Neuroscience Week 3: Opioid Actions Flashcards

1
Q

Understand the general pharmacokinetics of opioid compounds

A

Oral/Parenteral potency ratio

Absorption - routes of administration

Distribution - localize to highly perfused tissues

Metabolism

Excretion

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2
Q

Examples of strong opioid agonists

A
  • Morphine
  • Oxycodone (AKA oxycontine)
  • Fentanyl
  • Methadone
  • Meperidine
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3
Q

Examples of partial opioid agonists

A
  • Codeine
  • hydrocodone
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4
Q

Examples of mixed opioid agonist-antagonist actions

A

Buprenorphine

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5
Q

Other clinical uses of Opioid Analgesics:

Treating dyspnea from acute pulmonary edema

A

Morphine

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6
Q

Other clinical uses of Opioid Analgesics:

Example for antitiussive

A

Dextromethorphan

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7
Q

antitussive Definition

A

To prevent or relieve a cough

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8
Q

Other clinical uses of Opioid Analgesics:

Example for anti-diarrhea

A
  • Diphenoxylate
  • Loperamide
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9
Q

Other clinical uses of Opioid Analgesics:

Examples for shivering

A

Meperidine

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10
Q

Other clinical uses of Opioid Analgesics:

adjuncts to anesthesia

A

Fentanyl (regional)

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11
Q

Positive effects of opioids on CNS

A

Analgesia

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12
Q

Adverse effects of opioids on CNS

A
  • Mental clouding & Sedation
  • Respiratory depression
  • Antidiuresis
  • Emesis
  • Bradycardia
  • Miosis
  • constipation
  • seizures
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13
Q

Opioid antagonists

A
  • Naloxone
  • Naltrexone
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14
Q

Opioid drug interactions

A

Sedative-hypnotics - increased respiratory depression (CNS depression)

Antipsychotic tranquilizers - increased sedation and accentuates cardiovascular effects (antimuscarinic and α-blocking actions

Monoamine oxidase inhibitors - increased for hyperpyrexic coma and hypertension

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15
Q

Oral/Parenteral Potency Ratio

A

1st pass metabolism (elimination) upon oral administration

Parenteral route: elsewhere than mouth or alimentary canal; e.g. IV, IM, Sub, Q, intrathecal, etc)

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16
Q

Example of low to parenteral ratio

A

Morphine

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17
Q

Example of high oral to parenteral ratio

A

Methadone

18
Q

Codeine Absorption

A
  • reduced 1st pass metabolism, remains effectively orally
  • acts as a partial agonist at the mu receptor
  • High O/P ratio
19
Q

Oxycodone Absorption

A

moderate 1stpass metabolism, but remains effective orally Acts as a moderately strong agonist at the mu receptor. Medium O/P ratio In sustained release form:OxyContin In tablets containing acetaminophen: Percocet

In tablets containing aspirin: Percodan

20
Q

Other routes of administration

A

Nasal insufflation

of some opioids can result in rapid therapeutic blood levels by avoiding 1st pass elimination

Oral mucosa via lozenges

Transdermal via transdermal patches, which can deliver potent analgesics over many days

21
Q

Opiods are converted mostly to?

A

Opioids are converted mostly to polar metabolites (e.g. glucuronides

22
Q

How are opioids typically distributed?

A

Opioids rapidly leave the blood compartment and localize in

highest concentrations in highly perfused tissues such as:

Brain

Lungs

Liver

Kidney

Spleen

23
Q

Opioids and muscle

A

Concentrations in skeletal muscle may be lower, but muscle can

serve as a main reservoir due to its bulk

24
Q

Opiods and fatty tissue

A

Low blood flow in fatty tissue but accumulation occurs with highly lipophilic drugs in fatty tissue especially after frequent high dose delivery eg fentanyl

25
Q

Morphine Metabolism

A

Pay special attention to renal failure resulting in high circulating levels

26
Q

Fentanyl metabolism

A
27
Q

Fentanyl Absorption

A

Absorption: Highly lipophilic and slowly metabolized via transdermal route. Transdermal system: improved iontophoretic (localized electric current) allowing needle-free delivery.

28
Q

Polar metabolits such as glucoronide conjugates: M3G and H3G are excreted how?

A

In the urine

small amounts are present in the bile; a very minor amount of the excretory process

29
Q

Remifentanil Metabolism

A

bolus IV dose for a very quick procedure (cataract removal)

30
Q

Codeine is metabolized to

A

Codeine demethylated → morphine

31
Q

Hydrocodone is metabolized to

A

Hydrocodone → hydromorphone → H3G

32
Q

Oxycodone is metabolized to?

A

Oxycodone → Oxymorphone → O3G

33
Q

Codeine

hydrocodone

Oxycodone

Metabolism

A
34
Q

Poor metabolizers of codeine

A

wont experience an effect as codeine itself doesnt have strong affinity to the mu receptor

35
Q

clinical uses of opioids

A
36
Q

Mild-moderate agonist Clinical Use of Opioids

A
37
Q

Clinical uses of other opioids

A
38
Q

Opioid effects and tolerance

A
39
Q

Opioid Drug Interactions

A
40
Q

Non-opioid Therapeutics used to manage pain

A

draw attention to gabapentin and pregabalin

ketamine

tramadol however it is a weak mu opiod agonist