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Dantrolene oral

Updated 2 Feb 2023 | Skeletal muscle relaxants


Oral formulations of dantrolene.

Drugs List

  • DANTRIUM 100mg capsules
  • DANTRIUM 25mg capsules
  • dantrolene 100mg capsules
  • dantrolene 25mg capsules
  • Therapeutic Indications


    Muscular spasticity



    Maintain each dose for 7 days to assess response before further dose adjustment.

    Week one: 25mg once a day.

    Week two: 25mg twice a day.

    Week three: 50mg twice a day.

    Week four: 50mg three times a day.

    Week five: 75mg three times a day.

    Week six: 75mg four times a day.

    Week seven: 100mg four times a day.

    Maximum dose should not exceed 400mg a day.
    If beneficial response is not observed after a total of 6 to 8 weeks, therapy should be withdrawn.


    Chronic severe spasticity of voluntary muscle (unlicensed)
    Children aged 12 to 18 years
    Initial dose: 25mg once a day.
    After 7 days increase the dose to 3 times a day.
    Every 7 days increase the dose by a further 500micrograms/kg, based on individual patient, until a satisfactory response.
    Maximum dose: 2mg/kg three to four times daily (maximum total daily dose 400mg).

    Children aged 5 to 12 years
    Initial dose: 500micrograms/kg once a day.
    After 7 days increase the dose to 500 micrograms/kg three times daily.
    Every 7 days increase the dose by a further 500micrograms/kg, based on individual patient, until a satisfactory response.
    Maximum dose: 2mg/kg three to four times daily (maximum total daily dose 400mg).


    Children under 5 years
    Hepatic impairment

    Precautions and Warnings

    Children aged 5 to 18 years
    Patients over 30 years
    Cardiovascular disorder
    Glucose-galactose malabsorption syndrome
    History of hepatic impairment
    Lactose intolerance
    Respiratory disease

    Pre-existing liver dysfunction may enhance risk of hepatotoxicity
    Advise ability to drive/operate machinery may be affected by side effects
    Only consider re-introduction after liver abnormalities if of major benefit
    Contains lactose
    Contains sunset yellow (E110) - may cause allergic reaction
    Perform liver function tests before commencing therapy and during therapy
    During long term use make clinical examinations at regular intervals
    Advise patient/carer to contact GP immediately if signs of liver disorder
    Discontinue if hepatitis develops
    Discontinue at first signs of jaundice
    Discontinue if liver function tests become abnormal
    Discontinue if no response to treatment after 6 to 8 weeks
    Discontinue if severe and persistent diarrhoea develops
    Advise patient to avoid alcohol during treatment

    Perform liver function tests before commencing therapy to establish baseline liver function and identify any pre-existing liver disease and then continue monitoring these tests during ongoing therapy.
    Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase and total bilirubin should be measured.

    Pregnancy and Lactation


    Dantrolene is contraindicated in pregnancy.

    Animal studies have proved satisfactory but manufacturer advises avoidance. There is no evidence of first or second trimester exposure to dantrolene sodium and a risk: benefit ratio in humans has not as of yet been established (Briggs, 2011).

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Dantrolene is contraindicated in breastfeeding.

    Animal studies have proved satisfactory but manufacturer advises avoidance. Dantrolene is secreted in human breast milk and there is no current information available on the long term use of dantrolene during breastfeeding and an alternative drug may be preferred. Relaxant effect of lower doses of the better studied diazepam should be used in short term cases (Schaefer, 2007)

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Abdominal pain
    Abnormal liver function tests
    Blood pressure changes
    Elevation of liver enzymes
    Idiosyncratic hepatic dysfunction
    Increased urinary frequency
    Intestinal obstruction
    Pleural effusion
    Respiratory depression
    Speech disturbances
    Urinary incontinence
    Urinary retention
    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: May 2015.

    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.

    Martindale: The Complete Drug Reference (online) London: Brayfield A (ed). Pharmaceutical Press Accessed on 07 May 2015.

    Medications and Mothers' Milk, Sixteenth Edition (2014) Hale, T and Rowe, H, Hale Publishing, Plano, Texas.

    Summary of Product Characteristics: Dantrium 25mg capsule. Norgine Ltd. Revised December 2016.
    Summary of Product Characteristics: Dantrium 100mg capsule. Norgine Ltd. Revised December 2016.

    NICE - Evidence Services
    Available at:
    Last accessed: 27 June 2017.

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