Treatment of Renal Colic
Administer intramuscular diclofenac 75 mg immediately as first-line treatment, with the goal of achieving pain relief within 30 minutes of assessment. 1, 2
Immediate Assessment and Analgesia
- Patients with acute renal colic require medical assessment within 30 minutes of presentation. 1
- Pain relief must be provided within 30 minutes of assessment and maintained for at least 6 hours. 1, 2
- The intramuscular route is strongly preferred because oral and rectal routes are unreliable, and intravenous administration is impractical in primary care settings. 1, 2
First-Line Analgesic Choice
NSAIDs are superior to antispasmodics and equally effective as opioids, but with fewer side effects. 3, 4
- Intramuscular diclofenac 75 mg is the recommended first-line agent. 1, 2
- NSAIDs reduce pain scores significantly more than antispasmodics (mean difference -12.97 on VAS scale) and are 2.28 times more likely than placebo to achieve 50% pain reduction within the first hour. 4
- NSAIDs cause vomiting in only 6% of patients compared to 20% with opioids. 3
When NSAIDs Are Contraindicated
Use morphine sulfate combined with cyclizine (antiemetic) when NSAIDs cannot be used. 1, 2
NSAID contraindications include:
- Renal impairment or acute kidney injury 3
- Heart failure or renal artery stenosis 3
- Dehydration or concurrent nephrotoxic drug use 3
- Very elderly patients 3
- Pregnancy (NSAIDs should never be used) 3
- Previous peptic ulcer disease 5
Special considerations for opioid use:
- In patients with renal impairment, use fentanyl as it does not accumulate active metabolites. 2
- Avoid morphine, codeine, or tramadol as first-line agents in renal failure. 2
- Morphine is the preferred analgesic during pregnancy due to lower risk than NSAIDs. 3
Combination Therapy
Adding an NSAID to morphine provides additional benefit in approximately 10% of patients who fail monotherapy. 3
- However, adding antispasmodics to NSAIDs provides no additional benefit and is not recommended. 4
Criteria for Immediate Hospital Admission
Patients must be admitted immediately if any of the following are present: 1, 2, 6
- Shock or hemodynamic instability 1, 6
- Fever or signs of systemic infection (suggests infected obstructed kidney requiring urgent decompression) 1, 2, 6
- Failure to achieve pain control within 60 minutes of appropriate analgesia 1, 2, 6
- Abrupt recurrence of severe pain after initial relief 1, 6
- Age over 60 years with consideration of leaking abdominal aortic aneurysm 1, 7, 6
- Women with delayed menses (consider ectopic pregnancy) 1, 7, 6
- Anuria with obstruction (urologic emergency) 6
Follow-Up Protocol
- Telephone follow-up must occur one hour after initial assessment to verify pain control. 1, 2
- If pain persists at 60 minutes, arrange immediate hospital admission by telephone without requiring a second visit. 1
- Patients managed at home should maintain high fluid intake and strain urine to capture any passed stones. 1
- Arrange fast-track imaging within 7 days of symptom onset to confirm diagnosis and assess for complications. 1
Critical Pitfalls to Avoid
- Never delay analgesia while waiting for diagnostic tests or imaging. 2, 7
- Do not discharge patients before ensuring adequate pain control for at least 6 hours. 2, 7
- Absence of hematuria does not exclude renal colic (present in only 80% of cases). 1, 7
- Missing signs of infected obstructed kidney can lead to rapid progression to sepsis—this requires urgent decompression via percutaneous nephrostomy or ureteral stenting. 2, 7, 6
Adjunctive Medical Expulsion Therapy
For small distal ureteral stones managed expectantly, tamsulosin increases spontaneous stone passage rates by approximately 50%. 8, 5