✔️Dantrolene inhibits calcium release via RyR1 antagonism and impairs calcium-dependent muscle contraction.
✔️This rapidly halts the increases in metabolism and secondarily results in a return to normal levels of catecholamines and potassium.
✔️Dose is 2 mg/kg; repeat every 5 minutes until vital signs normalise , to a total dosage of 10 mg/kg if needed.
✔️dantrolene takes ~ 6 minutes to have any effect
✔️The solution is prepared by mixing 20 mg of dantrolene with 3 g of mannitol in 60 ml of sterile water.
✔️Since dantrolene is relatively insoluble, preparation is tedious and time consuming, and its preparation should not be the responsibility of the primary anesthesiologist involved in the patient’s management. (May occupy several nurses)
✔️All patients who develop MH, require at least 24 hours of posttreatment management in a critical-care setting as there is chance of reappearance of symptoms ( known as recrudescence )
🔸In the ICU, continue @1mg/kg q6h for 24 hours
🔸may be given enterally if GIT functioning (price ~ 1000 x less)
✔️the actions of dantrolene include:
🔸 release of Ca ++ from the SR, without affecting re-uptake
🔸 ? antagonises the effects of Ca ++ at the actin/myosin - troponin/tropomyosin level
🔸muscular weakness, which may potentiate NMJ blockade ~ 5-15 mg/kg produces significant muscular relaxation
🔸there is no effect on NMJ transmission
🔸up to 15 mg/kg there is no significant effect on the CVS
🔸up to 30 mg/kg there is no significant effect on respiration
#dantrolene , #MalignantHyperthermia, #mh ,#anaesthesia
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