1 Muscle Relaxants Flashcards
What is spasticity characterized?
characterized by an exaggerated muscle stretch reflex. Seen in injuries to CNS and brain.
NEURO
What are spasms?
increased tension in a specific muscle that is a continuous tonic contraction, that is usually due to a orthopedic injury.
ORTHO
Skeletal muscle relaxants are used to treat conditions associated with …
hyperexcitable skeletal muscle –
spasticity and muscle spasms
What are the top 2 agents used to treat muscle spasms?
Diazepam (Valium) and
benzodiazepines
What mechanism do skeletal muscle relaxants use to treat muscle spasms?
Work by increasing the central inhibitory effects of GABA
– Diazepam has an inhibitory effect on
alpha motor neuron activity in the spinal cord
What is the oldest medication for treating muscle spasm and tetanus (tremors)?
Valium/ diazepam
What are the side effects of skeletal muscle relaxants? What if you suddenly stop taking them?
– Sedation
– Reduction in psychomotor ability
– Tolerance
– Physical dependence
– Sudden withdrawal can cause seizures, anxiety, agitation, tachycardia and death
What are the uses of baclofen as a skeletal muscle relaxant?
administered orally for spasticity associated with SC lesions, including traumatic injuries resulting in paraplegia or quadriplegia and MS
Administered systemically for MS
The best way is intrathecal baclofen
What are the side effects of baclofen?
Drowiness
Seizures
Confusion
fatigue
Administered systemically, baclofen is _____ effective in treating spasticity because patients are ______ prone to adverse side effects, and because baclofen ________ cross the blood-brain barrier
baclofen is less effective
patients are more prone to adverse side effects
baclofen does not cross the blood-brain barrier
In addition to being a skeletal muscle relaxant, what is another use for baclofen?
Oral baclofen is also used to reduce alcohol consumption in people with chronic alcoholism.
Low doses of baclofen can reduce the craving and desire for alcohol.
Blocks alcohol binding
What is the best way to administer baclofen?
Intrathecally
The pump is implanted subcutaneously in the abdominal wall.
This allows increased drug effectiveness with smaller drug doses, with fewer systemic side effects because of decreased drug circulating bloodstream
What are the uses for intrathecal baclofen as a skeletal muscle relaxant?
– Severe spasticity
– reduce pain of central origin
– Reduce chronic pain
– Functional improvement in motor control
What are the adverse effects of intrathecal baclofen?
– Pump malfunction
– Over dose; respiratory depression, ↓ cardiac
function, and coma
– Tolerance
– Withdrawal syndrome; fever, confusion, delirium, seizure
Sidebar: infection from implanting pump
When would you use diazepam/ valium as a skeletal muscle relaxant? What are the side effects?
Reduces spasticity and muscle spasms
Uses: spasticity from cord lesions & CP
Side effects: sedative, tolerance
