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Transcript 
MCMP 407
Spasmolytics
• Chronic neurologic diseases
•Cerebral Palsy, Multiple Sclerosis
• Acute Injury
•Spinal cord damage, muscle inflamation
Goal of therapy: Reduce spasticity and pain, while
retaining function
MCMP 407
Spasmolytics
O
H3C
N
N
Cl
Diazepam
(Valium)
Benzodiazepines
(Diazepam, etc.)
 GABAA Receptors
 CNS and Spinal Cord
 Side Effects: Sedation
MCMP 407
Spasmolytics


H2N
CO2H



Cl


Baclofen
(Lioresal
GABAB receptor agonist
Activation of K+ channels
CNS and Spinal cord
(-)-Baclofen is the active
isomer
Less sedation than BZDs
Intrathecal pumps now used in
chronic conditions
Warning for severe withdrawal
syndrome from intrathecal use
 Altered mental status,
hyperpyrexia, exaggerated
spasticity, muscle rigidity, and
rhabdomyolysis
MCMP 407
Spasmolytics
N
S

N
H
N
Cl
Tizanidine
(Zanaflex)
N
N
H




a2 adrenergic receptor
agonist
Congener of clonidine
Presynaptic inhibition of
motor neurons
1/10-1/50th potency as
clonidine in lowering
blood pressure
Side Effects: Drowsiness,
hypotension, dry mouth
MCMP 407
Spasmolytics



CHCH2CH2N(CH3)2

Cyclobenzaprine
(Flexeril)

Tricyclic structure
May act at level of brain
stem
Strong antimuscarinic
effects (sedation)
Ineffective in the
treatment of chronic
neurological disorders
Use: Relief of acute
muscle spasm due to
injury or strain
MCMP 407
Atropine vs. Cyclobenzaprine
MCMP 407
Spasmolytics
Other drugs similar to Cyclobenzaprine
(Flexeril)
 Chlorzoxazone (Paraflex, Parafon)
 Orphenadrine (Norflex)
 Carisprodol (Soma)
MCMP 407
Spasmolytics
O
O
O2N
H
C
N
NN
Na +
O
Dantrolene Sodium
(Dantrium)



Interferes with excitationcontraction coupling
Reduces release of Ca++ from
the sarcoplasmic reticulum
Blocks contraction



Side Effects: Muscle weakness,
sedation, rare hepatitis
Uses: Cerebral palsy, multiple
sclerosis
Also Malignant Hyperthermia
MCMP 407
Neuromuscular Blockers
Motor neuron
ACHEsterase
Skeletal
Muscle
MCMP 407
Properties of neuromuscular blockers
Drug
Elimination via
Duration of action (minutes)
Short-acting
Succinylcholine
Mivacurium
Plasma AChE
Plasma AChE
5-10
10-20
Intermediate-acting
Atracurium
Spontaneous
Vecuronium
Hepatic and renal
Rocuronium
Hepatic and renal
20-35
20-35
20-35
Long-acting
Pancuronium
60
Renal
MCMP 407
Clinical use of neuromuscular blockers



Muscle relaxation during surgical procedures
Endotracheal intubation
Maintain controlled ventillation
MCMP 407
Clinical problems associated with
neuromuscular blockers




Potentiated by inhaled anesthetics (Isoflurane)
Potentiated by aminoglycosides and calcium
channel blockers
Can block autonomic ganglia at higher doses
Respiratory paralysis
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