Best Pain Medicine for Biliary Colic
Intramuscular diclofenac 75 mg is the first-line treatment for biliary colic when the diagnosis is clear and there are no contraindications. 1
First-Line Treatment: NSAIDs
Diclofenac 75 mg intramuscularly is the recommended initial analgesic, providing rapid and effective pain relief within 30 minutes of administration. 1 This recommendation is supported by multiple high-quality studies demonstrating superior efficacy compared to other analgesics:
- NSAIDs achieve complete pain relief in 91.7% of patients at 4 hours, compared to only 69.4% with spasmolytic drugs like hyoscine (P = 0.037). 2
- NSAIDs reduce the risk of progression to acute cholecystitis by 73% (RR 0.27,95% CI 0.12-0.57) compared to spasmolytic drugs. 3
- Compared to placebo, NSAIDs achieve a 3.77-fold higher rate of complete pain relief (RR 3.77,95% CI 1.65-8.61) and reduce complications by 47% (RR 0.53,95% CI 0.31-0.89). 4
Why Intramuscular Route?
The intramuscular route is preferred because oral and rectal administration are unreliable during acute biliary colic, and intravenous access may be impractical in certain settings. 1
Second-Line Treatment: Opioids
When NSAIDs are contraindicated (renal impairment, peptic ulcer disease, bleeding disorders, NSAID allergy), use an opioid combined with an antiemetic. 1 The recommended combination is morphine sulfate with cyclizine. 1
Important Caution with Opioids
Morphine can cause spasm of the sphincter of Oddi and increase biliary tract pressure, which is a significant concern in biliary colic. 5 Despite this theoretical disadvantage, clinical trials show NSAIDs and opioids have similar efficacy for pain control (RR 0.98,95% CI 0.47-2.07), though NSAIDs remain preferred due to their additional benefit of reducing complications. 3
Treatment Algorithm
Immediate assessment: Confirm biliary colic diagnosis and exclude complications (fever, shock, jaundice). 1
First-line: Administer diclofenac 75 mg IM if no contraindications exist. 1
Monitor at 60 minutes: If pain persists or worsens, arrange immediate hospital admission. 1
Alternative if NSAIDs contraindicated: Give morphine sulfate with cyclizine (antiemetic). 1
Follow-up: Contact patient by telephone 1 hour after initial treatment to assess response. 1
Critical Red Flags Requiring Immediate Hospital Admission
- Shock or fever present at initial assessment 1
- Severe pain not relieved within 60 minutes of initial analgesia 1
- Abrupt recurrence of severe pain after initial improvement 1
Additional Management Considerations
Complete or acceptable pain control should be maintained for at least 6 hours. 1 Patients should be instructed to drink plenty of fluids and void urine into a container to catch any identifiable calculus. 1
Common Pitfalls to Avoid
- Do not delay analgesia while waiting for diagnostic imaging. Pain relief should be provided within 30 minutes of assessment. 1
- Do not use spasmolytic drugs (hyoscine) as first-line treatment. They are significantly less effective than NSAIDs for both pain control and preventing progression to acute cholecystitis. 2, 3
- Do not issue limited quantities of oral or rectal analgesics for recurrent pain due to unreliable absorption and potential for drug misuse. 1
- In elderly patients (>60 years), consider alternative diagnoses such as leaking abdominal aortic aneurysm before attributing pain solely to biliary colic. 1
Evidence Quality Note
The recommendation for diclofenac is based on moderate-quality evidence from multiple randomized controlled trials and systematic reviews. 3, 4 The Cochrane systematic review (2016) found moderate-quality evidence for NSAIDs versus placebo, though noted that most trials excluded elderly patients and those with comorbidities, potentially limiting generalizability. 3