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NSAID (non-selective COX inhibitor) Pregnancy: SPC 4.6: Pregnancy - inhibition of prostaglandin synthesis may adversely affect the pregnancy and/or 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 (absolute risk of cardiovascular malformation increased from less than 1% up to approximately 1.5%, believed to increase with dose and duration). If used by a woman attempting to conceive, or during the first and second trimester, the dose should be as low and the duration as short as possible, and diclofenac should not be given in the first and second trimester unless clearly necessary. From the 20th week of pregnancy onward, use may cause oligohydramnios resulting from foetal renal dysfunction (usually reversible on discontinuation); antenatal monitoring for oligohydramnios should be considered after exposure for several days from gestational week 20 onward, and diclofenac should be discontinued if oligohydramnios is found. In the third trimester prostaglandin synthesis inhibitors may expose the foetus to cardiopulmonary toxicity (premature closure of the ductus arteriosus, pulmonary hypertension) and renal dysfunction, and the mother and neonate to possible prolongation of bleeding time and inhibition of uterine contractions; diclofenac is contraindicated during the third trimester. Lactation - passes into breast milk in small amounts and should not be administered during breast feeding. Fertility - may impair female fertility and is not recommended in women attempting to conceive; withdrawal should be considered in women with difficulty conceiving or under investigation for infertility. This summary may be incomplete — check the full SPC.

Diclofenac sodium

Brand names: Voltarol, Diclomax, Voltarol Emulgel

Diclofenac sodium is the standard salt of the NSAID diclofenac, available in oral, modified-release, suppository and parenteral forms for pain and inflammation in arthritis, acute musculoskeletal disorders and postoperative pain.

Adult dose

Dose: Adults, oral (diclofenac sodium 50 mg gastro-resistant tablets) - relief of pain and inflammation in arthritic conditions (rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, acute gout), acute musculo-skeletal disorders (e.g. periarthritis/frozen shoulder, tendinitis, tenosynovitis, bursitis) and other painful conditions resulting from trauma (including fracture, low back pain, sprains, strains, dislocations, orthopaedic, dental and other minor surgery): 75-150 mg daily in two or three divided doses
Route: Oral
Frequency: Daily, in two or three divided doses
Max: 150 mg/day
SOURCE: UK SPC for ONE product - diclofenac sodium 50 mg gastro-resistant (enteric coated) tablets (PL495650088, Rudipharm Limited); each tablet contains diclofenac sodium 50 mg. SPC 4.2 verbatim: 'For oral administration Adults: 75-150mg daily in two or three divided doses. The recommended maximum daily dose of diclofenac is 150mg.' Use the lowest effective dose for the shortest duration necessary to control symptoms (4.2 and 4.4). SCOPE - ORAL TABLETS ONLY: this page lists oral, intramuscular, intravenous, topical (Voltarol Emulgel/gel) and rectal (PR) routes; this SPC covers none of the non-oral routes, so no IM, IV, topical or rectal dose is given here and those products' regimens differ. ELDERLY (4.2): no separate numeric elderly dose is printed; NSAIDs 'should be used with particular caution' in the elderly, 'the lowest effective dosage be used in frail elderly patients or those with a low body weight', and the patient should be monitored for GI bleeding during NSAID therapy. CHILDREN: the SPC states 'Children: Not recommended' (4.1) and 'Paediatric population Not recommended' (4.2), so no paediatric dose is given. Some sections of the product information we used were incomplete — check the full SPC.

Dose adjustments

Renal

Contraindicated in severe renal impairment (4.3). No specific studies in renal impairment, 'therefore, no specific dose adjustment recommendations can be made'; caution is advised in mild to moderate renal impairment (4.2).

Hepatic

Contraindicated in severe hepatic impairment (4.3). No specific studies in hepatic impairment, 'therefore, no specific dose adjustment recommendations can be made'; caution is advised in mild to moderate hepatic impairment (4.2).

