Module 2 - opioid analgesics Flashcards
Analgesic
A medication that relieves pain without causing loss of consciousness
Classes of Analgesics
1) opioid analgesics
2) nonsteroidal anti-inflammatory drugs (NSAIDS)
3) non-opioids
what do opioids do?
- relieve moderate to severe pain
- suppress medullary cough centre –> cough suppression (use codeine but only with non-productive coughs
- treat diarrhea (diphenoxylate/atropine (Lomotil))
where do opioids come from?
opium plant - synthetic pain reliever
types of opioids
1) Agonists
2) partial agonists (agonist-antagonist)
3) antagonist
Opioid Agonists
completely bind to opioid receptors in the brain and cause an analgesic response resulting in reduction of pain sensation
ex) morphine, fentanyl, hyrdromorphone, oxycodone, meperidine
Opioid partial agonists
bind to pain receptors but cause a weaker neurological response
ex) buprenorphine, butorphanol, nalbuphine
opioid antagonists
bind to pain receptor but does not reduce pain signal
ex) Narcan
Analgesic Ceiling effect
- occurs when a drug at a specific dosage produces a maximal analgesic effect that does not improve even if dosage is increased (dangerous, unpredictable, and has no benefit if increased further)
- associated with agonist-antagonists
opioid receptors
-5 types in body most responsive to drug therapy : opioids bind to reduce pain -µ (mu) -ƙ (kappa) -δ (delta)
opioid antidote
Naloxone (Narcan) - (antagonist)
diphenoxylate
structurally related to opioid analgesics but has no analgesic properties
opioid contradictions
-Severe asthma
-Extreme caution needed with:
respiratory insufficiency (including COPD)
elevated intracranial pressure
(ICP) (d/t increased drowsiness)
morbid obesity (sleep apnea, increased and tissue puts pressure on lungs)
myasthenia gravis
paralytic ileus (decreased bowel motility)
pregnancy
opioid allergies
rash, swelling, Angioedema (swelling of mucous membranes – mouth and eyes, throat)
Why do you have to be cautious with opioids, especially µ-receptor opioids
increased potential for psychological and physical dependence
what is the result of opioid tolerance
- Diminished drug effects over time
- Common with addiction or use for control of severe pain
µ (mu) receptors
drugs: morphine, codeine
onset: rapid and produce marked euphoria
signs of psychological dependence
impaired control over drug use, compulsive use and craving, continued use despite harm
signs of physical dependence
physiological adaption, will cause withdrawal syndrome if: abrupt cessation, rapid dose reduction, decreasing blood levels of the drug or administration of an antagonist
tolerance
the client requires higher drug dosages to reach therapeutic effects, risk of withdrawal also greater
opioid side effects
opioids release histamine thought to be responsible for side effects.
1) Flushing (redness) and orthostatic hypotension
2) CNS depression, may lead to respiratory depression
3) Sedation and euphoria
4) Nausea and vomiting
5) Urinary retention
6) Itching
7) constipation (esp c/ codeine)
treating opioid side effects
nausea (d/t gi tract irritation) - gravol
itching (d/t histamine)- benadryl
constipation (slowed peristalsis and increased absorption)- laxitives, fibre
urinary retention(increased bladder tension) - catheterization or bethanechol (a cholinergic agonist – relaxes bladder)
opioid adverse effects
RESPIRATORY DEPRESSION
monitor resps and LOC prior to administration and during.
Know antidote - narcan
how does Naloxone work to reverse opioid effects?
Will bind to opioid receptor sites and reverse respiratory depression (will also reverse pain control)
****usually only lasts about 1 hour, so if the Narcan wears off before the opioid is eliminated from the body, the respiratory depression will reappear - RE-ADMINISTER
Opioid naïve
describes patients who are receiving opioid analgesics for the first time and who therefore are not accustomed to their effects.
