1 - Skeletal Relaxants Flashcards
What are the two antispastic agents that are NOT centrally acting?
Dantrolene
Botulinum Toxin A
MOA for cyclobenzaprine (Flexeril)?
Cause a depressant effect of serotonergic neurons
Strong anticholinergic and antihistamine properties
Cyclobenzaprine (Flexeril) - clinical use?
Acute local muscle spasm
Cyclobenzaprine (Flexeril) is ineffective in treating muscle spasm due to:
Cerebral palsy or SCI
Cyclobenzaprine (Flexeril) can lower the ___ threshold, especially when combined with tramadol (Ultram)
Seizure
Clyclobenzaprine (Flexeril) - AE’s?
- Drowsiness
- Dry mouth
- Urinary retention
- Confusion (in elderly)
- SEROTONIN SYNDROME
Cyclobenzaprine (Flexeril) - CI’s?
- AMI
- MAOI’s
- ETOH
- Other CNS depressants
Cyclobenzaprine (Flexeril) - pregnancy?
No adverse events observed in animal studies
Orphenadrine (Norflex) - MOA?
Analog of BENADRYL
Antihistamine and anticholinergic properties
Euphoric and analgesic effects (unknown mechanism)
Orphenadrine (Norflex) - clinical use:
Tx of muscle spasm associated with acute painful musculoskeletal conditions
Orphenadrine (Norflex) - AE’s?
Anticholinergic effects (dry mouth, urinary retention, n/v, tachycardia)
Confusion (elderly)
Orphenadrine (Norflex) - CI’s?
Glaucoma, pyloric or duodenal obstruction, peptic ulcers, MG, BPH
Carisoprodol (Soma) C-IV - MOA?
Blocks interneuronal activity and depresses neuron transmission
Anxiolytic and sedative effects
Carisoprodol (Soma) - clinical use?
Relief of discomfort associated with acute, painful musculoskeletal conditions in adults
Short term use (2 to 3 weeks)
Carisoprodol (Soma) C-IV - AE’s?
Withdrawal symptoms can occur
Sedation, dizziness, HA, seizures
Confusion (elderly)
Carisoprodol (Soma) C-IV - pregnancy?
Adverse events have been observed in animal reproductive studies
Metaxalone (Skelaxin) - MOA?
Unknown - general depression of the nervous system
Metaxalone (Skelaxin) - Clinical use?
Relief of discomfort associated with acute, painful musculoskeletal conditions
Appears to cause less drowsiness than others
Metaxalone (Skelaxin) - AE’s?
Nausea, GI upset, sedation, HA, anxiety
Serotonin syndrome
Confusion (elderly)
Methocarbamol (Robaxin) - MOA?
Suppresses spinal polysynaptic reflexes
Methocarbamol (Robaxin) - Clinical use?
Adjunctive treatment of muscle spasm associated with acute painful musculoskeletal conditions
Treat muscle spasticity associated with tetanus poisoning
Methocarbamol (Robaxin) - AE’s?
Urine discoloration (black, brown, or green)
Drowsiness
Confusion (elderly)
Methocarbamol (Robaxin) - CI’s?
IV formulation in pt’s with renal impairment
Caution in hepatic impairment
Tizanidine (Zanaflex) - MOA?
Centrally acting alpha-2 agonist
Reduces spasticity by increasing presynaptic inhibition of motor neurons
Tizanidine (Zanaflex) - Clinical use?
Muscle spasticity
Short acting agent
Tizanidine (Zanaflex) - AE’s?
Drowsiness
Dry mouth, HOTN, hepatotoxicity
Dosage adjustment for renal or hepatic insufficiency
Baclofen (Lioresal) - MOA?
Orally active GABA-mimetic agent at the level of the spinal cord
Reduces Ca++ influx
Reduces excitatory transmitters
INHIBIT release of SUBSTANCE P
Baclofen (Lioresal) - clinical use?
Drug of choice for multiple sclerosis
As effective is diazepam and causes less sedation
Baclofen (Lioresal) - AE’s?
Drowsiness, nausea, confusion
Increased seizure activity in epileptic pt’s (must withdraw slowly)
Diazepam (Valium) C-IV - MOA?
Benzodiazepine
Enhancement of the inhibitory effects of GABA
Antispasmotic AND antispasticity
Diazepam (Valium) C-IV - clinical use?
Oral formulation used in cerebral palsy, MS, temporary muscle spasms, anxiety disorders, ETOH withdrawal
Diazepam (Valium) C-IV - AE’s?
Drowsiness, fatigue, ataxia
Dependency and tolerance
Diazepam (Valium) C-IV - pregnancy cat?
D
Gabapentin (Neurontin) - MOA?
Inhibition of voltage-dependent Ca++ channels
Analog of GABA
Gabapentin (Neurontin) - clinical use?
Generalized tonic-clonic seizures
Neuropathic pain and post herpetic neuralgia pain
Diabetic neuropathy (off-label)
Gabapentin (Neurontin) - AE’s?
Drowsiness, fatigue, dizziness, HA, wright gain
Dose adjustment for renal/hepatic insufficiency
Pregabalin (Lyrica) C-V - MOA?
Inhibition of voltage-dependent Ca++ channels
GABA derivative
Pregabalin (Lyrica) C-V - clinical use?
Partial onset seizure (adjunct)
Non-epileptic neuropathic pain associated with: diabetic neuropathy, fibromyalgia, restless leg syndrome, social phobia
Pregabalin (Lyrica) - AE’s?
Drowsiness fatigue GREATER THAN Gabapentin
Dizziness, weight gain, sexual dysfunction
Pregabalin (Lyrica) C-V - discontinuation symptoms?
Insomnia, nausea, HA, diarrhea
Dantrolene sodium (Rynodex) - MOA?
Reduces skeletal muscle strength by interfering with excitation-contraction coupling in the muscle fibers
Dantrolene sodium (Rynodex) - clinical use?
IV DOC for tx of malignant hyperthermia (MH)
Oral - spasticity d/t SCI, stroke, MS
Not indicated for spasms d/t rheumatic d/o’s
Dantrolene sodium (Rynodex) - AE’s?
Muscle weakness, sedation, hepatotoxicity
Non-cosmetic uses for botulinum toxin?
Chronic migraines (2nd line agent)
Cervical dystonia
Blepharospasm
BLUF on toxin A:
Slower onset
Longer duration of efficacy
Less pain of injection
BLUF on toxin B:
Faster onset
Shorter duration of efficacy
More painful injection site
Generally for cervical dystonia only
