NSAID — Perioperative Analgesia Pregnancy: Avoid in third trimester; use with caution in earlier pregnancy

Diclofenac (Perioperative)

Brand names: Voltarol, Diclofenac SR

Adult dose

Dose: 75 mg IM (single pre-operative dose) or 50 mg oral three times daily

Route: Intramuscular / Oral / Rectal (75-100 mg PR)

Frequency: IM: single dose; Oral/PR: two to three times daily

Max: 150 mg/day

Pre-operative IM diclofenac 75 mg: analgesic onset 30-60 min, duration 8-12 hours. PR diclofenac 100 mg useful post-operatively when oral route not established. Deep IM injection into gluteal muscle

Paediatric dose

Dose: 1-3 mg/kg/day in divided doses (oral/PR) mg/day/kg

Route: Oral / Rectal

Frequency: Two to three times daily

Max: 3 mg/kg/day

Child 6 months to 17 years: 1-3 mg/kg/day. Not licensed under 6 months. IM route not recommended in children

Dose adjustments

Renal

Avoid if eGFR under 30

Hepatic

Avoid in severe hepatic impairment

Paediatric weight-based calculator

Patient weight (kg)

Child 6 months to 17 years: 1-3 mg/kg/day. Not licensed under 6 months. IM route not recommended in children

Clinical pearls

MHRA 2013: Diclofenac carries equivalent cardiovascular risk to COX-2 inhibitors (celecoxib) — contraindicated in established ischaemic heart disease, heart failure, or peripheral arterial disease
Pre-operative IM diclofenac: evidence-based as part of pre-emptive multimodal analgesia — reduces intraoperative opioid requirements and PACU pain scores
PR diclofenac 100 mg post-operatively: useful when patient recovering from anaesthesia and oral route not yet established; higher bioavailability than oral
Bone healing: preclinical evidence suggests NSAIDs may impair fracture healing; clinical significance debated; many orthopaedic surgeons avoid NSAIDs post-fracture fixation — consider alternatives in these patients
Topical diclofenac (Voltarol gel): minimal systemic absorption; safe option for localised post-operative musculoskeletal pain without systemic NSAID risks

Contraindications

Established cardiovascular disease (MHRA 2013)
Active GI ulceration
Severe renal or hepatic impairment
Aspirin-sensitive asthma
Third trimester of pregnancy

Side effects

GI ulceration and bleeding
Renal impairment (AKI)
Cardiovascular events
Hepatotoxicity
Pain at IM injection site

Interactions

Anticoagulants (increased bleeding)
ACEi + diuretics (triple whammy AKI)
Lithium (increased levels)
Methotrexate (reduced excretion)

Monitoring

Renal function
Blood pressure
GI symptoms
Signs of bleeding

Reference: BNFc; BNF 90; MHRA Drug Safety Update 2013; PROSPECT Guidelines; BNF 90. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways