Pharmacotherapy of Severe Pain & Migraines

Question 1

Goal of Pain Management

Answer 1

reduce pain to a level that allows a pt to perform reasonable ADL’s

Question 2

Key Principles of Pain Management

Answer 2

1. pt should be considered expert of their own pain
2. pain management is a pt right and should be based on pt goals
3. nonpharmacologic interventions should be encouraged in addition to pharmacotherapy
4. dosing should be individualized/adjusted
5. adverse effects should be anticipated & PREVENTED whenever possible

Question 3

Is it easier to manage pain or prevent it?

Answer 3

Around-the-clock dosing helps to prevent exacerbations of pain which is easier to do than eliminate existing and escalating pain

Question 4

nociceptor pain

Answer 4

sensory nerve fibers; somatic (sharp pain localized to muscles or joints); visceral (dull, throbbing, aching pain in the internal organs)

Question 5

neuropathic pain

Answer 5

injury to nerves; burning, shooting, numbing pain that responds to adjuvant analgesics as anti seizure drugs and antidepressants

Question 6

Should someone in pain look/act like they are in pain?

Answer 6

NO! Not all pt’s report pain because they don’t want to appear weak; pt’s will sometimes sleep even when in pain; VS not always good indicators

Question 7

Gate Control Theory

Answer 7

proposes a gating mechanism for pain transmission to the spinal cord; signals from faster A-alpha and beta fibers reach spinal cord faster than slower C fibers; explain effectiveness of massage, transcutaneous electrical nerve stimulation, and possibly acupuncture in reducing pain

Question 8

4 Phases of Pain Physiology

Answer 8

1. Pain transduction (nociceptor nerve endings stimulated and chemical mediators released)
2. Pain transmission (to spinal cord)
3. Pain perception (in the brain)
4. Pain modulation (descending nerve impulses inhibit afferent pain transmission via feedback mechanism; serotonin, norepinephrine, endorphins inhibit pain transmission)

Question 9

NSAIDS

Answer 9

target peripheral NS; inhibit cyclooxygenase (enzyme responsible for formation of prostaglandin - mediator of inflammation); most adverse effects GI related; drugs of choice for mild to moderate pain, especially w/inflammation

Question 10

Acetaminophen

Answer 10

nonopioid, not classified as NSAID; MAX DOSE: 4,000mg/day

Question 11

Nonpharmacologic therapies

Answer 11

can be used instead of drugs or alongside drug therapy; allow for improved comfort, lower drug doses, and decreased potential for adverse drug effects

Question 12

Combination drugs

Answer 12

opioid and nonopioid drugs

Question 13

PCA

Answer 13

allows pt to self-administer pain meds, may reduce anxiety of waiting for meds; NURSES, FAMILY MEMBERS, OR VISITORS SHOULD NOT USE DEVICE TO GIVE PT MEDS

Question 14

Opiates

Answer 14

natural substances obtained from opium (morphine & codeine)

Question 15

Opioid

Answer 15

synthetic drug w/morphine-like activity; alter perception/emotional response to pain but not the actual pain impulses/threshold of pain

Question 16

Narcotic

Answer 16

morphine-like drug used to relieve pain

Question 17

Opioid pain management

Answer 17

usually given for moderate-severe pain; when used for long-term, can cause physical and psychological dependence

Question 18

Opioid agonists

Answer 18

activate mu and kappa receptors; relieve moderate-severe pain

Question 19

Mixed opioid agonist-antagonists

Answer 19

work on one receptor but block/have no effect on another; treat moderate pain w/less risk of respiratory depression/dependence (although still possible)

Question 20

Opioid antagonists

Answer 20

block mu and kappa receptors; treat opioid overdose (Naloxone/Narcan)

Question 21

Opioid adverse effects

Answer 21

RESPIRATORY DEPRESSION (withhold med if respirations fall below 12/min; consider Narcan if they fall below 10/min)
ORTHOSTATIC HYPOTENSION
INCREASED ICP (due to vasodilation caused by increased CO2 and respiratory depression)
URINARY RETENTION
CONSTIPATION (no tolerance usually develops)
N/V
PHYSCIAL/PSYCHOLOGICAL DEPENDENCE
TYPE 1 HYPERSENSITIVITY REACTIONS

Question 22

Equianalgesic use

Answer 22

often necessary to change route of pain med/drug itself; what drug can be given by different route/different drug while still achieving same pain relief level

