substance misuse - opioids Flashcards

1
Q

What opioid has the greatest dependence potential?

A

diamorphine (heroin)

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2
Q

What is an opioid/opiate?

A

natrual derivative of opium or a synthetic substance with agonist, partial agonist or mixed agonist and antagonist activity at opioid receptors

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3
Q

When does dependence develop?

A

after a period of regular use of opioids

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4
Q

What leads to opioid dependence?

A

social, psychological and biological consequences and changes in the brain

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5
Q

How soon can physical/psychological dependence develop?

A

short period of continuous use 2-10 days

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6
Q

complications of opioid dependence

A

overdose
infections eg. HIV
hepetitis
social problems - homelessness, crime

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7
Q

key elements of opioid dependence

A
  • strong desire to take opioids
  • difficulty controlling use
  • physiological wd state after reducing/stopping
  • evidence of tolerance
  • neglect of other interests
  • persistence with use despite consequences
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8
Q

What is OST (opioid substitution therapy)?

A
  • buprenorphine and methadone
    aim:
  • improve QoL of pts
  • reduce potential harm of using drugs for individual/those affected (children/family)
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9
Q

What type of drug is methadone?

A
  • mu agonist
  • weak NMDA antagonist
  • 5-HT reuptake inhibition
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10
Q

initiation and maintenance dose of methadone

A

initiation 10-30 mg/day

maintenance 60-120 mg/day

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11
Q

adverse effect of methadone > 100mg/day

A

risk of QT prolongation

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12
Q

What is the QT interval?

A

begins at onset of QRS complex and ends at end of T wave

  • time from start of ventricular depolarisation and end of ventricular repolarisation
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13
Q

ranges for QT interval

A

normal < 440ms
borderline - 440-500ms
prolonged - >500ms

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14
Q

monitoring for methadone for QT interval prolongation

A
BP
pulse
LFTs
U&E
ECG
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15
Q

signs of QT prolongation

A

palpitations
syncope (fainting)
dizziness
light headedness

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16
Q

risk factors for QT prolongation

A

> 100mg mathadone/day

QT prolonging drugs

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17
Q

What type of drug is buprenorphine?

A

partial opioid agonist at the mu receptor

antagonist at kappa receptors

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18
Q

usual and max dose of buprenorphine

A

usual 12-16mg

max 32mg

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19
Q

formulations of buprenorphine

A

sublingual tablet (temgesic unlicenced for opioid misuse)

injection

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20
Q

benefit of buprenorphine compared to methadone

A

buprenorphine less sedating than methadone

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21
Q

complications of drug misuse/presentations

A
overdose
infection (injecting)
HIV
hepatitis B/C
DVT
poor nutrition
poor dental care
psychological problems
death
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22
Q

clinical features of opioid intoxification

A
constriction of pupils
itching/scratching
sedation (slurred speech)
low BP
slower pulse
hypoventlation
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23
Q

symptoms of acute withdrawal of opioid

A
watering eyes
rhinorrhoea
yawning
sneezing
sold/clammy skin
dilated pupils
cough
abdominal cramps
N&V
diarrhoea
tremor
sleep disorder
restlessness
anxiety
ittirability
hypertension
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24
Q

What is included in a drug assessment?

A

History taking

  • degree of dependence
  • medical Hx
  • psychiatric Hx
  • family Hx
  • social problems

physical examination
- urine drug screening

investigations

  • ECG
  • LFTs, U&Es, FBC
  • screen for HIV, hepatitis B&C
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25
Q

when to do urine drug screenings

A

before OST

at least every 3mths

26
Q

How long does heroin/methadone/buprenorphine last in urine?

A

heroin up to 48hrs

methadone metabolites 7-9 days

buprenorphine 1-2 weeks

27
Q

oral fluid (mouth swab) analysis

A

if tampering wth urine samples suspected

drugs present in lower concs and shorter detection window

28
Q

2 main treatment options for addiction

A
  1. maintenance OST

2. detoxification

29
Q

What is maintenance OST?

A

used for patients who are not ready to come off opioids completely

aim - reduce/stop illicit drug use, harm reduction and stabilise lifestyle

supervised consumption for at least 3mths is maintenance decided

30
Q

What is detoxification therapy?

A

for patients who want to become drug free

aim - safe and effective discontinuation of opioids and minimal withdrawal symptoms

usually takes 28 days as inpatient, 12 weeks in community

initiated once patient stabilised on OST

31
Q

What patient use detoxification programme?

