B7.020 Drugs for Spasticity and Muscle Spasm

Question 1

spasticity

Answer 1

violent, painful, involuntary muscle contractions resulting from dysfunction of descending motor input

Question 2

causes of spasticity

Answer 2

trauma
inflammation
diseases like MS and cerebral pasy

Question 3

site of action of diazepam

Answer 3

spinal and supraspinal

Question 4

mechanism of diazepam

Answer 4

enhances GABAergic transmission at GABAa receptors

Question 5

principal uses of diazepam

Answer 5

all types of spasticity associated with spinal cord lesions

cerebral palsy

Question 6

side effects of diazepam

Answer 6

sedation and ataxia

Question 7

pharmacokinetics of diazepam

Answer 7

oral or IM administration

duration of action > 24 hrs due to active metabolites

Question 8

baclofen site of actions

Answer 8

spinal cord

Question 9

mechanism of baclofen

Answer 9

GABAb agonist
inhibits release of excitatory transmitters and increases threshold for excitation thus decreasing mono- and polysynaptic spinal reflexes

Question 10

principal uses of baclofen

Answer 10

spinal cord injuries

MS

Question 11

side effects of baclofen

Answer 11

drowsiness
insomnia
waskness
dizziness
ataxia
confusion
-can be decreased with intrathecal administration

Question 12

pharmacokinetics of baclofen

Answer 12

oral or intrathecal admin
rapidly absorbed after oral
t1/2 = 3-4 hours
excreted unchanged in urine

Question 13

site of action of tizanidine

Answer 13

spinal cord

Question 14

mechanism of tizanidine

Answer 14

a2 adrenergic agonist
reinforces pre-and post synaptic inhibition in the spinal cord
inhibits nociception

Question 15

principal uses of tizanidine

Answer 15

times when relief of spasticity is most important

due to short duration of action

Question 16

side effects of tizanidine

Answer 16

drowsiness
dry mouth
asthenia
hypotension
hepatotoxicity
visual hallucination

Question 17

tizanidine pharmacokinetics

Answer 17

oral administration
duration 3-6 hrs
metabolized by CYP1A2 (concomitant use with CYP1A2 inhibitors contraindicated)

Question 18

dantrolene site of action

Answer 18

muscle

Question 19

mechanism of dantrolene

Answer 19

reduces muscle contraction by decreasing Ca2+ release from the sarcoplasmic reticulum

Question 20

principle uses of dantrolene

Answer 20

paralysis and hemiparalysis
cerebral palsy
MS

Question 21

side effects of dantrolene

Answer 21

generalized muscle weakness

hepatotoxicity

Question 22

dantrolene pharmacokinetics

Answer 22

oral
t1/2 = 9 hr
hepatic metabolism
excreted in urine

Question 23

other uses of dantrolene

Answer 23

malignant hyperthermia

Question 24

site of action of botulinum toxin

Answer 24

muscle

Question 25

mechanism of botulinum toxin

Answer 25

inhibit ACh release from vesicles by binding to high affinity sites on cholinergic nerve terminals, translocating to the cytoplasm, and cleaving SNAP-25 or synaptobrevin-2

Question 26

botulinum toxin pharmacokinetics

Answer 26

injected into muscles
effects last for weeks - several months
can spread from site of injection and cause systemic effects

Question 27

side effects of botulinum toxin

Answer 27

pain at injection site
antibody formation
anaphylaxis

Question 28

muscle spasm drugs

Answer 28

used for treatment of acute muscle spasm caused by trauma or strain
NOT spasticity
cyclobenzaprine
carisoprodol

Question 29

mechanisms of muscle spasm drugs

Answer 29

acts as a sedative and/or at the level of the brainstem or spinal cord

Question 30

cyclobenzaprine

Answer 30

anticholinergic side effects include sedation, hallucinations
not effective for spasm due to palsy or spinal cord injury

Question 31

carisoprodol

Answer 31

metabolized into meprobamate, a barbiturate like sedative-hypnotic with abuse potential
side effects include sedation