Question 23

morphine sulfate

Answer 23

narcotic analgesic; opioid agonist
USE: treat severe pain, preanesthetic sedation, relieve SOB w/end-stage conditions
MOA: occupies mu and kappa receptors = altered perception of pain/emotional responses - analgesia
AE: opioid adverse effects
BLACK BOX WARNING: Schedule II controlled substance w/high potential for physical/psychological dependence
Contraindications: pregnancy; caution in older adults, undiagnosed abd pain, kidney impairment, hepatic impairment & shock; conditions w/decreased respiratory reserve
Pregnancy: avoid chronic use - can cause poor fetal growth, stillbirths, preterm births, and possible birth defects

Question 24

buprenorphine (Buprenex)

Answer 24

partial agonist at mu receptors/antagonist at kappa receptors; Schedule III drug; relieve of moderate-to-severe pain

Question 25

adjuvant analgesics

Answer 25

diverse group of drugs used to enhance analgesia for specific indications; used to supplement pain relief; pain refractory to opioids & neuropathic pain

Question 26

antidepressants

Answer 26

TCAs and SSRIs; increase levels of inhibitory neurotransmitters resulting in increased pain modulation

Question 27

anti seizure drugs

Answer 27

ex. Gabapentin; act by suppressing neuronal discharges and reducing the hyper excitability that occurs after nerve injury

Question 28

corticosteroids

Answer 28

reduce inflammatory swelling, pressure on brain, spinal cord, and spinal nevers

Question 29

local anesthetics

Answer 29

ex. Lidocaine; caution for pt’s w/heart disease or dysrhythmias

Question 30

Naloxone administration

Answer 30

1. hold opioid if respirations <12/min
2. repeat small doses of naloxone (lasts about an hour)
3. monitor to be sure drug effects outlast respiratory depression
   *naloxone reverses BOTH toxic and therapeutic effects of opioids
4. maintain patent airway
5. have resuscitation equipment ready

Question 31

migraine headache

Answer 31

throbbing, pulsating pain; preceded by aura, pt’s appear to have blood vessels that overreact to specific triggers; levels of serotonin decline, causing blood vessels to dilate/become inflamed = pain

Question 32

Goal of migraine pharmacotherapy

Answer 32

1. terminate active migraine
2. prevent/reduce frequency of migraines (most effective if begun before pain reaches severe level)

Question 33

mild migraines

Answer 33

occasional headaches w/no other functional impairment; tx: NSAIDs, acetaminophen, caffeine, triptans/ergot alkaloids

Question 34

moderate migraines

Answer 34

moderate headaches, nausea, some functional impairment; tx: oral, nasal, or SQ serotonin agonists (triptans/ergot alkaloids); can also use dopamine agonists

Question 35

severe migraines

Answer 35

severe headaches more than 3x/month, marked n/v, & functional impairment; tx: SQ, IM, or IV serotonin agonists OR dopamine agonist, narcotic analgesics for refractory pain

Question 36

Triptans

Answer 36

selective for 5-HT receptor subtype
MOA: constrict certain intracranial vessels
effective in ABORTING migraines w/or w/o auras; NOT EFFECTIVE AT PREVENTING MIGRAINES
Ex. sumatriptan (Imitrex)

Question 37

Ergot alkaloids

Answer 37

for pt’s not responsive to triptans (separate use by 24 hrs)
MOA: constrict both arteries and veins (CONTRAINDICATED IN PVD, CAD, AND SEVERE HTN)
Regular daily used can cause dependence
Pregnancy: can cause fetal harm
Ex. ergotamine (Ergostat)

Question 38

sumatriptan (Imitrex)

Answer 38

antimigraine, serotonin receptor agonist
USE: aborting active migraine attack
MOA: activates 5-HT1 serotonin receptors on intracranial and extra-cerebral blood vessels = cranial vessel constriction & reduced transmission in trigeminal pain pathways
AE: mild dizziness, nausea, diarrhea, myalgia, serious cardiac events
Contraindications: should not be used within 2 weeks of MAOIs and SSRIs; avoid use within 24 hrs of ergot alkaloids or other 5-HT1 agonists
Pregnancy: only if benefits outweigh risks
NC: administer drug at FIRST SIGN OF HEADACHE, monitor for cardiac events, and renal/liver function