non-depolarizing muscle relaxants
Terms in this set (50)
NDMR mechanism of action
competitive antagonism at the alpha-subunit of the post-junctional nAChR
how do volatile agents cause altered response to NMB?
-dose dependent enhancement in magnitude and duration of the NDMR
-can induce skeletal muscle relaxation at the level of the spinal cord via nAChR
how do ahminoglycosides affect NDMR?
can stimulate pre-synaptic receptors, causing a decrease of ACh release, prolonging the NDMR effects
how do local anesthetics affect NDMR?
-interfere with pre-junctional release of ACh
-directly depress skeletal muscle fibers
-esters compete for plasma cholinesterase
how does quinidine affect NDMR?
depresses pre-junctional release of ACh
how do diuretics affect NDMR?
furosemide depresses release of ACh
how does magnesium affect NDMR?
stabilizes post-junctional membranes
how do anti-convulsants cause altered responses of NDMR?
-increased hepatic clearance of NDMR
-increased protein-binding of NDMR
-increased enzyme induction
what is an example of an anti-convulsant that alters the responses of NDMR?
how do cyclosporines cause altered responses to NDMR?
depress the release of ACh
how does hypothermia cause an altered response to NDMR?
-slowed rate of effect site equilibrium
how do burn injuries >30% cause an altered response to NDMR?
alters the affinity of the receptor ACh
trade name for pancuronium
what type of NDMR is pancuronium?
60-80% renal, 10% biliary
how does pavulon effect the CV system?
stimulation via blocking mAChR, increasing the HR
commercial prep of pavulon:
2 mg/mL pancuronium bromide
IV 0.1-0.2 mg/kg
trade name for vecuronium
what type of NDMR is norcuron?
40% renal, 10-20% biliary
commercial prep of vecuronium:
10 mg lyophilized powder vecuronium bromide; must be diluted to 1 mg/mL
trade name for cisatracurium:
what type of NDMR is nimbex?
Hoffman elimination dependent on pH and temperature
renal clearance 10-30%
commercial prep of cisatracurium:
2 mg/mL cisatracurium besylate
trade name for rocuronium:
what type of NDMR is zemuron?
30-40% renal, 60% biliary
commercial prep of rocuronium:
10 mg/mL rocuronium bromide
0.6-1.3 mg/kg, max of 50 mg for induction
what causes up-regulation of ACh receptors?
loss of neuronal influences on muscle cells lead to up regulation of the receptors and spread them into peri- and extra-junctional areas
what results from up-regulation of AChR?
-new receptors are immature and have altered sensitivity and affinity
-agonists will depolarize the new AChRs more easily and lead to exaggerated cation fluxes
-increases requirements of NDMR
down-regulation of AChR:
-increase in sensitivity can also be seen
-lower doses of NDMR required
examples of conditions causing down-regulation of AChR:
-chronic cholinesterase inhibition
which muscle relaxants cause a release of histamine?
histamine is released from MAST cells: