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Dantrolene parenteral

Updated 2 Feb 2023 | Malignant hyperthermia


Injection containing dantrolene sodium.

Drugs List

  • DANTRIUM INTRAVENOUS 20mg powder for solution for injection
  • dantrolene 20mg powder for solution for injection
  • Therapeutic Indications


    Malignant hyperthermia



    2.5mg/kg body weight by rapid intravenous injection. As long as the main clinical symptoms of tachycardia, hypoventilation, sustained hyperacidity (pH and pCO2 monitoring required) and hyperthermia persist, bolus injection should be repeated. Usually, a total dose of 10mg/kg body weight per 24hr is sufficient. This dose (10mg/kg) may need to be exceeded in individual cases. Safe uses up to 40mg/kg have been described. Based on this experience, higher dosages can be administered in isolated cases if required.


    Children aged 1 month to 18 years
    (See Dosage; Adult)

    Additional Dosage Information

    When mannitol is used for prevention or treatment of renal complication of malignant hyperthermia, the 3g of mannitol present as an excipient in each 20mg vial of intravenous dantrolene sodium should be taken into consideration when calculating total mannitol dose to be administered.


    For rapid intravenous injection.


    None known

    Precautions and Warnings


    Advise patient ability to drive or operate machinery may be impaired
    Contains mannitol
    If extravasation occurs follow local policy & seek expert help immediately
    Monitor blood oxygen concentration
    Monitor for development of acidosis
    Monitor serum electrolytes
    Monitor urine output

    All anaesthetic agents should be discontinued as soon as malignant hyperthermia is recognised.

    Dantrolen therapy can cause liver damage depending on the dosage and duration of the therapy and in some cases may result in a death of the patient.

    Due to the high pH of the intravenous formulation of dantrolene intravenous and potential for tissue necrosis, care must be taken to prevent extravasation of the intravenous solution into the surrounding tissue.

    Hyperkalaemia and myocardial depression have also been reported rarely in malignant hyperthermia-susceptible patients receiving intravenous dantrolene sodium and concomitant calcium channel blockers. It is recommended that the combination of intravenous dantrolene sodium and calcium channel blockers, such as verapamil, is not used during the reversal of a malignant hyperthermia crisis until the relevance of these findings to humans is established.

    There is a risk of undissolved crystals appearing in reconstituted solution, and a subsequent risk of exacerbation of injection site reactions or tissue necrosis. Manufacturer recommends the use of a filtration device when preparing the solution, see product literature for details.

    Pregnancy and Lactation


    Use dantrolene with caution during pregnancy.

    At the time of writing there is limited published information concerning the use of dantrolene during pregnancy and the safety of dantrolene in pregnant women has not been established. Dantrolene crosses the placenta. In a limited number of pregnancies where dantrolene was used shortly before delivery no foetal or newborn adverse effects have been observed, however there is no published experience concerning the use of dantrolene during the first and second trimesters (Briggs, 2011). The manufacturer recommends that dantrolene should only be used intravenously when the potential benefits have been weighed against the possible risk to mother and child. Schaefer (2007) states that use of myotonolytics such as dantrolene should be reserved for very special indications (e.g. malignant hyperthermia), However, exposure to dantrolene does not require either a termination of the pregnancy or invasive diagnostic procedures.

    Dantrolene is embryocidal in animals and, in some species, produced minor skeletal variations at the highest dose tested (Briggs, 2011).


    Use dantrolene with caution during breastfeeding.

    At the time of writing there is limited published information regarding the use of dantrolene during breastfeeding. Dantrolene has been detected in human milk at low concentrations (50 micrograms to 1.2 mg per litre) during repeat intravenous administration over 3 days. Hale (2014) states that no paediatric concerns have been reported but caution is urged. As limited information is available concerning the long-term use of dantrolene during breastfeeding, an alternate drug may be preferred. After short-term use, the drug would be expected to be eliminated from milk in 1 to 2 days. As the half life of dantrolene in milk is 9.02 hours, it is advisable to restart breastfeeding 60 hours after last dose. The infant should be observed for drowsiness, weakness, vomiting, diarrhoea and liver toxicity (which are known side effects of therapeutic doses in adults).

    Side Effects

    Abdominal cramps
    Abdominal pain
    Allergic reaction
    Cardiac failure
    Gastrointestinal bleeding
    Hepatic impairment
    Injection site reactions
    Muscle weakness
    Muscular fatigue
    Pleural effusion
    Pulmonary oedema
    Respiratory depression
    Respiratory failure
    Speech disturbances
    Uterine hypotonia


    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: June 2016

    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.

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

    Summary of Product Characteristics: Dantrium IV 20 mg powder for solution for injection. Norgine Limited. Revised November 2022.

    NICE Evidence Services Available at: Last accessed: 02 August 2017.

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Dantrolene. Last revised: 7 September 2013.
    Last accessed: 3 June 2016.

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