Hyper excitable Muscle Disorders: Anti Spasm and Anti Spastic Medications

Question 1

what muscle cell filaments are necessary for muscle contraction?

Answer 1

actin and myosin

Question 2

Describe UMN lesion

Answer 2

*location: cerebral hemisphere, cerebellum, brainstem, spinal cord
*spasticity
*hyperreflexia
*cortical sensation loss
*no fasiculations

Question 3

describe LMN lesion

Answer 3

*anterior horn cell, nerve root, peripheral nerves, neuromuscular junction
*hypotonia
*fasciculations present
*hyporeflexia
*peripheral sensory loss
*abnormal nerve conduction

Question 4

Compare and contrast spasms vs spasticity

Answer 4

Spasticity: velocity dependent increase in muscle tone cause by the increased excitability of the muscle stretch reflex. UMN lesion, stiff, hypertonic, hyper reflexive, fixed joint, pain or tightness around joints
Spasm: Involuntary muscle contraction.
LMN injury, spinal stenosis, jerks, twitches, cramps

Question 5

List out key neurological disorders associated with spasticity

Answer 5

MS, CP, SCI, TBI, Motor neuron disease, post stroke

Question 6

list of key conditions associated with spasms

Answer 6

MSK pain, fibromyalgia, sciatica, mechanical LBP, herniated disk, spinal stenosis, myofascial pain

Question 7

What are skeletal muscle relaxants

Question 8

Drugs for spasticity

Answer 8

Botulinum toxin, Baclofen, Dantrolene, Diazepam, Tizanidine, Gabapentin

Question 9

Drugs for Spasms

Answer 9

Carisoprodols, Cyclobenzaprine,
Methocarbanol, Orphenadrine

Question 10

What is the MOA of the anti-spasticity drugs?

Answer 10

1.Baclofen: GABA-B receptor agonist in the spinal cord to inhibit reflexes and decrease spasticity. Oral or injection. BEST for MS.
2. Dantrolene: It acts directly on skeletal muscle, inhibiting calcium release and thus muscle
contraction (actin/ myosin)
3. Tizanidine: alpha 2 adrenergic receptor agonist that reduces spasticity by increasing pre and post synaptic
inhibition.
4. Botulinum toxin: Injection which inhibits acetylcholine release at the NMJ reducing
muscle contraction (flaccid paralysis)
5. Gabapentin: enhance GABA effect in the SC

Question 11

What is the MOA of spasmolytics?

Answer 11

1.Carisoprodol: Its exact mechanism is unknown, but it’s believed to alter interneuron activity in the spinal cord and descending reticular formation in the brain.
2. Cyclobenzaprine: Works centrally, likely by decreasing activity in the brainstem, to relieve muscle spasms.
3. Methocarbamol: Its mechanism isn’t fully understood, but it has central muscle relaxant
properties.
4. Orphenadrine: Anticholinergic properties are believed to be responsible for its muscle relaxant effects.

Question 12

What are the key differences in target, mechanism, and usage between anti-spasticity drugs and spasmolytics?

Answer 12

Anti-spasticity
*target: conditions with increased muscle tone due to CNS disorders
*mechanism: specific targets
*usage: chronic in nature
Spasmolytics
*target: peripheral conditions involving acute, painful muscle contractions
*mechanism: less clear and diverse
*usage: acute conditions

Question 13

Describe antispasm polysynaptic inhibitors MOA

Answer 13

MOA: Theorized to act on polysynaptic reflex arc in the spinal cord which could decrease AMN excitability and cause relaxation of skeletal muscle

Question 14

what are common anti-spasm polysynaptic inhibitors? what are the AEs?

Answer 14

Carisoprodol, Cyclobenzaprine, Methocarbamol, Orphenadrine Citrate
AEs: drowsy, dizzy, nausea, lightheaded, vertigo, ataxia, headache, tolerance, physical dependence

Question 15

What is the MOA of Diazepam? What are the 6 intrinsic effects of benzodiazepines like Diazepam?

Answer 15

Diazepam is a GABA-A receptor modulator that increases GABA-mediated inhibition of AMN which leads to less excitability which leads to muscle
relaxation
6 Intrinsic effects: Anxiolysis, anterograde
amnesia, sedation/hypnosis, anticonvulsant, antiemesis and muscle relaxation

Question 16

What are the adverse effects of Diazepam?

Answer 16

1. Sedation and a general reduction in psychomotor ability
2. Long-term use also limited by tolerance (increasingly higher doses required) and dependence
3. Sudden withdrawal after prolonged use can cause seizures, anxiety, agitation, tachycardia, and even death.
4. Overdose of diazepam can result in coma or death

Question 17

What is the drug used as an antidote for overdose of benzodiazepines like Diazepam?

Answer 17

Flumazenil

Question 18

What are the uses and adverse effects of Baclofen?

Answer 18

Uses: to treat spasticity associated with SC lesions, mainly MS.
AE: transient drowsiness, confusion or hallucinations in the elderly, nausea, weakness, headache

Question 19

What are the uses and adverse effects of alpha-2 agonists

Answer 19

Uses: control spasticity from SC lesions or central lesions. Generally have milder SE and less generalized weakness
AE: sedation, dizziness, dry mouth, less generalized weakness than oral baclofen or diazepam

Question 20

What are the uses and adverse effects of Gabapentin?

Answer 20

Uses: decrease spasticity associated with SCI and MS, often used in combination with other anti-spasticity agents
AE: sedation, fatigue, dizziness, ataxia

Question 21

What are the uses and adverse effects of Dantrolene?

Answer 21

Uses: effective in treating severe spasticity from SCI, MS, CP, CVA
AE: generalized muscle weakness, severe hepatotoxicity and fetal hapatitis