What is the first‑line treatment for acute renal colic pain from a kidney stone, and what are the alternatives if NSAIDs are contraindicated?

Treatment of Kidney Stone Pain

First-Line Treatment: NSAIDs

Intramuscular diclofenac 75 mg is the first-line treatment for acute renal colic pain, providing superior pain relief compared to opioids while causing fewer side effects. 1, 2

Why NSAIDs Work Best

• NSAIDs directly address the pathophysiology of renal colic by providing analgesia and decreasing ureteral smooth muscle tone and spasm that contribute to kidney stone pain 1
• NSAIDs reduce the need for additional analgesia compared to opioids and cause significantly fewer adverse effects, particularly less vomiting (6% vs 20% with opioids) 3, 4
• Pain relief should occur within 30 minutes of administration 5, 2

Optimal Route and Dosing

• Intramuscular injection is the preferred route because oral and rectal administration are unreliable in acute settings, and intravenous routes are often impractical 5, 2
• Diclofenac 75 mg IM is specifically recommended as the initial analgesic when the diagnosis is clear and no contraindications exist 1, 2
• Alternative NSAIDs with strong evidence include ibuprofen IV or ketorolac IV, though diclofenac IM has the most robust data 4

Critical NSAID Contraindications

Screen carefully before prescribing NSAIDs in these high-risk situations:

• Severe renal impairment or low glomerular filtration rate 1, 6
• Heart failure or renal artery stenosis 3
• Dehydration or concurrent nephrotoxic drug use 3
• Very elderly patients 3
• Pregnancy (NSAIDs are absolutely contraindicated) 3
• Use the lowest effective dose due to cardiovascular and gastrointestinal risks 1

Second-Line Treatment: Opioids

Reserve opioids exclusively for patients with NSAID contraindications or when NSAIDs fail to control pain within one hour. 1, 6, 2

Preferred Opioid Agents

• Morphine sulfate combined with an antiemetic (such as cyclizine) is recommended when opioids are necessary 5, 6
• Alternative opioids include hydromorphone, pentazocine, or tramadol 1, 6
• Avoid pethidine due to higher rates of vomiting and need for additional analgesia 1, 6

Special Considerations for Renal Impairment

• Fentanyl is the preferred opioid in renal failure because it does not accumulate active metabolites 6
• Never use morphine, codeine, or tramadol as first-line agents in renal impairment 6, 2
• Always start with lower doses in renal failure and titrate carefully 6

Opioid Safety Measures

• Assess risk of substance abuse before prescribing and obtain informed consent 1
• Monitor for respiratory depression and confusion 2
• Expect vomiting in approximately 20% of patients receiving opioids 3

Combination Therapy

• Adding an NSAID to morphine provides greater analgesic effect than either agent alone in approximately 10% of patients 3
• Combination therapy is an alternative choice for uncontrolled pain after initial NSAID use 4
• However, combination therapy causes more adverse events overall 4

Pain Control Timeline and Admission Criteria

Strict time-based protocols prevent complications:

• Analgesia must provide pain relief within 30 minutes of administration 5, 2
• If severe pain does not remit within 60 minutes, immediately admit the patient to hospital 5, 6, 2
• Follow up with a telephone call one hour after initial assessment to check analgesic effectiveness 5, 6
• Complete or acceptable pain control should be maintained for at least six hours 5, 6

Immediate Hospital Admission Required For:

• Fever or signs of systemic infection (possible sepsis) 5, 2
• Shock or hemodynamic instability 5, 2
• Anuria in an obstructed kidney 2
• Failure to respond to analgesia within 60 minutes 5, 2
• Abrupt recurrence of severe pain 5

Urgent Decompression Indications

• Sepsis and/or anuria in an obstructed kidney requires urgent decompression via percutaneous nephrostomy or ureteral stenting 6, 2

Adjunctive Measures

• Instruct patients to increase fluid intake significantly to facilitate stone passage 1, 2
• Have patients strain urine through a tea strainer or gauze to catch any identifiable calculus for analysis 5, 2
• Medical expulsive therapy with alpha-blockers (tamsulosin) may be beneficial for stones >5 mm in the distal ureter 6, 2

Common Pitfalls to Avoid

NSAID-related errors:

• Failing to screen for renal impairment before prescribing NSAIDs 1, 2
• Using NSAIDs in elderly patients with multiple cardiovascular comorbidities without considering risks 2
• Prescribing NSAIDs during pregnancy 3

Opioid-related errors:

• Using standard opioid dosing protocols in renal failure 6, 2
• Choosing pethidine as first-line opioid 1, 6
• Prescribing morphine, codeine, or tramadol in patients with renal impairment 6, 2

Management errors:

• Attempting further outpatient management after 60 minutes of failed analgesia 2
• Missing signs of sepsis (fever with obstruction constitutes a urological emergency) 2
• Failing to rule out leaking abdominal aortic aneurysm in patients over 60 years 5, 2