Ch 27: Skeletal Muscle Relaxants

Question 1

neuromuscular blockers

Answer 1

can get muscle relaxation w/out deep depression

Question 2

effects of neuromuscular blockers

Answer 2

• 1st cause muscle weakness, then flaccid & unexcitable
• larger muscles more resistant & recover quicker (diaphragm last)

act as:
depolarizing agents
non-depolarizing agents

Question 3

depolarizing agents

Answer 3

• can cause arrhythmia (stimulates mus. & Nic receptors of heart… decrease inotropicity & chronotropicity)
• Succinylchlorine: paralysis takes 1 minute

Question 4

non-depolarizing agents

Answer 4

• can cause hypotension (hist. release; give w/ antihistamine)
• Vecuronium, doxacurium

Question 5

Spasmolytics

Answer 5

can reduce spasticity & spasms

Question 6

Spasticity

Answer 6

abnormal stretch reflex, especially. w/ rapid lengthening of muscle: appears mostly due to “higher centers” (upper motor neuron lesion)

Question 7

Spasms

Answer 7

afferents from damaged muscle tissue excites outflow from alpha motor neurons

Question 8

Centrally acting agents

Answer 8

Diazepam
Baclofen
Tizanidine

Question 9

Direct acting agents

Answer 9

Dantrolene sodium (Dantrium)
Botulinum toxin (botox)

Question 10

Diazepam

Answer 10

facilitates GABA-a activity
- causes sedation (problem)

• useful w/ spasms/spasticity (acts in the cord)
• causes sedation, hangover, tolerance

Question 11

Baclofen

primary agent for spasticity

Answer 11

(beta-chlorophenyl- GABA)

• activates GABA in cord & increases K+ conductance (hyperpolarization)
• inhibits alpha motor activity
• given orally or intrathecal to subarachnoid space near affected area (can have problems w/ delivery system {pump, catheter} & tolerance)

Question 12

Side effects of Baclofen

Answer 12

initial drowiness
fatigue
headache

Question 13

Tizanidine

Answer 13

alpha 2 adrenergic agonist

- reinforce pre- and post-synaptic inhibition in cord

Question 14

side effects of Tizanidine

Answer 14

drowsiness
hypotension
dry mouth

(studies show equal efficacy as diazepam, baclofen & dantrolene in several types of spasticity)

Question 15

Dantrolene sodium (Dantrium)

primary use for MS

Answer 15

• inhibits calcium release from SR in “excited” muscle cells

- block receptor site on SR that opens the channels that calcium exits (ryanodine site)

Question 16

side effects of Dantrolene sodium (Dantrium)

Answer 16

generalized muscle weakness
drowsiness
dizziness
- severe hepatotoxicity

Question 17

Botulinum Toxin (Botox)

Answer 17

• binds ACh- containing vesicles and prevents exocytosis
  can be injected into muscles
  (takes days- weeks to elicit effect, last 2-3 months)
• for spasmodic torticollis
  laryngeal dystonia

Question 18

Gabapentin

Answer 18

used in conjunction with other meds

- GABA-mediated inhibition of alpha motor n.

Question 19

Opioid Analgesics

Answer 19

“without pain” (pain relief)

- sometimes called narcotic analgesics or narcotics

Question 20

morphine

Answer 20

was once known to be a analgesic
- comes from a poppy seed after flowers fall off
(white latex, which is sticky and thick) is the “crude” opium

Question 21

opioid receptor types

Answer 21

Mu
delta
kappa

(agonists of these receptors either block Ca2+ entry presynaptically {no transmitter release} or increase K+ conductance {hyper polarize cells})

Question 22

Mu

Answer 22

analgesis
respiratory depression
dependence

Question 23

Delta

Answer 23

analgesia at spinal level

Question 24

kappa

Answer 24

analgesia at spinal level

Question 25

Effects of opioid agonists

Answer 25

analgesia
euphoria
sedation
respiratory depression
cough suppression
miosis
trunk rigidity
reduce GI motility rate

Question 26

analgesia

Answer 26

reduce pain in sensory and affective (emotional) components

Question 27

euphoria

Answer 27

pleasant, floating sensation
(free from anxiety & distress)
- can give dysphoria during/when stop taking

** can bring addicts back

Question 28

sedation

Answer 28

drowsiness

Question 29

cough suppression

Answer 29

reduce activity at cough “centers”

Question 30

miosis

Answer 30

pupil constriction (seen in addicts; no tolerance to this)

Question 31

trunk rigidity

Answer 31

increase tone of large trunk muscles

can block w/ neurons muscle blockers

Question 32

reduce GI motility rate

Answer 32

can be constipating/ used to reduce severe diarrhea

Question 33

Uses for opioid analgesics

Answer 33

analgesia
(use of morphine and others to reduce pain)

acute pulmonary edema
(slow breathing & shortness of perception of shortness of breath & anxiety)

cough
(use of dextramethorphan)

diarrhea
(slows GI motility .. esp. Loperamide)

pre-anesthesia
(sedating, anxiolytic, analgesic)

Question 34

opioid side effects

Answer 34

tolerance
physical dependence
psychological dependence

Question 35

tolerance

Answer 35

” need higher doses”

esp. analgesic, euphoric, and resp. depression

Question 36

physical dependence

Answer 36

“rebound” effect opposite to acute administ

- hyperventilation, diarrhea, anxiety, hostility

Question 37

psychological dependence

Answer 37

“NEED” to take to reserve disphorea

Question 38

opioid agents

Answer 38

agonists

antagonists

Question 39

agonists

Answer 39

• strong agonist
  (morphine, methadone, fentanyl, levorphanol. For severe pain) –> act as mu and kappa
• mild/mod agonist
  codeine, hydrocodone, oxycodone, loperamide (lower efficacy at mu and kappa)
• mixed agonist/antagonist
  butorphanol, pentazocine
  adequate analgesia, less tolerance and dependence, less resp depression and O.D. Activate kappa and sigma, block mu

Question 40

antagonists

Answer 40

naloxone

naltrexone (for O.D.)