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Pharmacology II > Pain Management > Flashcards

Flashcards in Pain Management Deck (57):
1

What are the steps of processing pain?

1. Transduction (stimulation of the nociceptors)

2. Conduction

3. Transmission (Pain traveling up spinal cord)

4. Perception

5. Modulation

2

What is the cause of sharp, well-localized pain?

-large diameter
-sparsely myelinated fibers

3

What fibers are involved with aching, poorly localized pain?

-small-diameter
-unmyelinated

4

Somatic Pain

-from skin, bone, joint, muscle, connective tissue

-throbbing, well localized

5

Type of pain from large-diameter sparsely myelinated Alpha and Delta

sharp, well-localized pain

6

Type of pain from unmyelinated, small-diameter C fibers

dull, aching, poorly localized

7

Where is the blockade of N-methyl-D-aspartate (NMDA) receptors found

dorsal horn

8

Central sensitization

-increase in excitability or responsiveness of neuron within the CNS

-Associated with inflammatory pain after injury

9

Neuropathic pain

nerve damage

ex. post-herpetic neuralgia, diabetic neuropathy

10

Functional pain

abnormal operation of nervous system

ex. Fibromyalgia, IBS, tension-type headache

11

Non-pharmacologic therapy for pain

-physical manipulation
-heat or cold
-massage
-exercise
-TENS (transcutaneous electrical nerve stimulation)
-cognitive and behavioral

12

Pain - PPQRST

Palliative
Provocative factors
Quality
Radiation
Severity
Temporal

13

Treatment goal difference between acute and chronic pain?

acute - pain reduction

chronic - functionality

14

Salicylates

1. Acetysalicylic acid (ASA)
-irreversibly binds to platelets for 7-10 days

2. Choline and magnesium trisalicylate
-no acetyl group, doesn't alter platelets

3. Diflunisal
-no acetyl group, doesn't alter platelets

15

Non-opioid analgesics

1. Salicylates
2. Acetaminophen
3. anthranilic acid (ex. Mefenamic acid)
4. Indolacetic Acid ( ex. Etodolac)
5. Phenylacetic acids (ex. Diclofenac)
6. Propionic Acids (ex. Ibuprofen, Naproxen)
7. Pyrrolacetic acids (ex. Ketorolac (toradol))
8. Cox-2 selective (ex. Celecoxib)

16

Acetaminophen max dosing

Elderly: max of 2gm/day
-Normal adults: max of 3gm/day

17

Phenylacetic Acids

Diclofenac potassium

Diclofenac epolamine, (patch)

Diclofenac sodium (topical gel, for osteoarthritis)

18

Propionic acids

1. Ibuprofen (max daily dose for inflammation: 3200mg, max dose of fever/dysmenorrhea: 1200mg)

2. Naproxen - osteoarthritis; Naproxen sodium for acute pain

19

Pyrrolacetic Acids

1. Ketorolac (Toradol) Parenteral max of 5 days

2. Oral ketorolac - max of 5 days

3. Nasalspray ketorolac: one spray, in one nostril. Max of 5 days

20

Celecoxib and ASA

If using low dose ASA in a patient, give it before the Celecoxib

21

NSAIDS: adverse reactions and monitoring

1. Upper GI bleed
-monitor with CBC, stool guaiac

2. Acute Renal Failure
-monitor serum creatinine (esp. if CHF, hypovolemia)

22

Acetaminophen: adverse reactions and monitoring

1. Hepatotoxicity
-ALT/AST
-Liver synthesis tests
-PT/INR, albumin
-Acetaminophen concentration

23

Opioids: Phenanthrenes - Potency

Greatest to least potency:

Oxymorphone
Hydromorphone (Dilaudid) (1.5 x weaker than oxymorphone)
Morphine (10x weaker than oxymorphone)
-morphine PO has the greatest first pass effect (ex. have to give 3x the dose orally)
-Codeine 15-30x weaker than Oxymorphone
-Hydrocodone 30x weaker
-Oxycodone 30x weaker

24

Opioids: Phenanthrenes - Relative histamine release

Morphine (naturally occuring) +++

Hydromorphone (semi-synthetic) +

Oxymorphone (semi-synthetic) +

Codeine +++

Levophanol (semi synthetic) +

Hydrocodone (Vicodin) N/A

Oxycodone (OxyContin) (semi-synthetic) +

25

Morphine

**drug of choice in severe pain**

For cancer patients: can use immediate-release product with controlled release product to control breakthrough pain

-can cause sphincters to close more tightly, sometimes causing more pain

26

Hydromorphone (Dilaudid)

more potent than morphine, otherwise no advantages

27

Oxymorphone (Opana)

Most potent Phenanthrene
-can use immediate + controlled release for cancer pt.
-ER reformulated to deter misuse

28

Codeine (methylmorphine) General

-Mild to moderate pain and cough suppression
-Needs CYP450, 2D6 to metabolize to morphine (prodrug metabolize to morphine)**

