NARCOTICS Flashcards
DESCRIBE THE DIFFERENCE BETWEEN ACUTE AND CHRONIC PAIN AND NOCICEPTIVE AND NEUROPATHIC PAIN
- ACUTE PAIN, usually cause by an injury, it’s a protective mechanism of the body that warns of potential damage, lasts from minutes to 6 months, goes away once an injury is healed
- CHRONIC PAIN, no “warning value”, lasts longer than 6 months, persists longer after trauma heals
- NOCICEPTIVE PAIN, caused by tissue injury/inflammation
- NEUROPATHIC PAIN, nerve injury, major cause of disability, responds less to drug treatment.
FACTORS THAT INFLUENCE PAIN PERCEPTION, WHICH ORGAN OF THE BODY PERCEIVES PAIN
PAIN is a subjective concept influenced by age, gender, ethnicity, usually felt like emotion and sensation.
the pain sensation is processed into the brain.
THE 2 PATHWAYS OF PAIN TRANSMISSION
- ASCENDING PATHWAY, the starting point is the site of injury, from which mediator release travels backward till the dorsal horn of the spinal substance and ascends through the spinal tract to the thalamus and projected to the sensory cortex.
- DESCENDING PATHWAY, is the brain’s response to the pain signal, from the sensory cortex down along the periaqueductal grey matter and back to the site of injury.
- the regulatory point of the nociceptive pain is the DORSAL HORN of the spinal cord, where local pro-inflammatory mediators are released back into the site of injury.
Opioids derive from ______, they contain ________ and relared compounds.
Opioid is defined as any substance producing __________ effects.
Naturally occurring opioid also called ______ are _______ and _______
synthetic opioids include pethidine, ________ and ________
poppies, morphine, morphine-like, opiate, morphine, codeine, methadone, fentanyl
opioid bind to receptors for endogenous ______ and enkephalins, they are all ______ receptors, divided by the type of subunit in ___, ____, K.
the main pharmacological actions are mediated by ___ receptors, that cause analgesia, _________, ________, reduction in GI motility, euphoria, _____, _______ dependence.
the ligand of ____ receptors stimulate mainly _____ and _______.
endorphins, g-protein, mu, delta, mu, respiratory depression, pupil constriction, sedation, physical, kappa, dysphoria, hallucination.
Opioids vary in receptor _____ and ______ at different receptors.
they can be FULL AGONIST, with a potent ______, they act mainly at ___ receptors, weak action at ___ and ___. examples are morphine, ____, ____ methadone, codeine.
MIXED AGONIST-ANTAGONIST, are agonists at ___ receptor and antagonists at ___ receptors and they can be pentazocine and nalorphine
MIXED PARTIAL AGONIST-ANTAGONIST, are partial agonists at ___ and antagonists at ____
PURE ANTAGONIST , have very little effect when given ____, they are used mainly to _____ opioid overdose because they completely ____ opioid action.
specificity, efficacy
analgesic action, mu, delta, kappa, pethidine, fentanyl
kappa, mu
alone, reverse, inhibit
MORPHINE EFFECTS ON THE CNS
- ANALGESIA, useful for acute and chronic pain, reduces the affective component of nociceptive pain, prolonged exposure might induce hyperalgesia
- EUPHORIA AND SEDATION, induce a sense of contentment, pt with chronic pain experience analgesia with no euphoria
- RESPIRATORY DEPRESSION, raises CO2 partial pressure in the bloodstream without a compensatory increase in respiratory rate, monitor closely
- SUPPRESSION OF COUGH, codeine has antitussive actions
- NAUSEA AND VOMITING, transient response to morphine, can be reduced with anti-emetics
- PUPILLARY CONSTRICTION, no tolerance to this effect, pinpoint pupils typical in overdose
MORPHINE EFFECT ON GI
- INCREASE TONE and reduced motility cause constipation
- need to be managed with therapy for constipation to avoid post-op ileo
- hypotension and bradycardia
- releases hinstamine causing itching/urticaria
MORPHINE TOLERANCE OCCURS WHEN ______ are needed to achieve the same effect.
MECHANISM OF TOLERANCE is the _______ in sensitivity of ___ receptors and adaptive changes (_______ of the receptors)
CROSS TOLERANCE can develop ____________ acting at the same receptor.
PHYSICAL DEPENDENCE characterised by ______ with ______, runny nose, ____, shivering, can be relieved with ________ like methadone, usually does’t occure at _____ doses, it rarely progresses to ______ (drug craving)
higher doses
decrease, mu, less expression
between opioids
abstinence syndrome, restlessness, diarrhoea, lomg-acting agonist, analgesic, addiction
MORPHINE PHARMACOKINETICS
- ORAL ADMINISTRATION causes slow and erratic absorption
- HIGH FIRST PASS METABOLISM
- CAN BE GIVEN I.V, I.M, S.C
- HALF-LIFE 4H
- CONVERTED TO ACTIVE METABOLITES IN THE LIVER, NARROW TI.
MORPHINE RELATED AGONISTS
- CODEINE, a weak mu receptor agonist, less potent than morphine, better antitussive agent
- DIAMORPHINE (HEROIN), mu receptors agonist, lipophilic crosses BBB, 3 times more potent than morphine, used s.c in palliative care (popular drug of abuse)
MORPHINE RELATED ANTAGONIST
- NALOXONE, an antagonist at mu, delta, and kappa receptors, has a high affinity for mu, has little effect on a drug-free person, is used to reverse respiratory depression, and responds in minutes.
- NALTREXONE, similar action to naloxone, long duration, used to treat addiction as depo/tablets.
ACUTE MORPHINE OVERDOSE, causes _____, _______ and miosis.
it’s treated with _________ or another receptor ______
danger of precipitating _______ with antagonists. Rebound oppioid stimulation
coma, respiratory depression
iv naloxone, antagonist
withdrawl
WHO STEP LADDER FOR ANALGESIC TO REDUCE RISK OF ______ not suitable for neuropatic pain only
- MILD PAIN (1-3), _______ and ______
- MODERATE PAIN (4-6), __________
- SEVERE PAIN (7-10) , strong _____, methadone, ____ or _____ administration
- ACUTE PAIN/CHRONIC PAIN WITH NO CONTROL/ ACUTE CRISES OF CHRONIC PAIN, __________________, such as nerve block, ____, _____, neurolytic block, spinal stimulators
addiction
non-opioids analgesic, NSAIDS
weak opioids
opioids, oral or transdermal
neurosurgical procedures, epidural, PCA pump.
