to limited safety and efficacy data
• Infants: Not adequately evaluated for safety

Route-Specific Dosing

1. Oral Administration:

   • Recommended dose: 1 mg/kg per dose 1
   • Maximum daily dose: Should not exceed adult dosing of 150 mg/day
   • Frequency: Usually divided into 2-3 doses per day

2. Rectal Administration:

   • Recommended dose: 0.5 mg/kg per dose 1
   • Higher bioavailability (63%) compared to oral suspension (36%) 1

3. Intravenous Administration:

   • Recommended dose: 0.3 mg/kg per dose 1
   • Should be used only when oral or rectal routes are not feasible

Pharmacokinetic Considerations

Children have different pharmacokinetic parameters compared to adults:

• Increased volume of distribution
• Increased clearance
• Similar elimination half-life 3

These differences may necessitate higher loading and/or maintenance doses in children compared to adults when calculated on a per-kilogram basis.

Safety Profile

Adverse Events

• Serious adverse reactions occur in fewer than 0.24% of children treated for acute pain 2
• The types of adverse reactions in children are similar to those seen in adults 2

Perioperative Use

• No significant increase in bleeding requiring surgical intervention when used perioperatively 2
• Exception: Some controversy exists regarding use in tonsillectomy due to potential increased risk of postoperative hemorrhage 3

Gastrointestinal Effects

• Children receiving diclofenac suffer less nausea and vomiting compared to non-NSAID alternatives (RR 0.6) 2

Clinical Applications

Pain Management

• Effective analgesic for perioperative acute pain in children 2
• Provides mild to moderate analgesia 3
• Opioid-sparing effect when used either alone or as an adjunct to regional anesthesia 3

Migraine Treatment

• In adolescents (12-17 years), diclofenac potassium for oral solution has shown favorable pharmacokinetic and safety profiles 4
• Rapidly absorbed with median time to maximum concentration of 15 minutes 4

Important Precautions

1. Asthmatic Children: More research is needed regarding safety in this population 2

2. Renal Function: Dose adjustment may be necessary in children with impaired renal function

3. Formulation Considerations:

   • When compounding is necessary, diclofenac powder is preferred over crushing enteric-coated tablets 5
   • Suspensions of diclofenac sodium (10 mg/mL) remain stable for up to 93 days 5

Monitoring Recommendations

• Monitor for gastrointestinal symptoms
• Assess for signs of bleeding, particularly with perioperative use
• Monitor renal function with prolonged use

Conclusion

Diclofenac is an effective analgesic for pediatric patients when used at appropriate doses. The pharmacokinetic meta-analysis provides evidence-based dosing recommendations of 0.3 mg/kg IV, 0.5 mg/kg rectal, and 1 mg/kg oral for children aged 1-12 years 1. These doses yield a similar area under the concentration-time curve to a 50 mg dose in adults, suggesting comparable efficacy with an acceptable safety profile.