GIVE LOWEST DOSE
what causes additive depressant effects when administered with opioids
alcohol Antihistamines Barbiturates benzodiazepines phenothiazine other CNS depressants
Codeine
10-20 mg q4-6h when used alone When mixed with Tylenol: -Tylenol #1: 8 mg of codeine -Tylenol #2: 15 mg of codeine -Tylenol #3: 30 mg of codeine -For all above: 1-2 tablets q4-6h -Tylenol #4: 60mg of codeine (1 tablet q 4-6 h) Available as injectable, usually only used in oral form (tablets and available as syrup)
**T3 - used for moderate pain
Morphine
IV for PRN pain: 1-10 mg
SC: 1-8 mg q3h
Rectal: 10–20 mg every 4 hours (not a common route)
Oral immediate release (MS-IR): 2.5-20 mg q3h
Oral slow release (MS Contin): 15-30 mg q8-12h
Oral slow release (Kadian): 10-100 mg q24h
MS-IR
oral immediate release
MS Contin
oral slow release
Morphine MS Contin: is available in 60 mg, 100 mg and 200 mg tablets as well, higher doses usually for those who are opioid tolerant and/or with severe chronic pain (i.e. cancer patients).
Kadian
oral slow release; Once Daily dosing
NOT interchangeable with Contin
Administration routes of morphine
oral
IV
SubQ
_not often gave IM due to tissue injury and pain (histamine release)
HYDROmorphone (Dilaudid)
**7-10x stronger than morphine
Oral immediate release: 0.5-4 mg q 3h
-Up to 8 mg per dose for some patients
Oral slow release (Hydromorph Contin):
- Initially 3 mg q8-12h
- Can titrate up to 30 mg q12h
IV hydromorphone: 0.25-2 mg
SC: 0.25-2 mg q3h
oral to SC dosage formulations varies from 4:1 to 2:1
parenteral
injection meds
Fentanyl
route: IV/ transdermal patch (changed Q3D)
should not be given to opioid naive pt’s
where should transdermal patches be places?
- Patches can be applied to intact, non-irritated, dry skin on flat surface: chest, back, flank or upper arm
- Irritation or skin damage will cause more drug to be absorbed
- Fatty sites causes less to be absorbed
sites must be rotated, old patch removes, watch skin for contact dermatitis
Meperidine (Demerol)
- usually only used with morphine allergies
- long term use not recommended d/t toxin metabolite normeperidine build up
- used to treat rigours (shaking)
oxycodone (Oxy IR, OxyNEO, Percocet)
- high potential for abuse
- treat moderate to severe pain
- long-acting or time-released pain medication
- could impair judgment
Opioid Nursing Process
1) Assess: allergies, pain (intensity (0-10), character, location), LOC (sedation scale), vitals, route and time of last administered dose, kidney status, presence of head injury (med masks change in LOC)
Mornitoring When administering Dilaudid or MORPhine by the PO, PR, SC or IM route
- Baseline RR, sedation scale, and pain scale
- Check RR, sedation and pain scales at 45-60 minutes after every dose
Monitoring when administering Dilaudid or MORPhine by the IV route:
- Baseline RR, sedation scale, and pain scale
- Check RR, sedation & pain scale at 5, 15 and 30 minutes after every dose
sedation scale
s- normal sleep, easy to rouse 0- alert 1- sometimes drowsy 2- frequently drowsy, easy to rouse 3- somnolent, difficult to round
analgesic used for mild to moderate pain
nonopioids (tylenol)
NSAIDS
analgesic used for moderate to severe pain
moderate - codeine
moderate to severe pain - morphine, hydromorphone, meperidine
when do you administer opioids?
before pain becomes too severe, when pain is beginning to return.
know onset, peak, and duration
when shouldn’t opioids be administered
pt is in respiratory depression or vitals are decreased
SR
sustained release
why are opioids given with NSAIDS or Tylenol?
NSAIDS - analgesic and anti-inflammatory effects
Tylenol - synergistic effects–> coordinated or correlated action of two or more agents so that the combined action is greater than the sum of each acting separately
what do you do if opioids aren’t managing pain?
other drugs:
-corticosteroids–> antiinflammatory, antiemetic and appetite stimulation effects
-Anticonvulsants
ex)gabapentin treats neuropathic and phantom limb pain
-Tricyclic antidepressants for neuropathic pain and opioid potentiating effects
ex) Amnitriptaline (blocks receptors)
-Hydroxyzine (Atarax)
antianxiety, antihistamine and antiemetic properties, muscle spasms
Adjuvant
that which assists; esp. a drug added to a prescription to hasten or increase the action of a principal ingredient.
Equianalgesic dose
- a dose of one form of analgesic drug equivalent in pain-relieving effect to another analgesic.
- switch drugs to avoid undesired side effects from another.
- important to know to adequately control pain, nd avoid OD
immediate release and a slow release pain medication be given at the same time
relieves immediate pain as well as pain later on.
