Muscle relaxants

  1. MOA CNS sedatives/depressants

    Metalaxone (Skelaxin)
    Methocarbamol (Robaxin)
    Chlorzoxazone (paraflex, parafon forte)
    • exact MOA unknown
    • -does not work on skeletal muscle or neuromuscular juntion
    • -achieve effect by sedation
    • - do not have analgesic or anti-inflammatory effects

    -Does reduce involuntary muscle contractions and muscle spasms from skeletal injury.

    DO NOT treat spasticity by CNS disease
  2. Methocarbamol (Robaxin) can cause
    CNS depression
  3. Chlorzoxazone (Paraflex, parafon forte) acts at the....
    spinal cord and subcortical levels.  Inhibits reflex arc.
  4. C
  5. Carisoprodol (Soma) is metabolized to....

    • meprobamate (similar to barbiturates)
    • but blocks interneuronal activity in descending reticular formation and spinal cord.
  6. TCA relatives  - Cyclobenzaprine (flexeril) MOA
    acts on CNS to reduce tonic somatic motor activity.

    Causes reserpine antagonism, nor epi potentiation, potent anticholinergic effects and sedation
  7. Benzodiazepines MOA
    direct skeletal muscle relaxant action in brainstem and spinal cord level.  Enhances GABA mediated inhibition.

    May be useful for muscle spasm and spasticity caused by upper motor neuron disorder.
  8. What is the only Benzo for muscle spasms
    Diazepam (Valium)
  9. a2-adrenergic Receptor Angonist- Tizanidine (zanaflex) MOA
    is related to clonidine and has central mediated myospasmolytic action.  Lowers gastric acid secretion.  Effective for both CNS and non CNS spasms.
  10. GABA receptor Stimulant (Baclofen)  MOA
    is only for muscle spasm caused by CNS disease
  11. What to tx short term low back pain
    NSAIDS are effective with acetaminophen and skeletal muscle relaxants
  12. What is first line muscle relaxant
    Cyclobenzaprine (CAS)- central acting sedative
  13. Tx for acute injury
    rest and ice for 24-48 hours
  14. Treat chronic muscle spasm with
  15. Skeletal muscle relaxants should not be used for longer than _____
    2 weeks
  16. Always do what before providing tx for any back injury
    do rectal exam
  17. What is the only drug with direct muscle relaxant effects

    Use short term because of abuse potential
  18. Monitor patient while on these drugs for
    • watch for reduction in spasms
    • sedation and dizziness
    • Abuse or abuse potential
    • give in limited amounts

    Monitor LFTs in pts at risk
  19. Geriatrics and these meds
    • increased risk of sedation
    • increase risk of falls
    • driving can make LBP worse, use lumbar supporst
  20. Safety and these drugs in children under 12 and pregnancy
    not been established
  21. Patient education
    • may cause sedation and decrease mental alertness
    • do not drink ETOH or other CNS depressants due to addictive effects
    • notify md of skin rash or jaundice
  22. Tizanidine and acetaminophen

    Tizanidine and Cipro

    Tizanidine and fluvoxamine

    Tizanidine and ETOH
    delays action of acetaminophen

    Cipro may increase levels of Tizanidine. concurrent use is not advised

    fluvoxamine may increase risk of Tizanidine

    ETOH enhances blood levels of tizanidine
  23. Drugs such as ketoconazole, norfloxacin, ofloxacin, and rofecoxib are ______ with all of these type of drugs
Card Set
Muscle relaxants
pharm fall 2013