Magnesium: a versatile drug for anesthesiologists

From: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3726845/

MOA: multiple including blockade of nmda and Calcium channels 

Magnesium has multiple advantages including:

  • Reduced opioid reqs post op
  • Reduced Mac with tiva
  • Tiva reduced remi use -> reduced hyperanalgesia post op
  • Intrathecal MG prolongs labor analgesia, especially motor block and iv Mg prolongs muscle blockade when spinal wearing out 
  • Potentiates Nondepolarizing blockade,  can improve incubating conditions while reducing hemodynamic response to intubation 
  • Reduced post op shivering >70%

However caution:

  • Reduced inh Mac questionable 
  • Blunts release of NE / epi watch out in critically ill patients 
  • Cardiovascular depression possible when given as bolus 

Dosing: 

loading dose of 30-50 mcg/kg followed by a maintenance dose of 6-20 mcg/kg/h (continuous infusion) until the end of surgery; alternatively 4mg bolus