• 20mg dantrolene powder for solution for injection


  • Add 60mL sterile water for injection and shake until solution dissolved
  • Using the filter device provided, draw up the reconstituted solution into a syringe
  • Remove the filter device before attaching the syringe to an IV cannula or giving set

Compatibility / Stability

  • No further dilution permitted


Use a new filtration device with every vial of Dantrium IV. Administer Dantrium IV immediately upon filtration.

Bolus intravenous injection:

Management of malignant hyperthermia crisis, or neuroleptic malignant syndrome (unlicensed):

  • Administer an initial dose: 2.5 mg/kg body weight IV (9 vials for a 70 kg adult)
  • If there is no response after 5 minutes repeat a dose of 1 mg/kg
  • Further doses can be given every 5 minutes to a maximum of 10 mg/kg in 24 hours
  • The required dose to be given as a bolus intravenous injection
  • Bolus injections may be administered rapidly (over at least one minute)


  • Monitor BP, Resp. rate, pulse, Temp, pH, pCO2, K+


Dantrolene sodium has a high pH and may cause venous irritation and tissue damage in cases of extravasation. If a central venous access device is unavailable, administer via a large peripheral vein monitoring insertion site closely using a recognised phlebitis scoring tool. Re-site cannula at first signs of inflammation.

Additional Info.

  • For a 70kg patient, if a cumulative dose of 10mg/kg is needed this will amount to approximately 36 vials
  • Due to the potential for undissolved crystals/particles to appear in the re-constituted product and the subsequent potential risk of exacerbation of injection site reactions/tissue necrosis from crystals within affected vials, use of the filtration device when drawing up the solution is required at all times
  • Each vial of Dantrium IV contains 3g mannitol (for adjustment of isotonic solutions). This amount should be considered if mannitol is used to prevent and treat renal complications related to malignant hyperthermia
  • Caution should be exercised if hyperkalaemia symptoms occur (muscular paralysis, ECG changes, bradycardia arrhythmias) or in cases of pre-existing hyperkalaemia (renal insufficiency, digitalis intoxication etc.), as an increase in serum potassium has been demonstrated in animal trials as a result of dantrolene
  • Liver damage may occur during dantrolene therapy. This is dependent on the dosage and duration of therapy and may run a lethal course
  • In CUH: stock kept in ED Antidote press, Theatres, MH Theatre

Content by Miriam Flynn (Chief Pharmacist CUH). Last review Dr ÍOS 1/07/24.