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Diclofenac potassium oral

Updated 2 Feb 2023 | NSAIDs


Oral formulations of diclofenac potassium.

Drugs List

  • diclofenac potassium 25mg tablets
  • diclofenac potassium 50mg tablets
  • VOLTAROL RAPID 50mg tablets
  • Therapeutic Indications


    Migraine (attack)
    Pain and/or inflammation
    Treatment of post-operative pain

    Unlicensed Uses

    Fever in ear, nose or throat infection



    75mg to 150mg a day, in two or three divided doses.

    Initial dose: 50mg at the first signs or symptoms of an impending attack.
    If the first dose is not sufficient, a further 50mg may be administered after 2 hours.
    50mg may be administered every 4 to 6 hours, if needed.
    Maximum dose should not exceed 200mg a day.


    Children aged 14 to 18 years
    75mg to 100mg a day, in two or three divided doses.

    Children aged 9 to 14 years with a bodyweight of 35kg or more (unlicensed)
    In post-operative pain, up to 2mg/kg may be administered, in 3 divided doses, a day. Maximum dose of 100mg daily.

    Pyrexia due to infection of ear, nose or throat (unlicensed)
    Children aged 9 to 18 years with a bodyweight of 35kg or more
    Up to 2mg/kg in 3 divided doses a day. Maximum dose of 100mg daily.


    Children under 9 years
    Cerebrovascular disorder
    Gastrointestinal haemorrhage
    Gastrointestinal perforation
    Gastrointestinal ulcer
    History of gastrointestinal haemorrhage
    History of peptic ulcer
    Ischaemic heart disease
    New York Heart Association class II failure
    Peripheral arterial circulatory disorder
    Renal impairment - glomerular filtration rate below 10ml/minute
    Severe hepatic impairment
    Third trimester of pregnancy

    Precautions and Warnings

    Allergic disposition
    Females attempting to conceive
    Risk factors for cardiovascular disorder
    Connective tissue disorder
    Crohn's disease
    First trimester of pregnancy
    Glucose-galactose malabsorption syndrome
    Haematological disorder
    Hepatic impairment
    Hereditary fructose intolerance
    New York Heart Association class I failure
    Renal impairment - glomerular filtration rate 10-20ml/minute
    Second trimester of pregnancy
    Systemic lupus erythematosus
    Ulcerative colitis

    May mask symptoms or signs of infections
    May precipitate bronchospasm in patients with asthma or allergy
    Advise patient dizziness may affect ability to drive or operate machinery
    Not all available brands are licensed for all age groups
    Not all available brands are licensed for all indications
    Some formulations contain sucrose
    Some products may contain soya or soya derivative
    Discontinue if signs of gastro-intestinal bleeding occur
    May inhibit platelet aggregation - observe for signs of bleeding
    Monitor hepatic function on long term therapy
    Monitor renal function in patients with hepatic impairment
    Monitor renal function on long term therapy
    Perform blood counts on prolonged use of this treatment
    Advise patient to inform their physician if dyspnoea/chest pain occur
    Advise patient to report gastrointestinal signs or symptoms
    High dose/long term use may increase risk of arterial thrombotic events
    Severe gastro-intestinal side effects may occur without warning
    Discontinue treatment if rash occurs
    Dose varies with brand
    Maintain treatment at the lowest effective dose

    Elderly patients have increased frequency of adverse reactions, especially gastrointestinal bleeding and perforation which may be fatal. These patients should commence treatment on the lowest dose available and be monitored for gastrointestinal bleeding for 4 weeks following initiation of therapy.

    Patients with renal or hepatic impairment and the elderly should be kept under surveillance, since the use of NSAIDs may result in deterioration of renal function. The lowest effective dose should be used and renal function monitored.

    If abnormal liver function tests persist or worsen, clinical signs or symptoms consistent with liver disease develop, or if other manifestations occur (eosinophilia, rash, etc) treatment should be discontinued. Hepatitis may occur without prodromal symptoms.

    Diclofenac potassium may reversibly inhibit platelet aggregation. Patients with defects of haemostasis, bleeding diathesis or haematological abnormalities should be carefully monitored.

    Pregnancy and Lactation


    Diclofenac potassium is contraindicated during the third trimester of pregnancy but may be used with caution during the first and second trimester.

    The manufacturer does not recommend this product during pregnancy.