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via MHRA Products — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance 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
  • Severe hepatic, renal or cardiac failure
  • Patients in whom attacks of asthma, angioedema, urticaria or acute rhinitis are precipitated by ibuprofen, acetylsalicylic acid or other non-steroidal anti-inflammatory drugs
  • Established congestive heart failure (NYHA II-IV), ischaemic heart disease, peripheral arterial disease and/or cerebrovascular disease

Side effects

  • Gastrointestinal - common: nausea, vomiting, diarrhoea, dyspepsia, abdominal pain, flatulence, anorexia
  • Gastrointestinal - rare: gastritis, gastrointestinal haemorrhage, haematemesis, haemorrhagic diarrhoea, melaena, gastrointestinal ulcer with or without bleeding or perforation (sometimes fatal, particularly in the elderly)
  • Gastrointestinal - very rare: colitis (including haemorrhagic colitis and exacerbation of ulcerative colitis or Crohn's disease), constipation, stomatitis, glossitis, oesophageal disorder, diaphragm-like intestinal strictures, pancreatitis; frequency unknown: ischaemic colitis
  • Nervous system - common: headache, dizziness; vertigo (ear and labyrinth disorders)
  • Skin - common: rash; rare: urticaria; very rare: bullous eruptions, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, exfoliative dermatitis, photosensitivity reaction, purpura
  • Hepatobiliary - common: increased transaminases; rare: hepatitis, jaundice, liver disorder; very rare: fulminant hepatitis, hepatic necrosis, hepatic failure
  • Immune system - rare: hypersensitivity, anaphylactic and anaphylactoid reactions (including hypotension and shock); very rare: angioneurotic oedema
  • Cardiac - very rare: palpitations, chest pain, cardiac failure, myocardial infarction; not known: Kounis syndrome
  • Renal and urinary - very rare: acute renal failure, haematuria, proteinuria, nephrotic syndrome, interstitial nephritis, renal papillary necrosis
  • Blood - very rare: thrombocytopenia, leucopoenia, anaemia (including haemolytic and aplastic anaemia), agranulocytosis

Interactions

  • Lithium: diclofenac may increase plasma lithium concentrations - monitor serum lithium
  • Digoxin: diclofenac may raise plasma digoxin concentrations - monitor serum digoxin
  • Diuretics and antihypertensives (beta-blockers, ACE inhibitors): reduced antihypertensive effect; ensure adequate hydration and consider renal function monitoring, particularly with diuretics and ACE inhibitors (increased risk of nephrotoxicity)
  • Potassium-sparing diuretics, ciclosporin, tacrolimus, trimethoprim: increased serum potassium - monitor frequently
  • Anticoagulants and anti-platelet agents: increased risk of bleeding - close monitoring
  • Other systemic NSAIDs (including COX-2 inhibitors) and corticosteroids: increased risk of gastrointestinal bleeding or ulceration - avoid concomitant use of two or more NSAIDs
  • SSRIs: increased risk of gastrointestinal bleeding

Monitoring

  • Monitor for GI bleeding during NSAID therapy, particularly in frail elderly patients or those with a low body weight (4.2)
  • Regular monitoring of hepatic function during prolonged treatment; discontinue if abnormal liver function tests persist or worsen (4.4)
  • Monitor renal function as a precaution in patients with impaired cardiac or renal function, hypertension, the elderly, those on diuretics or other renal-impacting medicines, and those with extracellular volume depletion (4.4)
  • Periodically monitor blood pressure when used with diuretics or antihypertensive agents, especially in the elderly (4.5)
  • Monitor serum lithium and serum digoxin levels if used concomitantly (4.5)
  • Close medical surveillance in patients with a history suggestive of gastrointestinal ulceration, bleeding or perforation, and in ulcerative colitis or Crohn's disease (4.4)

Clinical monograph

How it works

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

Prescribing in practice

  • Diclofenac is associated with a higher risk of arterial thrombotic events and is contraindicated in ischaemic heart disease, cerebrovascular disease, peripheral arterial disease and heart failure (MHRA); restrict to the lowest effective dose for the shortest time.
  • Provide gastroprotection in those at gastrointestinal risk and avoid concurrent use of other NSAIDs.
  • Use caution in renal impairment, hypertension, asthma and the elderly, and avoid in the third trimester of pregnancy.

Monitoring

Review blood pressure, renal function and gastrointestinal tolerance during treatment, especially on prolonged courses or in higher-risk patients.

Counselling the patient

  • Take with or after food.
  • Report black or tarry stools, indigestion that does not settle, or any chest pain or breathlessness.
  • Avoid taking other anti-inflammatory painkillers at the same time unless advised.

Evidence & guidelines

Diclofenac sodium is an established NSAID; its efficacy and cardiovascular/gastrointestinal risk profile are documented in MHRA reviews and NICE osteoarthritis and analgesia guidance.

Reference: NICE NG100; NICE CKS NSAIDs; MHRA Drug Safety Update; 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.

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