SKELETAL MUSCLE RELAXANTS

Relieve muscular spasms and pain associated with traumatic injuries and spasticity from chronic debilitating disorders

Spasticity results from increased muscle tone from hyper excitable neurons caused by increased stimulation from the cerebral neurons or lack of inhibition in the spinal cord or at the skeletal muscles.

Muscle Relaxants

CENTRAL ACTING MUSCLE RELAXANTSAre used in cases of spasticity to suppress

hyperactive reflex and for muscle spasms that do not respond to anti-inflammatory agents, physical therapy or other forms of therapy.

Centrally acting muscle relaxants acts on the spinal cord.

SPASTICITYIs muscular hyperactivity that causes contractions

of the muscles, resulting in pain and ,limited mobility.Ex. Of centrally acting muscle relaxants that treat

spasticity are baclofen (Lioresal), dantrolene (Dantrium), and tizanidine (Zanaflex). Diazepam (Valium), a benzodiazepine has also been effective for treating spasticity

MUSCLE SPASMSVarious centrally acting muscled relaxants are

used for muscle spasms, to decrease pain and increase range of motion.

They have a sedative effect and should not be taken concurrently with CNS depressants such as barbiturates, narcotics, and alcohol

Dizziness and drowsiness are common side effects.

Examples of this group of centrally acting muscle relaxants are carisoprodol (soma), chlorzoxazone (Paraflex), cyclobenzaprine (flexeril), metaxalone (skelaxin), methocarbamol (Robaxin), and orphenadrine citrate (Norflex).

Diazepam (Valium)Diazepam has many uses, one of which is to

relive muscle spasms associated with paraplegia and cerebral palsy.

contraindicated in narrow-angle glaucoma.

Meprobamate (miltown)Has a muscle relaxant effect

Anxiolytics

baclofen (lioresal)For muscle spasms casued by MS and spinal cord

injury.Overdose may cause CNS depression.

Drowsiness, dizziness, nausea, hypotension may occur.

Tizanidine (zanaflex)To manage spasticity, especially for spinal cord

injury and multiple sclerosis.

Spasticity a. centrally acting

Dantrolene sodium (dantrium)For chronic neurologic disorders causing spasms,

spinal cord injuries, stroke, MS.Start with low doses and increase every 4 to 7

day.Avoid taking with alcohol and CNS depressants.

b. Direct acting

Carisprodol (soma)To relax skeletal musclesBlocks interneuronal activityIncrease CNS depression with alcohol, narcotics,

sedative-hypnotics, anti-histamines, tricyclic anti-depressants.

May increase risk for ventrivular fibrilation with calcium channel blockers.

Contraindicated with severe renal or renal disease.Side effects are nausea, vomitting, dizziness,

weakness, insomniaAdverse reactions are asthmatic attack, tachycardia,

hypotension, diplopia.

Centrally Acting Muscle Relaxants

Chlorzoxazone (paraton forte)For acute of severe muscle spasms.Not effective for cerebral palsy.Take with food to decrease GI upset.

Cyclobenzaprine HCL (flexiril, cycloflex)For short term treatment of muscle spasmsNot effective for relieving cerebral or spinal cord

disease.Take with food to reduce GI upset.

Methocarbamol (robaxin, marbaxin)For acute muscle spasms, drug used for treatment of

tetanusHas CNS depressant effects. Avoid taking alcohol or

CNS depressants. Urine may be green, brown or black. Drowsiness that may occur usually decrease with continued drug use.

Metaxalone (skelaxin)For acute painful muscle spasticity

Orphenadrine citrate (norflex, flexon)For acute muscle spasm, can be toxic with mild

overdoseUsed in combination with aspirin and caffeine.

(norgesic)

Pancuronium bromide (pavulon)Used in surgery for relaxation of skeletal muscleConsidered to be five times as potent as

tubocurarine chloride.Does not cause hypotension or bronchospasm

Succinylcholine Cl (anectine Cl. Quelion, sucostrin)used in surgery with anesthesia for skeletal

muscle relaxationAlso used in endoscopy and intubation.

Depolarizing Muscle Relaxants (Adjunct to Anesthesia)

Vecuronium bromide (norcuron)Used is similar as succinylcholine chloride.Can be used for clients with asthma, renal

disease, or limited cardiac reserveGiven after general anesthesia has been started.

Tubocurarine ClAdjunct to general anesthesiaTo induce skeletal muscle relaxation