Skeletal Muscle Relaxants

Question 1

Spasmolytic Drugs: MOA

Answer 1

CNS - reduce abnormally elevated tone

Question 2

Chronic vs. Acute muscle spasms

Answer 2

Chronic:
A. CNS
-Baclofen
-Cyclobenzaprine*
-Diazepam
-Tizanidine

B. Muscle Action

• Dantrolene
• Botulinum toxin

Acute:
-Cyclobenzaprine*

Question 3

Baclofen

Answer 3

MOA: activates GABA

Uses: cerebral palsy, MS

Route: oral and Intrathecal (into spinal canal)

ADE: sedation, muscle weakness

Question 4

Cyclobenzaprine

Answer 4

MOA: inhibits spinal stretch reflex, antimuscarinic effects

Use: acute spasm due to muscle injury or inflammation

Route: oral

ADE: anti-muscarinic effects, sedation **use at bedtime!

Question 5

Carisprodol (Soma)

Answer 5

• IV

- taper slowly over 14 days*

Question 6

Diazepam

Answer 6

MOA: activates GABA, postsynaptic

Route: oral or IV

Pharmacokinetics: long duration (12-24 hours)

ADE: Idiosyncratic parodoxical effect hyperexcitable/combatitive state***

Question 7

Tizanidine

Answer 7

MOA: alpha 2 agonist

indications: MS, stroke, ALS

ADE: hypotension

Question 8

Dantrolene

Answer 8

MOA: reduces myosin-actin interaction

indications: malignant hyperthermia (IV)**

Question 9

Botulinum toxin

Answer 9

uses:
- cerebral palsy
- MS

duration: 2-3 months