Skeletal Muscle Relaxants

Question 1

Baclofen

Answer 1

Class: skeletal muscle relaxant. spasmolytic drug
Apps: treat spasticity, improve mobility in pt. with MS and other spinal cord lesions
Mech: central acting relaxant, agonist for GABA B receptors (linked to K+ channels) = hypopolarizes neurons
Effects: drowsiness, nausea, constipation, weakness. withdrawal= increased spasticity, hallucinations, seizures

Question 2

Carisoprodol (Soma)

Answer 2

Class: Skeletal muscle relaxant
Apps: less used today b/c of newer agents. agonist effects on GABA A receptor in CNS
Mech: central acting, no direct effect on skeletal muscle
Effects: drowsiness, dizziness

Question 3

Cyclobenzaprine

Answer 3

Class: Skeletal muscle relaxant
Apps: relieve muscle spasm from acute, painful MSK conditions. Ineffective for cerebral palsy or spinal cord injury.
Mech: central action, no direct action on neuromuscular junction.
Effects: CNS depression, anticholinergic effects (drowsiness, xerostomia, dizziness)

Question 4

Tizanidine

Answer 4

Class: central acting, selective alpha2-adrenergic agonist
Apps: skeletal muscle relaxant to treat spasms, cramping, tightness due to MS, back pain, or injuries to spine
Mech: acts at presynaptic receptors to decrease excitatory amino acids which inhibits spinal motor neurons. Related to clonidine, but only 2% of its antihypertensive potency..
Effects: asthesia (weakness, fatigue, tiredness), zerostomia, increased spasm. Dose related hypotension.