MOA CNS sedatives/depressants
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
Methocarbamol (Robaxin) can cause
Chlorzoxazone (Paraflex, parafon forte) acts at the....
spinal cord and subcortical levels. Inhibits reflex arc.
Carisoprodol (Soma) is metabolized to....
- meprobamate (similar to barbiturates)
- but blocks interneuronal activity in descending reticular formation and spinal cord.
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
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.
What is the only Benzo for muscle spasms
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.
GABA receptor Stimulant (Baclofen) MOA
is only for muscle spasm caused by CNS disease
What to tx short term low back pain
NSAIDS are effective with acetaminophen and skeletal muscle relaxants
What is first line muscle relaxant
Cyclobenzaprine (CAS)- central acting sedative
Tx for acute injury
rest and ice for 24-48 hours
Treat chronic muscle spasm with
Skeletal muscle relaxants should not be used for longer than _____
Always do what before providing tx for any back injury
do rectal exam
What is the only drug with direct muscle relaxant effects
Use short term because of abuse potential
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
Geriatrics and these meds
- increased risk of sedation
- increase risk of falls
- driving can make LBP worse, use lumbar supporst
Safety and these drugs in children under 12 and pregnancy
not been established
- 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
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
Drugs such as ketoconazole, norfloxacin, ofloxacin, and rofecoxib are ______ with all of these type of drugs