Opioid Analgesics Flashcards

28 slides

1
Q

opioid analgesics purpose

A

To relieve moderate-to-severe pain.

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2
Q

endogenous opioid peptides
name the 3 families:
peptide function:

A

three families: endorphins, enkephalins, & dynorphins

  • peptides control pain and inflammation, regulate immune system, GI function, cardiovascular responses
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3
Q

Mu

A

strong agonist, high affinity with mu receptors in the CNS
–severe pain***
– possible symptoms: sedation, respiratory depression, constipation

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4
Q

strong agonist common drugs

A
  1. hydromorphone
  2. meperidine
  3. methandone **
  4. morphine **
  5. tramadol **
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5
Q

mild to moderate agonists

A
  • treat moderate pain
    common drugs:
    1. codeine
    2. hydrocodone
    3. oxycodone
    4. propoxyphene
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6
Q

mixed agonist-antagonists function

A
  • exhibit agonist and antagonist like activity at the same time
    – ex: activate kappa receptions and block or partially activate mu receptors
    -
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7
Q

mixed agonist-antagonists
strengths

A

Less risk of the side effects associated with mu receptors.

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8
Q

mixed agonist-antagonists
weaknesses

A

➢ May produce more psychotropic effects.
➢ Maximal analgesic effect may not be as great as strong mu agonists

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9
Q

antagonists
function

A

do not produce analgesia, used to treat opioid ODs and addiction

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10
Q

antagonist primary agent

A

naloxone

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11
Q

pharmacokinetics
where does metabolic inactivation take place?

A

primarily in the liver, partially in kidneys, lungs, and CNS

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12
Q

mechanism of action
name the 3

A
  1. spinal effects
  2. supraspinal [brain] effects
  3. peripheral effects
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13
Q

mechanism of function
functions

A
  1. decreased ascending (Afferent) pain transmission + activate descending (efferent) pathways that decrease pain (spinal and supraspinal effects)
  2. At peripheral sensory nerve endings, opioids decrease
    excitability of the neuron and inhibit the neuron from initiating
    transmission of painful stimuli toward the spinal cord (peripheral effects).
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14
Q

spinal effects

A

Inhibitory effect is mediated
by opioid receptors that are
located on both presynaptic
and postsynaptic membranes
of pain- mediating synapses

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15
Q

supraspinal effects

A

*goal is to decrease pain
1. opioids bind to specific receptors in the midbrain periaqueductal gray matter (PAG) and disinhibit descending pathways that decrease pain.
2. Increased activity of descending pathways travels through the ventromedial medulla (VMM) to reach the dorsal horn of the spinal cord.
3. Neurons in descending pathways release serotonin and norepinephrine onto dorsal horn synapses and inhibit the ability of these synapses to transmit
painful impulses to the brain.

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16
Q

peripheral effects

A

decreased peripheral nerve endings’ sensibility and inhibit neuron from sending pain signals to brain

17
Q

clinical applications
when are they used

A
  • acute mod to severe pain following surgery, trauma, myocardial infarction
  • chronic pain [cancer]
  • not effective in treating sharp and intermittent pain
18
Q

how are opioids administered

A
  • orally administered opioids work best when given at scheduled intervals
  • patient-controlled analgesia
19
Q

opioids side effects

A

► Mental slowing and drowsiness (sedative properties)
► Respiratory depression (slow the breathing rate)
—— Can be sever or even fatal in seriously ill patients
► Orthostatic hypotension
► GI distress
—–Nausea, vomiting, and constipation (due to its anti-peristaltic
action

20
Q

addiction

A

When an individual repeatedly ingests certain substances for mood-altering and pleasurable
experiences, such as the heroin

21
Q

tolerance

A

The need to progressively (periodically) increase the dosage of a drug to achieve a therapeutic effect (to provide adequate relief) when the drug is used for prolonged periods

22
Q

tolerance mechanisms

A

▪ Receptor down-regulation (removed by endocytosis) and desensitization.
▪ Loss of communication between the opioid receptor and the G protein.

23
Q

how long does tolerance last

A

Tolerance seems to last approximately 1 to 2 weeks after the drug is removed

24
Q

when does tolerance begin

A

Begins after the first dose of the narcotic, but the need for increased amounts of the drug usually becomes obvious after 2 to 3 weeks of administration.

25
Q

physical dependence

A

The onset of withdrawal symptoms when the drug is abruptly removed

26
Q

physical dependence

A

Withdrawal symptoms become evident within 6 to 10 hours after the last dose of the drug, and peak on day 2 or day 3 after the drug has been stopped; last about 5 days.

  • risk of addiction is low when opioids are used appropriately
27
Q

opioid-induced hyperalgesia

A

Certain patients may fail to respond to opioids or may report increased pain sensitivity (hyperalgesia)
- pain may worsen when drugs are reaching peak effect
- pain may reduce when effects are minimal

28
Q

methadone

A

Methadone
➢ Offers several advantages, such as milder withdrawal symptoms

29
Q

buprenorphine

A

An alternative; a mixed agonist– antagonist

30
Q

hyperalgesia PT implication