Skip to content
ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
NSAID — Perioperative Analgesia Pregnancy: Inhibition of prostaglandin synthesis may adversely affect the pregnancy and/or the embryo/foetal development. Epidemiological data suggest an increased risk of miscarriage and of cardiac malformation and gastroschisis after use of a prostaglandin synthesis inhibitor in early pregnancy; the absolute risk for cardiovascular malformation was increased from less than 1% up to approximately 1.5%, and is believed to increase with dose and duration of therapy. From the 20th week of pregnancy onward, Voltarol use may cause oligohydramnios resulting from foetal renal dysfunction, and ductus arteriosus constriction has been reported following treatment in the second trimester. During the first and second trimester, Voltarol should not be given unless clearly necessary; if used by a woman attempting to conceive, or in the first or second trimester, the dose should be kept as low and the duration as short as possible. Antenatal monitoring for oligohydramnios and ductus arteriosus constriction should be considered after exposure for several days from gestational week 20 onward, and Voltarol discontinued if either is found. During the third trimester all prostaglandin synthesis inhibitors may expose the foetus to cardiopulmonary toxicity and renal dysfunction, and the mother and neonate to possible prolongation of bleeding time and inhibition of uterine contractions resulting in delayed or prolonged labour. Consequently Voltarol is contraindicated during the third trimester. Lactation: diclofenac passes into breast milk in small amounts and should not be administered during breast feeding. Fertility: the use of diclofenac may impair female fertility and is not recommended in women attempting to conceive; withdrawal should be considered in women who have difficulty conceiving or are undergoing investigation of infertility. (Section 4.6 text is truncated at source after this point.)

Diclofenac (Perioperative)

Brand names: Voltarol, Diclofenac SR

Diclofenac is a non-steroidal anti-inflammatory drug used perioperatively for moderate postoperative pain and as part of opioid-sparing multimodal analgesia.

Adult dose

Dose: Post-operative pain (acute pain, intramuscular): one 75 mg ampoule intramuscularly by deep intragluteal injection into the upper outer quadrant
Route: Intramuscular
Frequency: Once daily (in severe cases twice daily); if two injections daily are required, use the alternative buttock for the second
Max: 150 mg daily (SPC: 'up to the maximum daily dosage of 150mg')
The pinned product, Voltarol Ampoules (eMC product 1043), is licensed in section 4.1 for IM use in 'acute forms of pain, including ... post-operative pain', so the perioperative use is covered by the label. ROUTES THIS CARD DOES NOT COVER: oral and rectal - neither is in this ampoule SPC and no figure is given for them. The SPC separately licenses diluted intravenous infusion for treatment or prevention of post-operative pain in hospital; that route is not among this page's listed routes, so no IV dose is carded here ('Voltarol must not be given as an intravenous bolus injection'). Duration: 'Voltarol ampoules (given im or iv) should not be given for more than two days; if necessary, treatment can be continued with Voltarol tablets or suppositories.' The SPC also states 'one ampoule of 75mg can be combined with other dosage forms of Voltarol (tablets or suppositories) up to the maximum daily dosage of 150mg'. The directions for intramuscular injection 'must be adhered to in order to avoid damage to a nerve or other tissue at the injection site'. Undesirable effects may be minimised by using the lowest effective dose for the shortest duration necessary to control symptoms. SPC 4.4 cautions on use after gastrointestinal surgery (increased risk of gastro-intestinal anastomotic leak: close medical surveillance and caution) and in patients with substantial extracellular volume depletion, e.g. before or after major surgery. Elderly: lowest effective dosage in frail elderly or low body weight, monitor for GI bleeding. Paediatric: 'Voltarol ampoules are not recommended for use in children.'

Dose adjustments

Renal

Contraindicated in renal failure (SPC 4.2/4.3). 'No specific studies have been carried out in patients with renal impairment, therefore, no specific dose adjustment recommendations can be made. Caution is advised when administering diclofenac to patients with mild to moderate renal impairment.' SPC 4.4: particular caution in patients with impaired cardiac or renal function, hypertension, the elderly, those on diuretics or other medicinal products that can significantly impact renal function, and those with substantial extracellular volume depletion from any cause, e.g. before or after major surgery; monitoring of renal function is recommended in such cases. For intravenous use specifically (not this card's route): moderate or severe renal impairment (serum creatinine >160 µmol/l) and hypovolaemia or dehydration from any cause are contraindications.

