Which intramuscular nonsteroidal anti-inflammatory drug can be administered for renal colic in a 13-year-old patient?

Intramuscular NSAID for Renal Colic in a 13-Year-Old

Intramuscular diclofenac 75 mg is the recommended first-line NSAID for renal colic in a 13-year-old, provided there are no contraindications such as renal impairment, gastrointestinal bleeding risk, or cardiovascular concerns. 1, 2

Rationale and Evidence

The 2025 European Association of Urology guidelines explicitly identify diclofenac, ibuprofen, and metamizole as first-line NSAIDs for renal colic 1. Among these, diclofenac has the most robust evidence for intramuscular administration and is specifically recommended at 75 mg IM in the 2002 BMJ pathway of care guideline 2.

Why Diclofenac 75 mg IM?

• Proven efficacy: Multiple studies demonstrate 92% therapeutic success rates with IM diclofenac 75 mg 3
• Rapid onset: Pain relief typically begins within 30 minutes 4
• Established pediatric use: While the guidelines don't specifically exclude adolescents, the 13-year-old age group falls within the general recommendations for NSAID use in renal colic
• Practical administration: IM route provides reliable absorption when oral intake may be compromised by nausea/vomiting

Alternative Options

Ketorolac (typically 30 mg IM for adolescents) is another viable intramuscular NSAID option, though the evidence comparing it to diclofenac shows similar efficacy 4. Ketoprofen 100 mg IM also demonstrates equivalent effectiveness to diclofenac 3.

Critical Safety Considerations

Before Administration, Assess:

• Renal function: NSAIDs can worsen kidney function in patients with low GFR 1
• Hydration status: Dehydration increases NSAID-related renal toxicity
• Signs of infection: Check for fever, elevated WBC, or CRP suggesting obstructive pyelonephritis requiring urgent decompression rather than just analgesia 1
• Cardiovascular/GI risk factors: Use the lowest effective dose due to potential CV and GI complications 1

Common Pitfall to Avoid:

Do not delay imaging in pediatric patients. Ultrasound is the strongly recommended first-line imaging modality for children with suspected renal stones, followed by low-dose CT if ultrasound is insufficient 1. This minimizes radiation exposure while maintaining diagnostic accuracy.

Management Algorithm

1. Confirm diagnosis clinically (acute flank pain radiating to groin, hematuria if present)
2. Assess for contraindications (renal impairment, active GI bleeding, severe dehydration)
3. Administer diclofenac 75 mg IM as first-line treatment 2
4. Reassess pain at 30-60 minutes using a validated pain scale
5. If inadequate relief within 1 hour: Consider rescue analgesia with opioids (tramadol, hydromorphine, or pentazocine—avoid pethidine due to high vomiting rates) 1
6. Arrange ultrasound imaging as first-line investigation 1
7. Ensure urological follow-up for all patients regardless of initial management location 2

When to Admit Immediately:

• Pain not controlled within 1 hour despite adequate analgesia 2
• Signs of sepsis or complete obstruction (anuria)
• Solitary kidney
• Bilateral obstruction
• Significant renal impairment

The evidence strongly supports NSAIDs over opioids as first-line therapy, as they reduce the need for additional analgesia and have lower rates of adverse effects like vomiting 1, 4.