Week 2: Opioid Agonists & Antagonists Flashcards by Ashley Campbell

Q

Opioids mimic these endogenous peptide opioid receptor ligands

A

-Endorphins (Mu)
-Dynorphins (Kappa)
-Enkephalins (Delta)

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Q

How do opioids work?

A

As an agonist on opioid receptors at pre and postsynaptic sites in the CNS

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Q

Where in the CNS do opioids work

A

Brainstem
Spinal cord

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Q

What are the 3 broad chemical structures of opiods

A

Natural
Synthetic
Semisynthetic

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Q

Substitution of methyl group for hydroxyl group on carbon 3 leads to what opiod

A

Codeine

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Q

Substitution of acetyl groups on carbons 3 and 6 leads to what semisynthetic opioid?

A

Heroin (Semisynthetic opioid)

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Q

Morphine

Natural, semisynthetic, or synthetic opioid?

A

Natural

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Q

Hydromorphone

Natural, semisynthetic, or synthetic opioid?

A

Semisynthetic

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Q

Meperidine

Natural, semisynthetic, or synthetic opioid?

A

Synthetic

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Q

Fentanyl

Natural, semisynthetic, or synthetic opioid?

A

Synthetic

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Q

Remifentanil

Natural, semisynthetic, or synthetic opioid?

A

Synthetic

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Q

Sufentanil

Natural, semisynthetic, or synthetic opioid?

A

Synthetic

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Q

Methadone

Natural, semisynthetic, or synthetic opioid?

A

Synthetic

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Q

Codeine

Natural, semisynthetic, or synthetic opioid?

A

Natural

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Q

Heroin

Natural, semisynthetic, or synthetic opioid?

A

Semisynthetic

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Q

What kind of opioids

-Contain a similar nucleus to morphine
-Pharmacodynamic differences between these drugs include potency, rate of equilibration between plasma and site of drug effect

Natural, synthetic, or semisynthetic opioids

A

Synthetic opioids

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Q

What kind of opioids result from the modification of the morphine molecule?

Natural, semisynthetic, or synthetic opioids?

A

Semisynthetic opioids

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Q

What are mu receptors principally responsible for?

A

Supraspinal analgesia
Spinal analgesia

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Q

Respiratory depression is characteristic of _____ receptor activation

(mu, kappa. delta)

A

mu

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Q

Respiratory depression less prominent with _____ receptor activation

(mu, kappa, delta)

A

Kappa

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Q

Opioids posses similar side effect profiles

True or false

A

True

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Q

Cardiovascular

Opioid side effects

A

-Bradycardia
-Decreased BP in morphine, meperidine b/c histamine
-Dose-dep. vasodilation

-Minimal effect on BP in healthy pt
-Baroreceptor reflex not affected
-Myocardial contractility not affected

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Q

Respiratory

Opioid side effects

A

-Respiratory depression
-Cough suppression

-Shifts CO2 response curve to right and reduces ventilatory response to CO2
-Decreased RR, increased Vt
-Increased PaCO2 increased ICP

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Q

CNS

Opioid side effects

A

-Sedation
-Euphora, Prolactin release (mu)
-Dysphoria, hallucinations, delirium
(kappa)
-Miosis

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GI Opioid side effects

-N+V -Decreased peristalsis/gastric emptying/constipation -Increased biliary pressure

Musculoskeletal Opioid side effects

Generalized skeletal muscle rigidity, "Chest wall" rigidity (caused by rapid administration of large doses of opioid)

Endocrine/immune Opioid side effects

-Histamine release (morphine, meperidine, codeine) -Inhibition of cellular and humoral immune function -Suppression of natural killer cell function -Decrease in cortisol -Increase prolactin, decrease luteinizing hormone, follicle-stimulating hormone, testosterone, estrogen

Cutaneous Opioid side effects

Pruritus Release of histamine = flushes skin

Body temp Opioid side effects

Hypothermia

GU Opioid side effects

Urinary retention

SSEP Opioid side effects

Minimal effects on evoked-potentials

Placental transfer Opioid side effects

Transported across placenta, can lead to depression of neonate

Opioid allergies are commonly claimed but true opioid allergies are rare True or false

True

Most opioid allergies are side effects that include what?

