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NSAID — Renal / Ureteric Colic Pregnancy: Avoid in third trimester; use with caution in first and second trimesters

Diclofenac

Brand names: Voltarol, Dyloject (IV)

Adult dose

Dose: 75 mg IM or IV; or 100 mg PR (suppository)
Route: Intramuscular / Intravenous / Rectal
Frequency: As required; may repeat after 30 minutes (IV); maximum twice daily
Max: 150 mg/day parenteral
First-line analgesia for acute renal colic in ED. IV formulation (Dyloject) can be given over 15 seconds bolus or as infusion. Equally effective to opioids for ureteric colic with fewer side effects

Paediatric dose

Dose: 1-3 mg/kg/day in divided doses mg/day/kg
Route: Oral / PR
Frequency: Two to three times daily
Max: 3 mg/kg/day
Seek specialist opinion for acute renal colic in children — IV diclofenac not routinely used in paediatric ED; ibuprofen preferred

Dose adjustments

Renal

Use with caution in mild-moderate renal impairment; avoid if eGFR under 30 — NSAIDs reduce renal prostaglandins, worsening pre-existing renal impairment

Hepatic

Avoid in severe hepatic impairment

Paediatric weight-based calculator

Seek specialist opinion for acute renal colic in children — IV diclofenac not routinely used in paediatric ED; ibuprofen preferred

Clinical pearls

  • RCEM and EAU guidelines: diclofenac is first-line analgesia for ureteric colic — equivalent to opioids with fewer side effects (no nausea, sedation, or dependence risk)
  • Hydration status critical in stone patients — NSAIDs can cause AKI in dehydrated patients; ensure adequate IV fluids alongside diclofenac in ED
  • PR diclofenac 100 mg: useful when IV access unavailable; equally effective to IM/IV in acute colic
  • MHRA 2013: Diclofenac has similar cardiovascular risk to COX-2 inhibitors — avoid in patients with ischaemic heart disease, heart failure, or peripheral arterial disease
  • Medical expulsive therapy (MET): tamsulosin 400 micrograms once daily aids spontaneous passage of distal ureteric stones under 10 mm — prescribe alongside analgesia in ED

Contraindications

  • eGFR under 30
  • Established cardiovascular disease (MHRA 2013)
  • Active peptic ulcer or GI bleeding
  • Aspirin-sensitive asthma
  • Third trimester of pregnancy

Side effects

  • GI ulceration and bleeding
  • Renal impairment (AKI — risk with dehydrated stone patient)
  • Cardiovascular events
  • Hepatotoxicity
  • Pain at IM injection site

Interactions

  • Warfarin / DOACs (increased bleeding risk)
  • ACEi + diuretics (triple whammy — AKI risk)
  • Lithium (increases levels)
  • Methotrexate (reduces excretion)

Monitoring

  • Pain score (NRS)
  • Renal function (U&E — if prolonged use or dehydration)
  • GI symptoms

Reference: BNFc; BNF 90; RCEM Clinical Standards for Emergency Analgesia; EAU Urolithiasis Guidelines 2024; MHRA 2013. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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