Analgesia Opioids Flashcards

1
Q

What opioids are licensed for use in dos?

A

Fentanyl, methadone, pethidine, buprenorphine

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2
Q

What opioids are unlicensed?

A

Morphine

alfentanil

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3
Q

For Morphine list the duration of action, use and routes of administration

A

3-4hours
pre-medication and post-op analgesia
IV(bolus and CRI), IM, SC, epidural

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4
Q

For methadone list the duration of action, use and routes of administration

A

3-4hours
Premedication and post-op analgesia
iv(CRI bolus), IM, SC epidural

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5
Q

For pethidine list the duration of action, use and routes of administration

A

60 minutes
Pre-medication and post-op analgesia
IM, SC

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6
Q

For fentanyl list the duration of action, use and routes of administration

A

20-30minutes
intra-op and post-op
iv(bolus, CRI), transdermal

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7
Q

For buprenorphine list the duration of action, use and routes of administration

A

6 hours
premed and post-op
IV(Bolus), IM, epidural, Oral, transdermal

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8
Q

For butorphanol list the duration of action, use and routes of administration

A
60 minutes 
premed and post op analgesia and sedation 
IV (bolus), IM, SC
kappa agonist 
mu antagonist
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9
Q

What are the characteristics of an opioid?

A

Safe to give to effect

Very safe group of drugs

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10
Q

What are the clinical effects of opioids?

A

Sedation
Analgesia
Cough suppression

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11
Q

What are the undesirable effects of opioids?

A
Respiratory depression 
-when opioids administered during anaesthesia makes respiratory centre less responsive to a rise in CO2
Cardiovascular effects 
-reduction in hear rate
-dose and drug dependent
Excitation 
-rare when given im 
-don't worry about excitation in cats
Euphoria (inappropriately high doses 
Gut stasis 
Nausea and vomiting-Morphine before they are in pain
Ocular effects 
(pupillary constriction
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12
Q

How is a drop in heart rate cause be administration of an opioid managed?

A

Administration of anticholinergenic

atropine

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13
Q

What factors should you consider before administering atropine?

A

low doses iv might promote bradycardia
high doses iv can stimulate tachycardia
Try to give im
if bradycardia develops on injection IV give more atropine
If tachycardia develops on iv injection wait

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14
Q

List the opioids in order from the most analgesic efficacy to the least

A

Fentanyl
methadone
buprenorphine
butorphanol

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15
Q

List the characteristics of methadone

A

More efficacious than morphine
reduced nausea and vomiting than morphine
no concern over histamine release if given IV
Minimal CVS and respiratory side effects
licensed in cats and dogs

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16
Q

List the characteristics of pethidine

A

Very short acting
large volumes (painful on IM)
histamine release if given IV
Licensed in UK

17
Q

List the characteristics of fentanyl

A

Some respiratory depression when given during anaesthesia
induces bradycardia
useful by CRI
short acting boluses useful during surgery

18
Q

List the characteristics of Buprenorphine

A

Long acting
Good evidence to support use in cats
may not be effective via sc
delayed onset of action

19
Q

List the characteristics of butorphanol

A

Poor analgesia
Can confound subsequent full mu agonist administration
good sedation

20
Q

What premed opioid should you select for moderate to severe pain (fracture repair)

A

Methadone

21
Q

What pre-med opiod should you select for moderate pain? (ex lap)

A

Pethidine
methadone
buprenorphine

22
Q

What pre-med opioid would you select for mild pain (castration)

A

Buprenorphine

23
Q

What opioid would you select for sedation?

A

Butorphanol

24
Q

What other factors may influence the choice of opioid?

A

Use of alpha 2

Temperament of the animal (Light or heavy sedation)

25
Q

During intra-operative period what opioid would you give for severe pain?

A

Methadone
Fentanyl bolus/CRI
Epidural morphine

26
Q

During the intra-operative period what opioid would you give for moderate pain?

A

Methadone

Fentanyl bolue or CRI

27
Q

During the intra-operative period what opioid would you give for mild pain?

A

Unnecessary

28
Q

What else should you consider during the intra-operative period when administering analgesia?

A

Use of regional techniques
cardiovascular stability (greater reliance on intra-operative opiods to spare inhalant agent)
Adjunctive drugs
Alpha 2 ketamine

29
Q

How should you start analgesia in the post-operative patient?

A
Assess the patient
make a plan 
assess the patient for pain and adjust the plan accordingly 
Assess the patient for pain 
Make a new analgesia plan
30
Q

During the post-operative period what are the intervals of dosing for methadone, buprenorphine?

A

Methadone 4-5 hours
(may need extending if repeatedly administered)
Buprenorphine 6 hours

31
Q

What is the average dose for burenorphine?

A

20mcg/kg im/iv

32
Q

What is the average dosage for methadone?

A

0.3-0.5mg/kg 4 hourly intervals IV

33
Q

What is the average dose for morphine and how is it administered?

A

CRI 0.2-0.25 mg/kg/hr

34
Q

How is fentanyl administered post-operatively?

A

CRI low dose

gives better analgesia than morphine

35
Q

What is naloxone and what is it used for?

A
Reverses effect of Mu receptor opioid
Reverse opioid induced dysphoria 
Will antagonise the analgesic effect
short acting 20-30 minutes 
0.01-0.04 mg/kg iv
36
Q

What is potency?

A

The concentration of the drug required to elicit half of the maximum biological response of the agonist.
Buprenorphine is more potent than methadone or morphine

37
Q

What is efficacy?

A

The maximum biological effect that the drug or receptor ligand can achieve following binding of the drug to the receptor

38
Q

What must you consider when administering a fentanyl CRI during surgery?

A

May require ventilation of IPPV

Stop infusion 10-15 minutes before the end of the surgery

39
Q

When using a transdermal fentanyl patch what are important factors to consider?

A

Low bioavailability use another drug alongside it

take 12-18hours to be full effective