Hepatic

Contraindicated in hepatic failure (SPC 4.2/4.3). 'No specific studies have been carried out in patients with hepatic impairment, therefore, no specific dose adjustment recommendations can be made. Caution is advised when administering diclofenac to patients with mild to moderate hepatic impairment.' SPC 4.4: close medical surveillance is required in patients with impaired hepatic function.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance, sodium metabisulphite or any of the excipients
  • Active gastric or intestinal ulcer, bleeding or perforation
  • History of gastrointestinal bleeding or perforation relating to previous NSAID therapy
  • Active, or history of recurrent, peptic ulcer/haemorrhage (two or more distinct episodes of proven ulceration or bleeding)
  • Last trimester of pregnancy
  • Hepatic failure
  • Renal failure
  • Established congestive heart failure (NYHA II-IV), ischaemic heart disease, peripheral arterial disease and/or cerebrovascular disease
  • Patients in whom attacks of asthma, angioedema, urticaria or acute rhinitis are precipitated by ibuprofen, acetylsalicylic acid or other NSAIDs
  • Specifically for intravenous use (not this card's route): concomitant NSAID or anticoagulant use (including low dose heparin); history of haemorrhagic diathesis or confirmed/suspected cerebrovascular bleeding; operations associated with a high risk of haemorrhage; a history of asthma; moderate or severe renal impairment (serum creatinine >160 µmol/l); hypovolaemia or dehydration from any cause

Side effects

  • Common: headache, dizziness, vertigo
  • Common: nausea, vomiting, diarrhoea, dyspepsia, abdominal pain, flatulence, anorexia
  • Common: transaminases increased; rash
  • Rare: hypersensitivity, anaphylactic and anaphylactoid reactions (including hypotension and shock); urticaria; asthma (including dyspnoea); hepatitis, jaundice, liver disorder; somnolence, tiredness
  • Gastrointestinal haemorrhage, haematemesis, melaena and gastrointestinal ulcer with or without bleeding or perforation (sometimes fatal, particularly in the elderly)
  • Uncommon (cardiac): myocardial infarction, cardiac failure, palpitations, chest pain; Kounis syndrome (not known)
  • Injection site abscess (very rare); injection site necrosis (not known); the SPC 4.4 also warns that incorrect intramuscular injection may cause muscle weakness, muscle paralysis, hypoaesthesia and embolia cutis medicamentosa (Nicolau syndrome)
  • Very rare: thrombocytopenia, leucopoenia, anaemia (including haemolytic and aplastic), agranulocytosis; angioneurotic oedema; hypertension, hypotension, vasculitis; fulminant hepatitis, hepatic necrosis, hepatic failure
  • Very rare: Stevens-Johnson syndrome, toxic epidermal necrolysis, bullous eruptions, exfoliative dermatitis; acute renal failure, haematuria, proteinuria, nephrotic syndrome

Interactions

  • Concomitant use with systemic NSAIDs, including cyclooxygenase-2 selective inhibitors, should be avoided (no evidence of synergistic benefit; additive undesirable effects)
  • Caution with medications that increase the risk of ulceration or bleeding: systemic corticosteroids, anticoagulants such as warfarin, SSRIs, anti-platelet agents such as acetylsalicylic acid
  • Combination therapy with a protective agent (e.g. misoprostol or a proton pump inhibitor) should be considered for patients with a history of ulcer, the elderly, and those needing concomitant low dose aspirin or medicinal products likely to increase gastrointestinal risk
  • Diuretics and medicinal products that can significantly impact renal function: particular caution; monitor renal function
  • For intravenous use specifically: concomitant NSAID or anticoagulant use (including low dose heparin) is contraindicated

Monitoring

  • Monitor for GI bleeding during NSAID therapy, particularly in the elderly; withdraw the drug if gastrointestinal bleeding or ulceration occurs
  • After gastrointestinal surgery: close medical surveillance and caution (NSAIDs may increase the risk of gastro-intestinal anastomotic leak)
  • Monitoring of renal function is recommended in patients with impaired cardiac or renal function, hypertension, the elderly, those on diuretics, and those with extracellular volume depletion, e.g. before or after major surgery
  • Regular monitoring of hepatic function during prolonged treatment; discontinue if abnormal liver function tests persist or worsen or clinical signs of liver disease develop
  • Follow the intramuscular injection instructions strictly (deep intragluteal injection, upper outer quadrant, alternate buttock for a second daily injection) to avoid nerve or tissue damage and injection site necrosis
  • Diclofenac may mask the signs and symptoms of infection
  • Be alert to hypersensitivity reactions, which can progress to Kounis syndrome (chest pain with an allergic reaction)

Clinical monograph

How it works

It inhibits cyclo-oxygenase (COX-1 and COX-2), reducing prostaglandin synthesis to produce analgesic and anti-inflammatory effects.

Prescribing in practice

  • Avoid in patients with renal impairment, hypovolaemia or significant cardiovascular disease, as perioperative NSAIDs risk acute kidney injury and diclofenac carries the highest cardiovascular thrombotic risk of the traditional NSAIDs.
  • It increases gastrointestinal and surgical-site bleeding risk through platelet inhibition and mucosal injury, so consider gastroprotection and the procedure's bleeding profile.
  • Avoid in active peptic ulceration, severe heart failure and in those with aspirin- or NSAID-sensitive asthma.

Monitoring

Monitor renal function, blood pressure, fluid balance and for signs of gastrointestinal or surgical bleeding.

Counselling the patient

  • Take with or after food and report indigestion, black stools or reduced urine output.
  • Avoid other anti-inflammatory painkillers at the same time.

Evidence & guidelines

Perioperative NSAID use for opioid-sparing analgesia is supported by NICE acute pain guidance, with cardiovascular cautions reflecting MHRA advice.

Reference: MHRA Drug Safety Update 2013; PROSPECT Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Pathways