    First trimester exposure to NSAIDs has been associated with an increased risk spontaneous abortions and of birth defects (notably cardiac septal defects). There is conflicting evidence, however, from various studies and the risk appears to be low.

    When an NSAID is considered essential, a more established drug such as ibuprofen may be considered. Diclofenac should be used with caution in the first and second trimesters. Schaefer (2007) considers that use of NSAIDs in early pregnancy does not require termination of pregnancy or invasive diagnostic procedures.

    Diclofenac is a prostaglandin synthetase inhibitor and may have the following effects during the second and third trimesters:
    - Pulmonary and cardiac toxicity in the foetus/newborn (pulmonary hypertension with preterm closing of the ductus arteriosus). The risk exists from the beginning of the sixth month and increases if administration is close to full term.
    - Functional renal injury in the foetus. From the twelfth week: oligohydramnios (usually reversible after the end of treatment) or anamnios (particularly with prolonged exposure). Following birth, renal failure may persist (especially with late and prolonged exposure).
    - Inhibition of uterine contractions with delayed onset and prolongation of labour.
    - Increased possibility of bleeding in mother and child.
    - Increased risk of maternal oedema formation.
    - When used in the peri-natal period, necrotising enterocolitis and intraventricular haemorrhages have been reported in very pre-term and very low birth weight infants.


    Use diclofenac potassium with caution during breastfeeding.

    The manufacturer does not recommend breastfeeding whilst taking diclofenac potassium.

    In limited studies so far available, NSAIDs can appear in breast milk in very low concentrations.

    When an NSAID is considered necessary during breastfeeding ibuprofen or flurbiprofen would be the drugs of choice although occasional use of diclofenac is permissible.

    The secretion in maternal milk following oral administration is minimal and probably too low to affect the infant. Diclofenac has a short half-life of 1.1 hours and a number of active metabolites although the clinical significance of these is not known.

    Side Effects

    Abdominal pain
    Abnormal liver function
    Acute renal insufficiency
    Aggravation of existing asthma
    Anaphylactoid reaction
    Aphthous stomatitis
    Aplastic anaemia
    Arterial thrombosis
    Aseptic meningitis
    Cerebrovascular accident
    Chest pain
    Colonic stricture
    Congestive cardiac failure
    Diarrhoea - bloody
    Disturbances of sensation
    Exacerbation of colitis or Crohn's proctocolitis
    Gastro-intestinal perforation
    Gastro-intestinal ulceration
    Gastrointestinal bleeding
    Haemolytic anaemia
    Hair loss
    Hearing disturbances
    Hepatic failure
    Hepatic impairment
    Hepatic necrosis
    Hypersensitivity reactions
    Increases in hepatic enzymes
    Interstitial nephritis
    Ischaemic colitis
    Kounis syndrome
    Lyell's syndrome
    Memory disturbances
    Myocardial infarction
    Nephrotic syndrome
    Non-specific allergic reactions
    Non-specific haemorrhagic colitis
    Oesophageal lesions
    Papillary necrosis
    Psychotic symptoms
    Renal failure
    Skin disorder
    Stevens-Johnson syndrome
    Taste disturbances
    Ulcerative stomatitis
    Visual disturbances


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: November 2019

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Summary of Product Characteristics: Diclofenac potassium 25 mg tablets. Accord UK ltd. Revised July 2018.
    Summary of Product Characteristics: Diclofenac potassium 50 mg tablets. Accord UK ltd. Revised July 2018.

    Summary of Product Characteristics: Voltarol Rapid tablets 50mg. Novartis Pharmaceuticals UK Ltd. Revised September 2019.

    The Renal Drug Handbook. 3rd edition. (2009) ed. Ashley, C and Currie, Radcliffe Publishing Ltd, Abingdon.

    'PRAC recommends the same cardiovascular precautions for diclofenac as for selective COX-2 inhibitors'
    European Medicines Agency (EMA) 14th June 2013
    Available at:
    Last accessed: July 11, 2013

    MHRA Drug Safety Update June 2013
    Available at:
    Last accessed: July 11, 2013

    NICE - Evidence Services
    Available at:
    Last accessed: 06 November 2019.

    The drug database for acute porphyria (NAPOS)
    Available at:
    Diclofenac Last revised: June 30, 2010
    Last accessed: July 11, 2013

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Diclofenac Last revised: March 1, 2012
    Last accessed: July 11,2013

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