Skeletal Muscle Relaxant Meds Flashcards
Which two antispastic agents are not centrally acting?
Dantrolene and Botulinum Toxin A
What are the 5 CNS Depressants for antispastics?
Cyclobenzaprine (flexeril) Carisoprodol (soma) Metaxalone (skelaxin) Methocarbamol (robaxin) Orphenadrine (norflex)
What is the 1 central a2 agonist for antispastics?
Tizanidine (zanaflex)
What are the 4 GABA agonists for antispastics?
Baclofen
Diazepam (Valium)
Gabapentin
Pregabalin
This antispastic is structurally related to TCAs, has a depressant effect on serotonergic neurons, strong anticholinergic/antihistamine properties, and is best used for acute local muscle spasms.
Cyclobenzaprine
Especially if used in combination with tramadol, this antispastic has the potential to lower the seizure threshold
Cyclobenzaprine
Two most common AEs of cyclobenzaprine?
Drowsiness and serotonin syndrome
MIs, cardiac conduction defects, and pts on MAOIs are CIs for this antispastic.
Cyclobenzaprine
This antispastic is an analog of diphenhydramine (Benadryl) with antihistamine, anticholinergic, euphoric, and analgesic properties and is used to treat acute muscle spasms associated w/acute MSK conditions.
Orphenadrine, has anticholinergic effects, not used that often
This antispastic used to be given for sleep, but it’s addictive and gets metabolized to meprobamate (anxiolytic and sedative effects)
Soma (meprobamate causes dependence, so it has withdrawal symptoms)
Probably shouldn’t be used in pregnancy
Newer antispastic that generally depresses the nervous system, used for relief of acute, painful, MSK conditions, and appears to cause less drowsiness than the others.
Metaxalone (skelaxin)
Watch for serotonin syndrome
Older antispastic that to suppress spinal polysynaptic reflexes, primary use is to TREAT MUSCLE SPASTICITY ASSOCIATED W/ TETANUS (TOXIN) POISONING
Methocarbamol
One of the AEs of this antispastic is urine discoloration (black, brown, or green)
Methocarbamol
This central a2 agonist reduces spasticity by increasing presynaptic inhibition of motor neurons…it’s short acting and causes some prominent drowsiness, adjust dose in hepatic/renal impairment.
Tizanidine (zanaflex)
GABA-mimetic at the spinal cord level, reduces calcium influx and the release of excitatory transmitters in both the brain and the spinal cord…can also reduce pain by inhibiting the release of substance P
Baclofen
This GABA agonist is the anti-spastic/DOC FOR MULTIPLE SCLEROSIS (MS). At least as effective as Valium, w/ less sedation and no loss of strength
Baclofen
GABA agonist, increases chloride influx, used as an anxiolytic, spasmolytic, antispasmodic, and antispastic
Diazepam (Valium)
Oral form of this drug is used in cerebral palsy, MS, muscle spasms, anxiety disorders, agitation, tremor, delirium, and alcohol withdrawal…risk of dependence/tolerance and a pregnancy class D
Diazepam (Valium)
Analog of GABA that does not directly impact GABA receptor, used to treat TONIC-CLONIC SEIZURES, NEUROPATHIC PAIN, POST-HERPETIC NEURALGIA, AND DIABETIC NEUROPATHY (off label)
Gabapentin (Neurontin)
Eliminated really…AEs = drowsiness, fatigue, dizziness
GABA derivative similar to gabapentin used to treat partial-onset seizures, neuropathic pain associated with a lot of stuff including diabetic neuropathy and FIBROMYALGIA
Pregabalin (lyrica)
This drug, eliminated really…AEs: drowsiness/fatigue greater than gabapentin
Pregabalin (lyrica)
Antispastic that interferes with excitation-contraction coupling in the muscle fibers, is the DOC IN THE TREATMENT OF MALIGNANT HYPERTHERMIA (MH)
Dantrolene sodium (Dantriun, Rynodex)
Dantrolene is not indicated for skeletal muscle spasm resulting from what type of disorders?
Rheumatic disorders (chorea, rheumatic fever, etc)
Between Dantrium and Rynodex, which has the fastest time to admin and which is more expensive?
Rynodex
Botulinum toxin type A is MC used for…
Cosmetic application
Non-cosmetic clinical use of botulinum toxin
Chronic migraines (2nd line agent), cervical dystonia, blepharospasm
What is the antidote to botulinum toxin?
Equine botulinum antitoxin