Hyperexcitable muscle disorders, antispasm and antispastic medications - Study guide

Question 1

Order of process of muscle contraction

Answer 1

1. entry of Na+ = intiate action potential thru sarcolemma and T-tubules
2. activate voltage-sensitive receptors = trigger Ca2+ release into cytosol
3. Ca ions bind to troponin -> changes shape -> removes block of tropomyosin -> active sites exposed
4. contraction by myosin heads attaching and detaching with release of energy
5. Removal of Ca2+ by active transport into the SR
6. blocking respored and fibers relax

Question 2

What is the difference between upper motor neuron and lower motor neuron lesion?

Answer 2

Question 3

What is spasticity?

Answer 3

Velocity dependent increase in muscle tone
- because of increased excitability of the muscle stretch reflex

Question 4

What is a muscle spasm?

Answer 4

Involuntary muscle contraction

Question 5

What are the common neurologic disorders associated with spasticity?

Answer 5

MS
Stroke
Cerebral palsy
spinal cord and brain injuries
Neurodegenerative diseases affecting the:
- uppermotor neuron
- pyramidal
- extrapyramidal pathways

Question 6

What are the sx of severe spasticity?

Answer 6

• muscle stiffness
• muscle spasm
• rapid muscle contraction (clonus)
• fixed joints (contractions)
• exaggerated muscle jerks
• pain or tightness around the joint

Question 7

What are the primary goals of skeletal muscle relaxants?

Answer 7

• selective decrease in skeletal muscle excitability
• decrease pain w/o causing a profound decrease in muscle function

Question 8

What are the agents used for skeletal muscle relaxants?

Answer 8

anti-spasticity or antispasmodic

Question 9

What is brand name of baclofen?

Answer 9

Lioresal

Question 10

What is the brand name of chlorzoxazone?

Answer 10

Parafon forte

Question 11

What is the brand name of cyclobenzaprine?

Answer 11

Flexeril

Question 12

What is the brand name for Dantrolene?

Answer 12

dantrium

Question 13

What is the brand name of diazepam?

Answer 13

valium

Question 14

What is the brand name of tizanidine?

Answer 14

zanaflex

Question 15

What is the brand name of metaxalone?

Answer 15

Skelaxin

Question 16

What is the mechanism of action for baclofen?

Answer 16

Acts on the GABA which facilitates spinal inhibition of motor neuron = inhibits reflexes and decrease spasticity

Question 17

What are the uses for baclofen?

Answer 17

• treat spasticity with SC lesions
• for MS
• doesn’t cause as much generalized muscle weakness

Question 18

What are the adverse effects of baclofen?

Answer 18

• transient drowsiness (goes away in a few days)
• confusion and hallucinations with CVA or elderly
• nausea
• mm weakness
• headaches

Question 19

What is the route of administration of baclofen?

Answer 19

Oral
Intrathecal

Question 20

What is the mechanism of action for cyclobenzaprine?

Answer 20

poorly understood inhibition of muscle stretch reflex in the spinal cord

Question 21

What are the adverse of effects of cyclobenzaprine?

Answer 21

blurred vision
dizziness
drowsiness
lightheadness
dryness of the mouth

Question 22

What is the uses for cyclobenzaprine?

Answer 22

relief of muscle spasms

Question 23

What is the route of administation for cyclobenzaprine?

Answer 23

oral route is the usual way but can also be intravenous

Question 24

What is the mechanism of action for tizanidine?

Answer 24

• stimulates alpha-2 receptors in the spinal interneurons
• cause interneuron inhibition = decrease excitatory input into the alpha motor neuron
• decreases excitatability by both pre and post synaptic inhibition

Question 25

What are the uses for tizanidine?

Answer 25

- control spasticity from spinal lesions and central lesions - as effective as others - milder side effects and less generalized mm weakness - doesn't cause as much hypotension and other CV side effects compared to clonidine

Question 26

What are the adverse effects of tizanidine?

Answer 26

sedation dizziness dry mouth Less generalized weakness than baclofen or diazepam

Question 27

What is the route of administration for tizanidine?

Answer 27

oral or can also be intraveous

Question 28

What is the mechanism of action for diazepam?

Answer 28

facilitate GABAergic transmission in the CNS increases GABA-mediated inhibition of alpha motor neuron -> less excitability -> muscle relaxation

Question 29

What are the uses of diazepam?

Answer 29

Extensively in treating spasms associated with musculoskeletal injuries

Question 30

What are the adverse effects of diazepam?

Answer 30

- sedation and general reduction in psychomotor ability - long term use also limited by tolerance and dependence - sudden use withdrawl = seizues, anxiety, agitation, tachycardia and even death - overdose of diazepam = coma or death

Question 31

What is the mechanism of dantrolene?

Answer 31

stops the release of Ca from skeletal muscle into the SR

Question 32

What are the uses of dantrolene?

Answer 32

Treating severe spasticity not presribed to treat mm spasms caused by musculoskeletal injury ## Footnote Used in traumatic cord lesions, advanced MS, cerebral palsay, CVA

Question 33

What are the adverse effects of dantrolene?

Answer 33

- generalized muscle weakness is the most common - severe hepatoxicity - fatal hepatitis

Question 34

How is dantrolene use be counterproductive?

Answer 34

increased motor function with a decreased spasticity is offset by generalized mm weakness

Question 35

What are the uses for metaxalone?

Answer 35

mod to strong muscle relaxant used in symptomatic treatment of musculoskeletal pain

Question 36

What is the mechanism of action of metaxalone?

Answer 36

Has not yet been established but is possibly due to general CNS depression

Question 37

What are the adverse effects of metaxalone?

Answer 37

drowsiness irritability upset stomach ## Footnote There's a crap load but these are the most common (???)

Question 38

What is the route of administration for metaxalone?

Answer 38

oral route taken 3-4x per day

Question 39

What is the use of chlorzoxazone?

Answer 39

relax certain muscles in the body to get relief caused by acute musculoskeletal disfunctions

Question 40

What is the mechanism of action for chlorzoxazone?

Answer 40

MOA is unknown but might act @ the spinal cord and subcortical levels of the brain - this slows multisynaptic reflex arcs that has to do with muscle spasms

Question 41

What are some adverse effects of chlorzoxazone?

Answer 41

Drowsiness, dizziness, lightheadedness, tiredness, upset stomach, or headache may occur

Question 42

What is the route of administration for chlorzaxazone?

Answer 42

Oral route

Question 43

What is a patient controlled analgesia?

Answer 43

safe way for people to give themselves intravenous and pain medicine when they need

Question 44

What are the benefits of PCA?

Answer 44

- allows for better pain control with less side effects - but does need patient awareness and cognitive ability - increases patient satisfaction

Question 45

What is nociceptive pain?

Answer 45

pain coming from actual or threatened damage to non-neural tissue = activation of nociceptors

Question 46

What is neuropathic pain?

Answer 46

pain from neurons or somatosensory nervous system

Question 47

What is the difference between nociceptive vs neuropathic pain? | Picture

Answer 47

Question 48

What are the causes of acute pain?

Answer 48

generally known what caused the pain

Question 49

What are the causes of chronic pain?

Answer 49

often unknown

Question 50

What is the duration of pain for acute pain?

Answer 50

short well-characterized

Question 51

What is the duration of pain for chronic?

Answer 51

Persistent after healing greater than 3 months

Question 52

What is the treatment approach of acute pain?

Answer 52

When the cause is fixed = pain goes away - usually self limiting

Question 53

What is the treatment approach of chronic pain?

Answer 53

the underlying cause and pain disorder - pain control is the goal and not cure