Spasmolytic Drugs Flashcards
Indications:
heightened skeletal muscle tone due to:
release from inhibitory supraspinal control
increased activity of facilitory pathways
increased excitability of a and g motor systems
Spasmolytic Drugs
reduce1a afferent-mediated stretch reflex
enhance activity of inhibitory internuncial neurons
Goal of spasmolytic therapy
GABAB receptor agonist
Baclofen
Physiological Effect
Reduces calcium influx at 1a afferent nerve terminal
Reduces Substance P release in SC
Baclofen
Indication
Spinal Cord spasticity
Multiple Sclerosis
Toxicity
Drowsiness
Mental Disturbances (altered mental state)
Baclofen
Baclofen can be given orally or through
an intrathecal catheter to reduce side effects
Baclofen
Physiological Effect
Positive allosteric modulation of GABAA receptor
Opens Cl- channel, hyperpolarizes membrane
Indications
Flexor and extensor spasm
Spinal spasticity
MS
Diazepam
Toxicity
Drowsiness
Sedation
Contraindications
Acute narrow-angle glaucoma
untreated open-angle glaucoma
Diazepam
Physiological effect:
a2-adrenergic agonist mediated pre and post-synaptic
inhibition in spinal cord
Tizanidine
Much better tolerated- less drowsiness
Indications
Multiple sclerosis Spinal spasticity
Toxicity
Drowsiness Hypotension
Tizanidine
Physiological Actions
Blocks calcium release from SR of skeletal muscle
Dantrolene
Indications
Spasticity due to stroke, spinal cord injury,
multiple sclerosis or cerebral palsy
Malignant hyperthermia
Toxicity
Muscle weakness
Sedation
Hepatitis
Dantrolene
