LESSON 10: Neuromuscular Blocking Drugs Flashcards
Drugs that completely paralyze skeletal muscles (from normal tone to zero) by interfering with acetylcholine at neuromuscular junction
NEUROMUSCULAR BLOCKERS
Drugs that used to relieve skeletal muscle spasm & bring them from hypertonic state to normal muscle tone. (Ex. Dantrolene)
SPASMOLYTICS
These drugs interfere with transmission at the neuromuscular end plate and lack central nervous system activity
NEUROMUSCULAR BLOCKING DRUG
All of the available neuromuscular blocking drugs bear a structural resemblance to _________________.
acetylcholine
All of the neuromuscular blocking drugs are ___________________ and inactive orally and must be administered parenterally.
highly
polar (water soluble)
Non-competitive, agonist;
Act on the acetylcholine receptor (agonist drug)
DEPOLARIZING
Competitive, antagonist;
Attacks/goes against the acetylcholine receptor;
NON-DEPOLARIZING
NON-DEPOLARIZING EXAMPLE
Tubocurarine
DEPOLARIZING EXAMPLE
Succinylcholine (Anectine)
Decamethonium bromide (Syncurine®)
Ultra Short-Acting
Succinylcholine
Short-Acting
Mivacurium
Intermediate Acting
Vecuronium
● Atracurium
● Rocuronium
● Cis-atracurium
Long-Acting
Pancuronium
Resembles two acetylcholine molecules linked end to end, it has two quaternary ammonium cations which interact with the anionic sites on the muscle end plate receptors.
DEPOLARIZING
used to produce complete muscle relaxation for various surgical procedures
succinylcholine (anectine)
used as a
muscle relaxant for relatively short surgical procedures
Decamethonium bromide (Syncurine®)
another name for Decamethonium bromide (Syncurine®)
Suxamethonium
SUCCINYLCHOLINE: MAJOR SIDE EFFECTS
Hyperkalemia
Arrhythmia
Myalgia
Increased intraocular pressure
Increased intracranial pressu re (ICP)
Skeletal muscle contractions
Myoglobinuria
Increased intragastric pressure
succinylcholine side effects may be reduced by prior administration of non-paralyzing doses of____________________________
non-depolarizing neuromuscular-blocking agents.
These agents also contain a “double-acetylcholine” form; however this form is hidden by ring systems
NON-DEPOLARIZING
Contains 1-2 quaternary nitrogens which result in limited lipid-solubility
NON-DEPOLARIZING
pancuronium brand name
Pavulon®
NON-DEPOLARIZING drugs combine with________________ and
prevent binding of acetylcholine so prevent depolarization of the muscle cell membrane so inhibiting _______________.
nicotinic receptors; muscle contraction
NON-DEPOLARIZING drugs competitively block the receptors; this means that you can overcome their action by ____________ (increasing/decreasing) Ach concentration by giving Ach esterase inhibitors such as ____________________
increasing; pyridostigmine or neostigmine.
2 MAJOR CLASSES OF NON-DEPOLARIZING BLOCKERS
Isoquinoline derivatives, Steroid derivatives
Isoquinoline derivatives
● Tubocurarine
● Atracurium (Tracrium) ● Doxacurium(Nuromax) ● Mivacurium(Mivacron)
Steroid derivatives
● Pancuronium (Pavulon) ● Vecuronium (Norcuron) ● Pipecuronium (Arduan) ● Rocuronium (Zemuron)
Motor weakness, followed by skeletal muscle
flaccidity inexcitability to electrical stimulation
NON-DEPOLARIZING
Muscle fasciculations (very evident) especially over the chest and abdomen followed by complete paralysis
DEPOLARIZING
Order of Muscle Movement for NON-DEPOLARIZING
● 1 - smaller muscles (eg. facial, foot, hand)
● 2 - larger muscles
(eg. abdominal, trunk)
● 3 - diaphragm
Order of Muscle Movement for DEPOLARIZING
● 1 - arm, neck, and leg muscles
● 2- facial and pharyngeal muscles
● 3 - muscle follows
respiratory weakness rapidly, usually within 60
seconds
Recovery for NON-DEPOLARIZING
In reverse order, with the diaphragm regaining function first
Recovery for DEPOLARIZING
In reverse order
CONSIDERATION FOR CHOOSING A MUSCLE RELAXANT
Duration of action required
Route of excretion
endency to release histamine
Cardiopulmonary side effects
The ability to reverse the blockage
Contraindication to any specific muscle relaxant.
Cost