A

patients who want to stop taking opiates

32
Q

first line for detoxicifation

A

methadone or buprenorphine

33
Q

reduction of methadone for detoxification

A

reduced at a rate that will result in 0 in around 12 weeks

reduce by 5mg ever 1-2 weeks

34
Q

reduction of buprenorphine for detoxification

A

reduced by 2mg every 2 weeks

final reductions around 400mcg

35
Q

symptomatic treatment to manage withdrawal s/e

A
diarrhoea - loperamide
N&V - metoclopramide
stomach pain - mebeverine
aches/pains - paracetamol/ibuprofen
agitation/anxiety - diazepam/zopiclone
36
Q

drug used for relapse prevention

A

naltrexone

37
Q

first line opiate treatment

A

methadone

37
Q

What to consider for treatment choice?

A
  • preference for either drug
  • previous benefit from either
  • safety concerns
  • need for strong opioids other than buprenorphine for pain
  • drug interactions
  • pregnancy (both can be used)
  • risk of diversion (inc with buprenorphine)
  • severity of dependence
38
Q

risk factors for overdose in methadone induction

A
  • low opioid tolerance
  • use of CNS depressant drugs (BDZs, alcohol)
  • drug interactions
  • too high initial dose
  • too rapid dose increase
  • slow methadone clearance (hepatic impairment)
39
Q

initiation of methadone maintenance

A

week 1

  • initial dose 10-30mg/day
  • 20mg if low/uncertain tolerance/other sedative drugs
  • up to 40mg us heavily dependent
  • no more than 5-10mg inc in 1 day
  • no more than 30mg inc over 1 week

-> dose inc until confortable (60-120mg/day usually)

40
Q

When is risk for methadone overdose greatest?

A

greatest in first few weeks

41
Q

What can precipitate withdrawal syndromes with buprenorphine?

A

its partial agonist properties

42
Q

When is 1st dose of buprenorphine given?

A

when patient is exhibiting objective signs of withdrawal

ideally within 6-12hrs after last use of heroin
24-48hrs after last dose of low-dose methadone

43
Q

mild/moderate signs of withdrawal

A

anxiety
abdominal/joint pain
dilated pupils
sweating

44
Q

dose titration for buprenorophine day 1

A

day 1

  • starting dose of 4-8mg
  • withdrawal symptom dependent: mild/mod 4mg, mod/severe 8mg
  • 4mg if unknown level of dependence/high risk use of alcohol/BDZs
45
Q

initiating buprenorphine day 2

A
  • rapidy titrate dose
  • by 2/4/8mg according to response over next few days
  • aim to achieve dose that provides stable effects for 24hrs and is clinically effective
  • typical maintenance dose 12-24mg
  • max 32mg
46
Q

example of dose titration for buprenorphine

A

day 1 - up to 8mg
day 2 - up to 16mg
day 3 - up to 24mg

47
Q

Why is buprenorphine titrated qicker than methadone?

A

it is safer to initiate

less risk of over sedation respirarory depression and overdose

48
Q

Which drug has higher risk of opiate overdose?

A

methadone

49
Q

When does OD occur with methadone?

A

around day 3/4 of induction

50
Q

OD signs/symptoms

A
PINPOINT PUPILS (miosis)
RESPIRATORY DEPRESSION
UNRESPONSIVENESS/REDUCED CONSCIOUSNESS
dizziness
sedation
bradycardia
nausea
slurred speach
hypotension
coma
pale clammy skin
51
Q

How to manage opioid toxicity?

A

naloxone

52
Q

When to use buprenorphine over methadone?

A
  • safer in OD
  • adverse effects with methadone
  • pt dependent on codeine/dihydrocodeine
  • pts who want to stop heroin completely
  • less affected by interactions with enzyme inducers/inhibitors
  • better clear head/clarity of thought
  • less sedating
53
Q

When to use methadone over buprenorphine?

A
  • easier to supervise
  • better for pts using high levels of heroin
  • better in pts who continue to use
  • pts who use large amounts of heroin
  • if sedation required
  • if other opioid meds Rx
  • less supervision requiremnents
54
Q

Suboxone

A

combined sublingual tablet of buprenorphine and naloxone

4:1

55
Q

2 strenghts of Suboxone

A

2mg bup and 0.5mg naloxone

8mg bup and 2mg naloxone

56
Q

Why is sublingual Suboxone beneficial?

A

sublingually - naloxone has low bioavailability (and minimal effects) and doesn’t alter therapeutic effect of bupernorphine, reduces misuse

injected - high bioavailability which precipitates withdrawal

57
Q

When is Suboxone useful?

A

concern about pt reverting to injecting

58
Q

supervision vs take home consumption

A

supervised

  • diversion concerns
  • 1st 3 mths min
  • after treatment break
  • after significant dose inc
  • other drugs/alcohol

take home

  • stable dose
  • treatment progressing
  • no other drugs/alcohol
  • no diversion concerns
  • no mental health issues
59
Q

missed doses

A

if missed 3 days Rx treatment pt may have lost tolerance to the drug

might restart the patient with an initiation dose