Exam 2 Questions (Part 2) Flashcards Preview

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Flashcards in Exam 2 Questions (Part 2) Deck (33):
1

Procaine (Novocain)

- Rapidly metabolized by blood cholinesterase to an allergen
- Allergic reactions occur
- Intermediate onset, short duration

2

Bupivacaine (Marcaine)

- Slow to intermediate onset, long duration of action
- Metabolized by CYP450 enzymes in liver
a. Slower rate than for esters
b. Good alternative if patients allergic to esters
- Duration prolonged if liver function impaired

3

Levobupivacaine (Chirocaine)

- active optical isomer of Bupivacaine (Marcaine)

4

Exparel

Long acting liposomal suspension approved for post surgical pain management

5

Lidocaine (Xylocaine)

- Rapid onset, intermediate duration of action
- Same metabolism pathway as bupivacaine
- Transdermal patch: Lidoderm

6

Peripheral Nerve Block

- Injection near nerve trunk
- Common for dental procedures, surgery on single extremity, etc

7

Epidural

- Space between bone and dura mater
- Large and accessible, route common for obstetrics
-Type of central neural block

8

Intrathecal

- Spinal Nerve Blockade: Subarachnoid Space
- Most effective
- Most dangerous
- Patient position and solution density determine area blocked

9

Central Nerve Blocks (General)

- Two types: Epidural and Intrathecal
- Postural headaches most common complaint
- Risk of hematoma if LMWH anticoagulants given concurrently

10

Sympathetic Block

- Sympathetic activity increases with complex regional pain syndrome
- Block usually occurs with central neural block, but can specifically inject area surrounding nerve chain ganglia

11

Diazepam (Valium): Skeletal Muscle Relaxant

- Increased GABA inhibition (via BZ and GABAA receptors) of 1a afferents (presynaptic) thus inhibiting hyperactive reflex arcs; of supra spinal center (sedation)
- Used for spasticity and muscle spasm
- Broadest spectrum of BZDs
- Sedation is a therapeutic benefit and side effect
- Long term concerns: dependence and withdrawal

12

Carisoprodol (Soma, Vanadem)
Cyclobenzaprine (Flexeril)

- Polysynaptic inhibitors (other centrally acting compounds)
- MECHANISM: spinal cord reflex inhibition and sedation
- USES: Often in combo with acetaminophen and aspirin
- ADVERSE: Drowsiness, dizziness, dependence, tolerance.
- Carisoprodol has an active metabolite, Meprobamate (Schedule IV)... avoid abrupt withdrawal

13

Baclofen (Lioresal)

- Used to treat spasticity
- Structurally similar to GABA
- GABA-B receptor agonist... inhibits release of excitatory neurotransmitters. Results in inhibition of alpha motor neuron activity in spinal cord and pain pathways. Relaxation of skeletal muscle and some analgesia
- Drug of choice for MS
- ADVERSE: Drowsiness, muscle weakness, withdrawal syndrome

14

Intrathecal Administration for Baclofen (Lioresal)

- Injection in subarachnoid space surrounding spinal cord
- Programmable pump system
- Maximize benefit (including analgesia), minimize side effects
- Drawbacks
a. Malfunction of pump system
b. Tolerance require dose increase over time
c. Severe withdrawal syndrome possible: merits black box warning

15

Dantrolene (Dantrium)

- Inhibits Calcium release from sarcoplasmic reticulum in skeletal muscle cells (RyR Antagonist); inhibits muscle contraction
- Indicated for severe spasticity regardless of cause, CVA, CP, spinal cord lesions, MS, malignant hyperthermia
- Adverse Effects: Generalized muscle weakness, hepatotoxicity

16

Gabapentin (Neurontin)

- Mechanism: Enhances GABA activity (antiseizure)
- Uses: Good in combination with others; also indicated fro chronic pain

17

Tizanidine (Zanaflex)

- Mechanism: Alpha 2 receptor agonist
- Related to clonidine, but less BP effects
- Inhibitory actions in spinal cord
a. Presynaptic inhibition of excitatory interneurons
b. Decreased activity of alpha motor neurons
- Sedation and dry mouth similar to clonidine

18

Botulinum Toxin

- Mechanism: Binds to presynaptic vesicles and inhibits release of ACh; produces paralysis rather than relaxation
- Uses: Indicated for dystonias and other specific muscle spasms; local injection paralyzes specific muscles
- Also approved to treat excess sweating, wrinkles, chronic migraine, and urinary incontinence in patients with spinal injuries
- Drawbacks: effects wear off in 2-3 months; limited number of muscles may be treated in a given session
- CAUTION: May spread from injection site

19

Tubocurarine (Curare)

