Pharm L18, T2 NMJ blockers.txt

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Pharm L18, T2 NMJ blockers.txt
2011-10-11 19:13:47
Pharm L18 T2 NMJ blockers

Pharm L18,T2 NMJ blockers
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  1. three common endings for NMJ blocker drugs?
    • -curonium
    • -curium
    • -curarine
  2. What type of receptors are found at the NMJ of skeletal muscle?
  3. Function fo succinylcholine at NMJ?
    • **depolarizing blocker
    • Starts off by depolarizing but eventually haults any repolarization and causes desensitization
  4. What moves in and out of Ach receptors at the motor end plate?
    • Na in
    • K out
  5. T/F using an AchE inhibitor will slow down APs?
    F, they will speed up b/c the mini potentials will enter summation faster due to non-inhibition of Ach on nicotinic receptors
  6. Highlight drug for NMJ depolarizing blockers?
  7. What happens to non-depolarizing blocks in the presence of anesthetics?
    potentiation of block
  8. T/F non-depolarizing NMJ blocks are competitive
    T, therefore can be reversed w/ AchE inhibitors or excessive Ach release
  9. What is the duration time of non-depolarizing drugs when metabolized through the kidney and liver?
    • kidney: long
    • Liver: short
  10. Tubocurarine, pancuronium, doxacurium duration
    Long 2-3 hrs
  11. Vecuronium, atracurium, cisatracurium duration & onset?
    Intermediate 30-90 min, 2-4 min onset
  12. Rocuronium duration & onset
    intermediate, 1-2 min onset
  13. Non-depolarizing drug muscle paralysis order?
    • small mm first (hand, eye, etc...)
    • large mm (trunk)
    • respiration mm
    • ** recovers in opposite direction
  14. Compare train-of-four & Posttetanic potentiation of NDep. block and Dep. block?
    • Fade
    • NDep: fades
    • Dep: constant
    • Posttetanic potentiation (overshoot b.c of Ach buildup)
    • NDep: present
    • Dep: absent
  15. What are the two complications that have removed Tubocurarine from common use?
    • Histamine release
    • Ganglion blockade in heart
  16. Succinylcholine onset & duration?
    • Onset: 1 min
    • duration: 5-10 min = great drug for short procedures
  17. What metabolizes succinylcholine?
    Pseudocholinesterase in plasma
  18. What test is used to measure cholinesterase effect on succinylcholine? Normal rate?
    • Dibucaine number
    • 80% = normal
  19. T/F AchE inhibitors can reverse effects of Succinylcholine?
    F, b/c succinylcholine is not a competitive antagonist of nicotinic receptors at the NMJ
  20. describe the Phase I blockade of succinylcholine?
    Continued depolarization until end plate no longer responds = flaccid paralysis
  21. Describe Phase II block w/ succinylcholine
    membrane repolarizes but receptor is desensitized to Ach = appears similar to non-depolarizing block
  22. Why is succinylcholine dangerous for denervation and burn pts?
    Hyperkalemia can be heightened b/c of depolarization of cells and excess K released
  23. M2 response to Succinylcholine
    slow heart
  24. N receptor response to succinylcholine
  25. cardiac issue it two doses of succinylcholine given together?
  26. Issue caused when S.choline and Halothane are mixed?
    Malignant hyperthermia
  27. muscular side effects of succinylcholine?
    • post-op pain
    • intragastric pressure
    • increased intraocular pressure
  28. Two drugs that block calcium channels and enhance NMJ blocks?
    • 1) Aminoglycosides: inhibit calcium channel
    • 2) Tetracyclines: chelate calcium
    • ** both stop release of Ach from presynaptic cleft = no stimulation
  29. What type of antagonist is a ganglion blocker?
    non-depolarizing competitive antagonist
  30. Problem with ganglion blockers?
    Block all autonomic ganglia ( inhibit a lot of PNS and SNS systems)
  31. NM and NN drugs used as Ganglion blockers?
    • NM= decamethonium
    • NN = hexamethonium
  32. Most common ganglion blocker?
  33. What is required in a muscle to be affected by ganglion blockers?
    high tone (eye, BVs, GI, etc...)
  34. Ganglion blockade effect on eye, blood vessels, heart, urinary, sweat, BP, GI?
    • eye: mydriasis bilaterally (cycloplegia), no tears
    • blood vessels: vasodilation, hypotension, BP down (recovered via baro receptor)
    • heart: contractility blocked, tachycardia (decreased vagal tone)
    • urinary: urinary retention, ejaculation reduced
    • sweat: gone = ward
    • BP: normal
    • GI: constipation, no hunger pain, no saliva, dry mouth