What is the appropriate rectal diclofenac dose for an adult and for a child over 12 years weighing at least 30 kg, and what are the contraindications?

Diclofenac Suppository Dosing

For adults and children over 12 years weighing at least 30 kg, the recommended rectal diclofenac dose is 100 mg administered immediately before or after procedures like ERCP, or 50 mg rectally for general pain management, with contraindications including active peptic ulcer disease, significant renal impairment, bleeding disorders, and hypersensitivity to NSAIDs.

Adult Dosing

Procedural Prophylaxis (Post-ERCP Pancreatitis)

• Administer 100 mg diclofenac rectally immediately before or after ERCP in all patients without contraindications 1
• This dosing applies universally to adults undergoing endoscopic procedures and has been shown to significantly reduce post-procedural pancreatitis 1

General Pain Management

• Standard rectal dosing for adults ranges from 50-100 mg per dose 2, 3
• Total daily dosage should not exceed 150 mg for most conditions 3
• The drug can be administered rectally when oral administration is not feasible 2

Pediatric Dosing (Children ≥12 Years, ≥30 kg)

Weight-Based Approach

• Rectal dose: 0.5-1 mg/kg every 8 hours 4
• For a child weighing 30 kg, this translates to 15-30 mg per dose 4
• Maximum daily dose should not exceed 3 mg/kg/day 4

Practical Considerations

• Children over 40 kg can receive adult dosing protocols 5
• Rectal administration provides bioavailability of approximately 35-63% compared to oral routes 6
• Ensure adequate hydration when administering diclofenac to pediatric patients 4

Absolute Contraindications

Gastrointestinal Contraindications

• Active peptic ulcer disease 4
• History of gastrointestinal bleeding or perforation related to NSAID use 1
• Patients should be monitored for rectal bleeding, particularly when combined with antibiotics 7

Renal Contraindications

• Significant renal impairment or creatinine clearance <50 mL/min 4
• End-stage renal disease may lead to metabolite accumulation 8

Hematologic Contraindications

• Active bleeding disorders or coagulopathy 4
• Thrombocytopenia requiring correction before administration 1
• Patients on anticoagulation require careful risk-benefit assessment 1

Cardiovascular Contraindications

• Hypersensitivity to NSAIDs, aspirin, or diclofenac 4
• Severe heart failure where fluid retention could be problematic 8

Important Clinical Caveats

Drug Interactions

• Avoid combining with other NSAIDs without expert consultation 1
• Significant interactions documented with aspirin, lithium, digoxin, methotrexate, and cyclosporin 8
• When used with antibiotics, monitor closely for gastrointestinal complications 7

Patient Consent Considerations

• Always discuss rectal administration with patients preoperatively 9
• 54% of surveyed patients preferred oral administration when available 9
• Some patients have strong preferences against rectal routes that should be respected 9

Absorption Characteristics

• Rectal diclofenac has variable bioavailability (35-63%) compared to oral formulations 6, 8
• Peak plasma concentrations occur later with rectal administration than oral routes 8
• Despite short plasma half-life (1.5 hours), the drug persists in synovial fluid providing prolonged anti-inflammatory effects 3, 8

Alternative Analgesic Options

• If diclofenac is contraindicated, consider acetaminophen/paracetamol as first-line alternative 7
• For pediatric patients, multimodal analgesia combining paracetamol with NSAIDs provides superior pain control 4, 5