Neuro Muscular Blockers Spasmolytics
DRUGS MOA INDICATIONS SIDE EFFECTS
Binds to nicotinic
Succinylcholine
Depolarizing
acetylcholine receptors at the
mimic ACH
increased salivation, bradycardia and
Succinylcholine neuromuscular junction,
hypotension
causing depolarization and
muscle contraction
M: Hoffman degradation and
d-tubocurarine hepatic Hypotension, bronchospasm
competitively antagonize ACh at the postsynaptic nicotinic receptor,prevent EPP ,AP is inhibited, thus muscle
E: renal mainly
Prolonged NMJ blockade,
Mivacurium M: plasma cholinesterases
Isoquinoline derivatives
Hypotension, bronchospasm
M: spontaneous (Hoffman)
Neuromuscular Blocking Drugs
degradation at body temp.
and pH
Drug of choice in liver failure
Atracurium E: renal mainly Induction of general anesthesia, Hypotension, bronchospasm
DI: incompatible with facilitation of endotracheal intubation,
Non Depolarizing
thiopental muscle relaxation during surgery
contraction
sodium (used in GA induction
phase)
M: liver Bronchospasm,
Vecuronium
E: bile mainly Anaphylaxis
Tachycardia, elevation in BP (Indirect
sympathomimetic effects i.e.
Steroid derivatives
M: liver (small amount)
Pancuronium autonomic nicotinic receptor
E: renally mainly unchanged
stimulation leading to NE release
(SNS)
M: liver
E: bile
Anaphylaxis (NOT HISTAMINE LIKE
Rocuronium DI: Phenytoin, carbamazepine
OTHERS)
may
cause recovery
GABA agonist, postsynaptic:
enhance GABA effect cause spasticity (spinal origin) multiple
hyperpolarization and muscle sclerosis, transverse myelitis, traumatic
Baclofen
relaxation, presynaptic: paraplegia, paraparesis, trigeminal
inhibit glutamate release neuralgia pain relief
drowsiness, dizziness, ataxia (lack of
GABAB receptor
voluntary coordination of muscle
movements)
muscle spasticity of any origin including
GABA A receptor, enhance
tetanus and reflex spasm of local origin
GABA effects hyperpol and
Diazepam Muscle relaxant of choice in the tx of
muscle relax, reduce muscle
spasticity of cerebral origin (i.e.
tone
cerebral palsy)
Centrally Acting
structurally similar to tricyclic
muscle spasm assoc. with acute, painful
CNS
antidepressants,
musculoskeletal conditions.
Spasmolytics
Cyclobenzaprine antidepressant activity, at may increase HR
Effective in muscle spasm of local origin
brain stem level, Reduces
rather than CNS origin
tonic somatic motor activity
General CNS depression,
CI: Depression or taking CNS
blocking spinal polysynaptic
adjuvant in painful musculoskeletal depressants, sedation, dizziness or
Methocarbamol reflexes, decreasing nerve
conditions lightheadedness, drowsiness,
transmission in spinal and
confusion
supraspinal pathways
blocks muscarinic
acetylcholine receptors,
inhibits central cholinergic pain assoc. with muscle spasm, tremor CI: myasthenia gravis. sedation, dry
Orphenadrine
receptor, inhibits the assoc. with parkinsonism mouth, dizziness
excitatory neurotransmitter
(glutamate) recepto
inhibit Ca2+ release by
Direct Acting
malignant hyperthermia, muscle
Muscle
blocking ryanodine receptor
Dantrolene spasticity caused by spinal cord injury, drowsiness, dizziness, fatigue
channels, suppress excitation
stroke, cerebral palsy, multiple sclerosis
contraction coupling
