Drugs for Muscle Spasms and Spasticity 2-3

Question 1

muscle spasm

Answer 1

-muscle spasm: sudden involuntary contraction
(due to epilepsy, hypoCa, pain syndromes, trauma)

treatments: either or
-central: Cyclobenzaprine or Valium
-peripheral: physical measures or Analgesia (NSAIDS)

Question 2

muscle spaticity

Answer 2

-spasticity: heightended muscle tone, spasm, loss dexterity
(due to SCI, MS, cerebral palsy)

treatments: either or
-central: Baclofen or Valium
-peripheral: physical therapy or Dantrolene

Question 3

non-pharm treat

Answer 3

-immobilize affected
-cold compress
-whirlpool baths
-physical therapy

Question 4

Cyclobenzaprine (Flexeril)

Answer 4

-MOA: centrally-acting muscle relaxants (local)
-PO
-for muscle spasm

Question 5

Cyclobenzaprine adverse

Answer 5

-CNS depression
-hepatotoxic (rare)
-cardiac ryhthm disturbances
-anti ACh effects: constipation, urine retention, hypotn, tachy, resp depression

-can cause physical dependence –> withdraw over 2 weeks

Question 6

Cyclobenzaprine intx and toxicity

Answer 6

-no alcohol or CNS depressants
-no SSRI, MAOI, tricyclic antidepressants: induce sertonin syndrome

-s/s of toxicity:agitation, drowsy, confusion, nv, hallucinations, slurred speech, NMS (high fever, rigid)

Question 7

Diazepam (Valium)
(for both muscle spasm and spasticity)

Answer 7

-MOA: centrally-acting benzodiazepine –> enhance GABA effects
-muscle relaxant acutely (for muscle spasms) (also an antispasmodic)
-physical and psychlogical dependence

-clearance decreased by liver dysfunction: monitor LFT

==> antidote: Flumazenil: benzo-receptor blocker

Question 8

Baclofen (Lioresal)

Answer 8

-MOA: centrally-acting; act at spinal end upper motor neuron to hyperpolarize
–> reduce impulse formation
–> suppress hyperactive reflexes
–> mimics GABA on spinal neurons
-for muscle spasticity (NOT effective for spasms in CVA, parkinsons, huntingdons)

-withdraw slowly

Question 9

Dantrolene

Answer 9

-MOA: peripherally-acting spasmolytics –> reduce excitation and contraction by interfering with Ca intercellular movement
-drug of choice for malignant hyperthemia
-acts directly on skeletal muscles

-for muscle spasticity (dont give it if they need rigidity to maintain posture)

Question 10

summary

Answer 10

for muscle spasm: Cyclobenzaprine (central), Diazepam (central), analgesia (perph) or physical (perph)

for muscle spasticity: Baclofen (central), Diazepam (central), physical and Dantrolene (perph)

-all centrally acting (Cyclo, Bac, Diaz) produce CNS depression –> dont take with CNS depressants (ex: antihistamines)
-all centrally acting also cause physical dependence