Question | Answer |
What are skeletal muscle relaxants used for? | relief of musculoskeletal pain, spasm, and severe spasticity such as in multiple sclerosis, cerebral palsy, stroke, and spinal cord injuries |
Define multiple sclerosis. | progressive demyelization of the white matter of the brain and spinal cord resulting in widespread neurologic dysfunction |
Define cerebral palsy | motor function disorder caused by neurologic damage usually incurred during the peri-natal period or the first two years of life often associated with hypoxia |
What are the two main classes of skeletal muscle relaxants? | centrally acting and direct acting |
Describe “cycling” as it relates to muscle spasms. | an impulse such as severe cold, lack of blood flow, or overexertion causes a muscle to send messages to the CNSsetting a reflexive muscle contraction. The muscle contraction further stimulates sensory receptors resulting a more intense contraction. |
How do centrally acting muscle relaxants work to treat muscle spasms? | the act as sedatives in the CNS |
Which centrally acting muscle relaxant is prescribed for chronic and intermittent spasms? | tizanidine |
Name 7 centrally acting muscle relaxants that might be used to treat acute muscle spasms. (CCCMMOT) | Carisoprodol, Chlorzoxazone, Cyclobenzaprine, Metaxalone, Methocarbamol, Orphenadrine, Tizanidine |
Say Carisoprodol. | Care s soap pro dull |
Say chlorzoxazone. | Chlor ZOX uh zone |
Say Tizanidine. | Tie Zan uh deen |
How long do centrally acting muscle relaxants take to work? | 30 minutes to 1 hour |
How long do centrally acting muscle relaxants last? | 4-6 hours except cyclobenzaprine |
Which centrally acting muscle relaxant can last from 12 – 25 hours? | cyclobenzaprine |
What are the big interactions, adversities to be aware of with centrally acting muscle relaxants? | they are CNS depressants so would have cumulative effects with other CNS depressants – Watch for respiratory depression, sedation, impaired motor function |
What are some other CNS depressants our patients on centrally acting muscle relaxants should avoid? | alcohol, narcotics, barbiturates, anticonvulsants, tricyclic antidepressants, kava kava, antianxiety drugs |
What could result if centrally acting muscle relaxants are taken with MAOIs? | high body temperature, excitation, seizures |
What’s the problem with combining cyclobenzaprine and blood pressure lowering drugs guanethidine or clonidine? | cyclobenzaprine can cause them not to work effectively |
What can happen as a result of the combination of cyclobenzaprine or orphenadrine and cholinergic blocking drugs? | enhanced effect of the cholinergic blocking drug |
What can happen as a result of the combination of methocarbamol and anticholinesterase drugs used to treat myasthenia gravis? | methocarbamol can block the effects of the anticholinesterase drug |
What can happen if orphenadrine and propoxyphene are combined? | additive CNS effects such as confusion, anxiety, and tremors |
Discuss the interactions we should watch for if our patient is taking tizanidine. | with diuretics, central alpha agonist or antihypertensive possible hypotension; with CNS depressants increased CNS depression; with hormonal contraceptives reduced clearance of tizandine = decreased dosage required |
What do we need to know about long term use of centrally acting muscle relaxants? | They can cause physical psychological dependence – abrupt cessation will produce severe withdrawal symptoms. |
Name two common adverse reactions associated with centrally acting muscle relaxants. | Dizziness, drowsiness |
Name 6 occassional adverse reaction to centrally acting muscle relaxants. | abdominal distress, constipation, diarrhea, heartburn, nausea, vomiting, ataxia |
Define ataxia. | loss of ability to control muscular movement |
Name 3 severe reactions to centrally acting muscle relaxants. | allergic, arrhythmias, bradycardia |