What is the best analgesic for ureteric colic?

Best Analgesic for Ureteric Colic

Intramuscular diclofenac 75 mg is the gold-standard first-line analgesic for acute ureteric colic, providing superior pain relief within 30 minutes compared to opioids, with fewer side effects and reduced need for rescue medication. 1, 2, 3

First-Line Treatment: NSAIDs (Specifically Diclofenac)

• Diclofenac 75 mg intramuscularly is the preferred agent and route because it provides clinically meaningful pain reduction within 30 minutes and maintains analgesia for at least 6 hours. 1, 2, 3

• The intramuscular route is mandatory in the acute setting because oral and rectal routes are unreliable when patients experience severe pain, nausea, or vomiting. 1, 3

• NSAIDs work by two mechanisms: they provide direct analgesia and decrease ureteral smooth muscle tone and spasm that contribute to stone pain. 3

• NSAIDs reduce the need for additional rescue analgesia by approximately 50% compared to opioid regimens and cause markedly less vomiting (6% versus 20% with opioids). 4, 5

• Alternative NSAIDs include IV ketorolac or IV ibuprofen when intravenous access is available, though the evidence supporting diclofenac remains strongest. 1

Critical Safety Screening Before NSAID Use

• Assess renal function (estimated GFR) before administration because NSAIDs are contraindicated in patients with reduced glomerular filtration rate or pre-existing renal impairment. 1, 3

• Screen for cardiovascular and gastrointestinal risk factors, especially in older adults, as NSAIDs increase the risk of cardiovascular events and GI bleeding; use the lowest effective dose. 1, 3

• In patients older than 60 years, actively exclude a leaking abdominal aortic aneurysm as an alternative cause of flank pain before giving analgesia. 1, 3

• NSAIDs should never be used during pregnancy; morphine carries a lower risk of adverse effects in pregnant women. 4

Second-Line Treatment: Opioids (When NSAIDs Contraindicated)

• Opioids should be reserved exclusively for patients in whom NSAIDs are contraindicated (reduced GFR, significant cardiovascular disease, history of GI bleeding, active peptic ulcer disease) or when NSAIDs fail to control pain within 60 minutes. 1, 2, 3

• Morphine sulfate combined with an antiemetic (cyclizine) is the recommended opioid regimen when opioid therapy is required. 1, 3

• Alternative opioids include hydromorphone, pentazocine, or tramadol, but avoid pethidine because it produces the highest vomiting rate (approximately 74%) and greatest likelihood of requiring supplementary analgesia. 1, 2, 4

• In patients with renal impairment, fentanyl is the only acceptable opioid because it does not generate active metabolites that accumulate in renal failure; never use morphine, codeine, or tramadol in renal failure. 1, 2

Pain Control Timeline and Failure Criteria

• Effective analgesia should achieve pain relief within 30 minutes of administration. 1, 3

• If severe pain persists beyond 60 minutes after appropriate analgesia, immediate hospital admission is mandatory. 1, 2, 3

• Telephone follow-up 1 hour after initial assessment is required to confirm analgesic effectiveness and determine need for admission. 1, 2

• Acceptable pain control must be maintained for at least 6 hours after initial treatment before discharge. 1, 2

Red-Flag Criteria Requiring Immediate Hospital Admission

• Fever or any sign of systemic infection (suggesting sepsis with obstruction) mandates urgent admission, urine cultures, empiric broad-spectrum antibiotics, and immediate decompression via percutaneous nephrostomy or ureteral stenting. 1, 2, 3

• Anuria or severe oliguria (≤1 void in 24 hours) requires urgent admission and decompression. 1, 2, 3

• Hemodynamic shock or instability triggers immediate admission. 1, 3

• Persistent vomiting despite analgesia signals failure of outpatient management. 1

Common Pitfalls to Avoid

• Never use standard opioid dosing protocols in renal failure; always start with lower doses and titrate carefully, preferring fentanyl exclusively. 2

• Do not rely on oral or rectal NSAID administration in acute renal colic; these routes are unreliable when patients have severe pain or nausea. 1, 3

• Avoid pethidine due to its high vomiting rate and frequent need for rescue medication. 1, 2, 4

• Do not discharge patients with unlimited quantities of oral analgesics to prevent misuse. 1

Adjunctive Medical Expulsive Therapy

• Alpha-blockers (tamsulosin) are strongly recommended only for distal ureteral stones larger than 5 mm, as they increase spontaneous passage rates by approximately 50%. 6, 1

• Alpha-blockers are not indicated for stones ≤5 mm because approximately 90% of such small stones pass spontaneously without pharmacologic aid. 1

• Medical expulsive therapy does not replace urgent decompression in cases of anuria, sepsis, or persistent vomiting. 1