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NSAID (Non-Steroidal Anti-Inflammatory Drug) 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

Brand names: Voltarol, Diclomax

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) used for pain and inflammation; in older people it requires particular caution because of cumulative cardiovascular, gastrointestinal and renal risks.

Adult dose

Dose: Adults including the elderly, 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. In the elderly the lowest effective dosage should be used, particularly in frail elderly patients or those with a low body weight
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.' ELDERLY - THE SPC PRINTS NO SEPARATE NUMERIC ELDERLY DOSE and no automatic dose reduction. 4.2: 'Although the pharmacokinetics of diclofenac are not impaired to any clinically relevant extent in elderly patients, nonsteroidal anti-inflammatory drugs should be used with particular caution in such patients who generally are more prone to adverse reactions. In particular it is recommended that 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.' 4.4: the elderly have increased frequency of adverse reactions to NSAIDs, especially gastrointestinal bleeding and perforation which may be fatal; in patients with a history of ulcer and in the elderly treatment should be initiated and maintained at the lowest effective dose, and combination therapy with a protective agent (e.g. misoprostol or a proton pump inhibitor) should be considered for those patients and for patients requiring concomitant low-dose aspirin or other medicinal products likely to increase gastrointestinal risk. SCOPE - ORAL ONLY: this page also lists a topical route; this SPC does not cover topical diclofenac, so no topical dose is given and that product's regimen differs. 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). Particular caution for fluid retention and oedema in patients with impaired cardiac or renal function, history of hypertension, the elderly, those on diuretics, and those with extracellular volume depletion; monitoring of renal function is recommended as a precaution (4.4).

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; patients, especially the elderly, should have blood pressure periodically monitored, be adequately hydrated, and renal function should be considered for monitoring (increased risk of nephrotoxicity with diuretics and ACE inhibitors)
  • 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)
  • Patients with a history of GI toxicity, particularly when elderly, should report any unusual abdominal symptoms, especially GI bleeding (4.4)
  • 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)

Clinical monograph

How it works

It inhibits cyclo-oxygenase (COX-1 and COX-2), reducing prostaglandin synthesis and thereby decreasing inflammation, pain and fever.

Prescribing in practice

  • In older patients the cardiovascular, gastrointestinal bleeding and renal risks are amplified; diclofenac carries a relatively high cardiovascular risk and is generally avoided, with the lowest effective dose for the shortest time if used and gastroprotection considered.
  • Avoid or use great caution with concurrent anticoagulants, antiplatelets, ACE inhibitors/ARBs, diuretics and other NSAIDs, and in heart failure, peptic ulcer disease or significant renal impairment.
  • It is contraindicated in established ischaemic heart disease, cerebrovascular disease, peripheral arterial disease and heart failure.

Monitoring

Monitor renal function and blood pressure, and watch for gastrointestinal and cardiovascular symptoms, especially in dehydrated or polypharmacy patients.

Counselling the patient

  • Take with or after food and report any black stools, vomiting blood or indigestion promptly.
  • Do not combine with other anti-inflammatory painkillers, including over-the-counter ones.
  • Use for the shortest time needed and report ankle swelling, breathlessness or reduced urine output.

Evidence & guidelines

MHRA advice and large cardiovascular safety reviews confirm diclofenac carries an elevated thrombotic risk comparable to some COX-2 inhibitors, supporting restricted use in older and at-risk patients.

Reference: MHRA Drug Safety Update 2013 (diclofenac cardiovascular risk); AGS Beers Criteria 2023; STOPP/START v3; NICE CG177; 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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