DON'T use in children or with breastfeeding

29

Phenylpiperidines: General

1. Meperidine (Demerol)

Histamine: +++
Strength: 100x weaker
-DON'T use, toxic metabolite accumulation can cause seizures

2. Fentanyl (sublimaze, Duragesic Actiq)

Histamine: +
Strength: 0.1x weaker**

30

Phenylpiperdines: Meperidine (Demerol)

DON'T USE:
-oral form
-in renal failure

**May precipitate tremors, myoclonus, seizures***

**Dilates eye (mydriasis) not constriction (miosis)

*can cause serotonin syndrome with MOAIs

31

Phenylpiperdines: Fentanyl

-Don't use the transdermal patch for acute pain (dose too low)

-Transmucosal, intranasal, sublingual

32

Diphenylheptanes: General

Methadone

histamine: +
Dose: variable!!**

ADE: QT prolongation*****
avoid titrations more frequently than every 2 weeks

33

Agonist-Antagonist (these contain Naloxone)

1. Pentazocine (historical, not used today)
-3rd line agent


These are 2nd line:
2. Buprenorphine
dose: 0.3x weaker than oxymorphone
-may not be effecting in reversing respiratory depression

3. Nalbuphine
4. Butorphanol


**May precipitate withrdrawal in opiate-dependent patients

34

Opioid Analgesics: Central analgesics

1. Tramadol
dose: 120x weaker than oxymorphone
-can be helpful for neuropathic pain
-Pro-drug, must be converted to produce analgesia

-Risk of seizure, serotonin syndrome, hypoglycemia

***Decrease dose in elderly (75+) and renal impairment**

35

Analgesic Drug monitoring

1. Respiratory depression
-respiratory rate, end-tidal capnography*
-The newer a patient is to opioids more likely they are to have this
-Sleep apnea, COPD at higher risk

2. Constipation
-use Bristol scale to assess

36

Opioids: ADEs

Sedation, Nausea, vomiting: will decrease over time

Hypogonadism: fatigue, depression, sexual dysfunction, amenorrhea

Sphincter: monitor for biliary spasm, urinary retention

37

Opioid antagonist: Naloxone

-synthetic
-IV
-duration is shorter than opioid so need to repeat dose*

38

Neuropathic pain

-Chronic type of pain
Treatments:
1. Anticonvulsants
2. TCA
3. SNRI
4. Opioid
5. Topical analgesics

39

Chronic Pain: Anticonvulsants: Gabapentin [neurontin]

-decreases neuronal excitatory neurotransmitters by affecting voltage-gated calcium channels

ADE: Dizziness, fatigue, peripheral edema, tremor, headache, amnesia, ataxia, weight gain

40

Chronic Pain: Anticonvulsants: Pregabalin [lyrica]

-structurally related to GABA, but doesn't bind to GABA receptors

-Antinociceptive and anticonvulsant activity
**peripheral neuropathy**

ADE: peripheral edema**, weight gain, tremor, dizziness

41

Chronic pain-Adjunctive therapy: TCA, SNRI, Duloxetine

block reuptake of serotonin and norepinephrine enhancing pain inhibition

42

Mild pain treatment

Acetaminophen +/- NSAID

43

Moderate pain treatment

Opioid + acetaminophen or NSAID

44

Severe Pain treatment

Opioid

45

which 2 opioid analgesic drugs are prodrugs

1. Codeine
2. Tramadol

46

What is the caution with using agonist/antagonist agents?

can produce opioid withdrawal in patients chronically taking opioid

47

Why should you avoid Meperidine?

short duration so frequent dosing
-toxic metabolite normeperidine (seizures)

48

What is the drug of choice for focal neuropathic pain?

Lidocaine

49

Intrathecal

injected into the spinal column subarachnoid space

-indicated for cancer-related pain

Ex. Morphine or Fentanyl

50

Epidural route

Ex. Morphine
Hydromorphone
Fentanyl
Sufentanil


-can do continual infusion with this route*

51

Ziconotide

MOA: unique mechanism, no action on the mu receptor

First line therapy for localized and nociceptive pain

52

What is the treatment algorhythm for low back pain

1. heat, massage, acupuncture, CBT
2. NSAIDs and skeletal muscle relaxants (acute <4 weeks)
3. Chronic low back pain (>12 wks) NSAIDs are 1st line. Duloxetine, Tramadol are 2nd line

53

Neuropathic pain: treatment

1st line: TCA, SNRI, AED, lidocaine patch

2nd line: central analgesics, opioids

3rd line: capsaicins

--NSAID and acetaminophen - rarely effective

54

Heroine

-Diacetylmorphine (give the euphoric feeling, helps cross the BBB)

-metabolized to morphine

55

Opioids: What is thought to represent true allergy only

Bronchospasm
and sometimes angioedema

-severe angioedema
-severe hypotension

56

Pseudoallergy

-mast cell degranulation
-itching, flushing, sweating, mild hypotension

**depends on the concentration of the opioid at the mast cell

57

Which opioids are most commonly associated with pseudoallergy?

-codeine
-morphine
-meperidine


**more potent opioid, less likely to release histamine**