-Localized histamine release -Orthostatic hypotension -N+V

Opioids ________ minimum alveoli concentration (MAC) requirements of volatile anesthetics increase or decrease

decrease

What opioid is better for continuous, dull pain vs sharp intermittent pain

Morphine

Routes morphine can be administered

IV IM SC Oral Intrathecal Epidural

IV morphine causes ______ first, then ______

Sedation, analgesia

Sedation is not an indicator of pain control True or false

True

Which opioid undergoes phase 2 glucuronide conjugation in the liver to produce an active metabolite?

Morphine

The active metabolite of this opioid produces a more prolonged effect, often excessive sedation, in the renal failure patient

Morphine

Morphine produces a _________ release from tissue mast cells

Histamine

Histamine release from morphine can cause _____, _______, ______

Decreased SVR Hypotension Tachycardia

This semisynthetic opioid was derived from morphine in the 1920's and has a similar pharmacokinetic profile, but is more potent

Hydromorphone

What routes can hydromorphone be administered to

Oral Rectal Parenteral

This opioid has no active metabolites and is therefore recommended for renal failure patients, elderly

Hydromorphone

This opioid is structurally similar to atropine and has atropine-like antispasmodic effects

Meperidine

After liver demethylation, this opioid is partially metabolized to an active metabolite

Meperidine

Meperidine's active metabolite

Normeperidine

Meperidine's active metabolite, normeperidine, has ______ the analgesic effect, and its elimination half-life is _______ than meperidine

Half, longer

What does normeperidine do to the seizure theshold?

Lowers seizure threshold and induces CNS excitability

Meperidine should be used with caution in what patients?

Renal failure Cancer patients Seizure history

The most widely used opioid analgesic in anesthesia

Fentanyl

Fentanyl has a ______ (short, prolonged) duration of action

Short

Fentanyl has a profound dose dependent analgesia True or false

True

Action of a single dose of fentanyl is terminated by __________

Redistribution

Which opioid undergoes significant first-pass uptake in the lungs, with temporary accumulation before release?

Fentanyl

Fentanyl is metabolized to ________ (active or inactive) metabolites

Inactive

Regarding fentanyl, elimination is prolonged in which two patient populations

Elderly and neonate

Routes fentanyl commonly administered through

IV Intrathecal Epidural Transdermal

This opioid has a rapid onset and an ultra-short duration

Remifentanil

Remifentanil is metabolized by what?

Plasma esterases (blood and tissue esterases)

What is remifentanil's elimination half life?

8-20 minutes

Hyperalgesia is a side effect of which opioid

Remifentanil

Remifentanil is metabolized to what?

A less active compound

Remifentanil has increased respiratory depression with what drug?

Propofol

You should bolus remifentanil over 1 minute to avoid what?

Bradycardia

Which opioid is very potent, and useful when profound analgesia is needed?

Sufentanil

Sufentanil has a _______ (higher/lower) potency and ________(shorter/longer) half-life than fentanyl

Higher, shorter

Routes sufentanil can be used

IV Intrathecal

What 3 things is methadone used for primarily?

Chronic pain Opioid abstinence syndromes Heroin addiction

Methadone is well absorbed orally, and produces less euphoria True or false

True

Methadone has ______(high/low) bioavailability and ______ (an, no) active metabolites

high, no

What causes methadone to have a long half-life?

-Extensive protein binding -Lower intrinsic ability of liver to metabolize it

What can occur in methadone so that you need to be careful of repeat dosing

Accumulation

Why does it take methadone a longer time to reach steady state than other opioids

A longer half life

Which opioid does "slow on, slow off" refer to?

Methadone

In opioid Agonist-Antagonists, drugs bind to mu-receptors and produce a ____________ response

limited

In opioid Agonist-Antagonists, antagonist properties can reduce___________ of subsequently administered opioid agonists

efficacy

Side effects of opioid Agonist-Antagonists are ___________ (similar/different) to opioid agonists

similar

Advantage of opioid Agonist-Antagonists is to produce analgesia with limited depression of_____________

ventilation

Buprenorphine is what kind of opioid?

Opioid Agonist-Antagonist

Minor changes in chemical structure of opioid agonists can convert it to an opioid ____________

Antagonist

What kind of opioid is naloxone?

Opioid Antagonist

What are the 3 uses of Naloxone?

-Opiate overdose -Reversal of opiate respiratory depression -Treatment of opiate-induced pruritus

What accounts for codeine's analgesic activity?

Approximately 10% of codeine is O-demethylated to morphine

Is codeine likely to cause respiratory depression?

Not as likely to cause respiratory depression as other opioids

Morphine 10mg = ____mg codeine

120 mg

___mg of codeine is effective as antitissive

15 mg