- Nondepolarizing blocker (receptor antagonist)
- Competitive, reversible Nm receptor antagonist.
a. physically blocks ion channels associated with N receptors
b. actions can be reversed by ACh
c. No effect on M receptors
- Muscle Paralysis Order: Head and neck, limbs, respiratory muscles
- Adverse effects: Histamine release, hypotension, inhalation anesthetics and certain antibiotics enhance NMJ blockade

20

Antidotes to Curare

- AchE Inhibitors
- Sugammadex (Bridion)

21

Endogenous Opioid Peptides

- Inhibitory transmitters which modify most aspects of pain transmission and perception.
- Modulate hormonal fluctuations, thermoregulation, stress, anxiety, GI function, pain
- Three families of peptides have been identified
a. Pentapeptides (met and leu-enkephalin)
b. Dynorphins
c. Endorphins

22

Opioid Mixed Agonists/Antagonists

PROTOTYPES
- Butorphanol (Stadol)
- Buprenorphine (Buprenex, Butrans)

GENERAL
- Analgesia due primarily to Kappa receptor activity
- Only partial agonists or antagonists at mup receptor
a. may displace stronger agonists from mu receptor sites
b. may precipitate withdrawal in addicts
- Mized receptor activity results in "ceiling" (less efficacious) analgesic and respiratory depression with decreased dependence liability

ADVERSE SIDE EFFECTS
- Dysphoria
- Anxiety
- Hallucinations

23

Opioid Antagonist Prototypes

PROTOTYPES
- Naloxone (Narcan) iv
- Naltrexone (ReVia) po

GENERAL
- Pure competitive antagonists: highest affinity for mu receptors
- Used to treat overdoses, accelerate postop recovery, or treat dependence
- Precipitate withdrawal syndrome in opioid addicts

24

Prototype Opioid Analgesic

Prototype: Morphine

PHARMACOLOGICAL ACTIONS: CNS
- General
a. With Pain: Analgesia, euphoria, drowsiness, mental clouding
b. Without Pain: Nausea, apathy, dysphoria prominent
- Analgesia
- Pupillary Constriction (good indicator of abuse; no tolerance)
- Respiratory Depression
- Suppression of Cough Reflex
- Nausea and vomiting via stimulation of chemoreceptor trigger zone in brainstem

GI TRACT
- Decreases glandular secretions
- Decreases propulsive peristalsis, increases non-propulsive contractions
- Increase biliary tract pressure

GENITOURINARY TRACT
- Increase bladder detrusor and sphincter tone: urinary retention and exacerbation of pain due to kidney stones
- May prolong labor

PHARMOKINETICS
- Erratic po absorption: extensive first pass metabolism
- easily crosses placental barrier and fetal BBB
- Hepatic Metabolism: active metabolite

ADVERSE EFFECTS
- Tolerance: lack of effectiveness after repeated dosing
- Dependence: Higher doses required for sufficient pain relief: lacrimation, chills, goosebumps, hyperthermia, mydriasis, anxiety, hostility
- Overdose: Stupor, coma, respiratory depression, hypotension

25

Naloxone (Narcan, iv)

- Opioid antagonist
- Occupy opioid receptor without producing a pharmacological effect
- Reverse CNS and GI effects of morphine
- Several injections may be required (1 hr half life)
- May precipitate sudden and intense withdrawal in opioid addicts

26

Naltrexone (Vivitrol)

- Opioid antagonist
- Given po, longer half life (10 hours)
- Indications: opioid dependence, apnea in children, alcohol dependence

27

Methadone

- Similar to morphine, with longer duration of action and a longer, but less intense withdrawal syndrome
- Used primarily in heroin detoxification and maintenance programs

28

Meperidine (Demerol)

- More consistent oral absorption than morphine
- Primary Metabolite: Normeperidine
a. May produce CNS excitation and convulsions
b. Less respiratory depression than morphine
- Fewer GI and GU tract effects
- Indicated for labor pain

29

Fentanyl (Sublimaze)

- Anesthesia
a. Adjunct: Sedative, anxiolytic and analgesic properties
b. Used alone for certain types of CV surgery
c. Regional analgesia via direct injection into epidural spaces of the spinal cord (morphine also used)
- Transdermal system available for chronic pain (Duragesic)
- Iontophoretic system (Ionsys)
- Buccal/Transmucosal Admin: Lollipop (Actiq)

30

Partial Mu Agonists with Lower Maximum Efficacy

Codeine
- metabolized in part to morphine
- genetic variation in the P450 enzyme producing morphine result in decreases or increases in analgesic and respiratory depressant effect

31

Oxycontin

- Oxycodone controlled release form
- To be swallowed whole to release drug over 24 hour
- Extensive abuse

32

Targiniq ER

- Oxycodone + naloxone
- Designed to prevent abuse via inhalation or injection

33

Tramadol (Rybix, Ryzolt, Ultram)

- Weak mu agonist, strong inhibitor of NE/5HT reuptake
- Unique adverse effect: seizures
- Caution: May cause respiratory depression in children