Pharmacotherapy of Severe Pain & Migraines Flashcards
Goal of Pain Management
reduce pain to a level that allows a pt to perform reasonable ADL’s
Key Principles of Pain Management
- pt should be considered expert of their own pain
- pain management is a pt right and should be based on pt goals
- nonpharmacologic interventions should be encouraged in addition to pharmacotherapy
- dosing should be individualized/adjusted
- adverse effects should be anticipated & PREVENTED whenever possible
Is it easier to manage pain or prevent it?
Around-the-clock dosing helps to prevent exacerbations of pain which is easier to do than eliminate existing and escalating pain
nociceptor pain
sensory nerve fibers; somatic (sharp pain localized to muscles or joints); visceral (dull, throbbing, aching pain in the internal organs)
neuropathic pain
injury to nerves; burning, shooting, numbing pain that responds to adjuvant analgesics as anti seizure drugs and antidepressants
Should someone in pain look/act like they are in pain?
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
Gate Control Theory
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
4 Phases of Pain Physiology
- Pain transduction (nociceptor nerve endings stimulated and chemical mediators released)
- Pain transmission (to spinal cord)
- Pain perception (in the brain)
- Pain modulation (descending nerve impulses inhibit afferent pain transmission via feedback mechanism; serotonin, norepinephrine, endorphins inhibit pain transmission)
NSAIDS
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
Acetaminophen
nonopioid, not classified as NSAID; MAX DOSE: 4,000mg/day
Nonpharmacologic therapies
can be used instead of drugs or alongside drug therapy; allow for improved comfort, lower drug doses, and decreased potential for adverse drug effects
Combination drugs
opioid and nonopioid drugs
PCA
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
Opiates
natural substances obtained from opium (morphine & codeine)
Opioid
synthetic drug w/morphine-like activity; alter perception/emotional response to pain but not the actual pain impulses/threshold of pain
Narcotic
morphine-like drug used to relieve pain
Opioid pain management
usually given for moderate-severe pain; when used for long-term, can cause physical and psychological dependence
Opioid agonists
activate mu and kappa receptors; relieve moderate-severe pain
Mixed opioid agonist-antagonists
work on one receptor but block/have no effect on another; treat moderate pain w/less risk of respiratory depression/dependence (although still possible)
Opioid antagonists
block mu and kappa receptors; treat opioid overdose (Naloxone/Narcan)
Opioid adverse effects
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
Equianalgesic use
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
morphine sulfate
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
buprenorphine (Buprenex)
partial agonist at mu receptors/antagonist at kappa receptors; Schedule III drug; relieve of moderate-to-severe pain
