Addiction, alcohol and Substance Misuse Flashcards
What is the reward pathway?
Mesolimbic pathway
What is amotivating signal?
Dopaminergic activity in mesolimbic pathway
-It incentivizes behaviour and is involved in normal pleasurable experiences
What activates mesolimbic pathway?
All drugs of abuse, therefore person can develop a want to seek these drugs continually
Concept of tolerance?
Repeated exposure to drug leads to down regulation of dopamine receptors meaning more is needed to get same response
What ‘puts brakes on’ mesolimbic pathway?
Prefrontal cortex, however it is not fully mature until 20s so is vulnerable whilst person is developing
What is dysfunctional in addicted people?
Prefrontal cortex
What other structures are implicated in development of addiction?
Hippocampus
Amygdala
Explain how stress plays a role in addiction?
Chronic stress leads to dampening of dopaminergic activity through the down regulation of D receptors, which reduces sensitivity to normal rewards encouraging exposure to highly rewarding behaviours
Criteria for dependance?
- 3 or for at least 1 month:
- Sense of compulsion
- Craving
- Physiological withdrawal
- Preoccupation with substance use
- Persistent use despite harmful consequences
What can criteria for dependence be used for?
Any addiction
What is hazardous drinking?
-Pattern of alcohol consumption that increases the harmful consequences for user
What is hazardous drinking defined as in women?
> 14 units but <35 units a week
What is hazardous drinking defined as in men?
> 14 units but <50 units a week
What is harmful drinking?
Pattern of alcohol consumption that is causing mental or physical damage
What is harmful drinking defined as in women?
> 35 units a week
Harmful drinking in men defined as?
> 50 units a week
Criteria for alcohol withdrawal?
Any 3 of:
- Tremor of outstretched hands, tongue or eyelids
- Sweating
- Nausea, retching or vomiting
- Tachycardia/HT
- Anxiety
- Psychomotor agitation
- Headache
- Insomnia
- Malaise or weakness
- Transient visual, tactile or auditory hallucinations or illusions
- Generalized tonic clonic seizures
What is delirium tremens?
-Most serious withdrawal state- medical emergency
When does delirium tremens occur?
1-3 days after alcohol cessation
Presentation of delirium tremens/
- Disorientation
- Agitated
- Marked tremor
- Tactile visual hallucinations (insects etc)
Signs of delirium tremens?
- Sweating
- Tachycardia
- Tachypnoea
- Pyrexia
How can delirium tremens be treated?
- Correct dehydration
- Electrolyte abnormalities and thiamine replacement
- Give chlordiazepoxide
What does chlordiazepoxide help with?
Withdrawal
What is included in Wernicke Korsakoff Syndrome?
Wernicke’s encephalopathy
Korsakoff syndrome
What are WE and KS bothe due to?
Thiamine deficiency
What causes Wernicke’s encephalopathy?
Acute thiamine deficiency
What does acute thiamine deficiency result in?
Cytotoxic oedema in mamillary bodies
Signs/symptoms of Wernicke’s encephalopathy?
Ocular dysfunction
Ataxic gait
Acute confusion
Prevent progression of Wernicke’s syndrome to what and by doing what?
To Korsakoff’s
By thiamine replacement and early recognition
What is Korsakoff’s due to
Chronic thiamine deficiency
What is there in Korsakoff’s?
Cerebral atrophy
How does Korsakoff’s present?
Profound anterograde and retrograde amnesia
- Confabulation to fill in memory gaps
- Generally lacks insight
Key treatment for Korsakoff’s?
Abstinence and nutrition but generally chances of recovery are low
Diagnostic markers of alcohol misuse in recent weeks?
- Elevated GGT
- Elevated mean corpuscular volume
Managemnet of alcohol withdrawal?
- Reassure
- Long acting Benzos alleviate symptoms
- Vitamin supplementation
- Thiamine prophylactically
Why are long acting benzos used in alcohol withdrawal?
To help alleviate symptoms
-They are cross tolerant with alcohol due to action on GABA receptors, usually chlorodiazepoxide is used
What happens to dose of chlordiazepide over 7 days?
Reduced
Relapse prevention for alcohol dependence syndrome?
- CBT
- Motivational enhancement therapy
- 12 step facilitation therapy
- Behavioural self control therapy
- Family and couple therapy
Benzos and alcohol dependence syndrome?
-No place for benzos post detox
1st line pharmacological treatment for alcohol dependence syndrome?
Naltrexone:
-Opioid antagonist that reduces reward for alcohol
Other pharmacological treatments for alcohol dependence?
- Acomprosate reduces cravings
- Disulfiram inhibits alcohol dehydrogenase leading to accumulation of acetaldehyde
Side effects of disulfiram?
If alcohol is ingested it causes flushed skin, tachycardia, N&V, arrhythmias and hypotension
Pharmacological management of opioid use?
Naloxene
-Methadone or buprenorphine: heroin substitute for withdrawal
Why are methadone and buprenorphine good?
Methadone: orally
Buprenorphine: sublingual
Therefore less risk of non-sterile needles and also because taken once daily there are less peaks in opioid levels
Tools used for alcohol screening?
FAST
AUDIT (Alcohol use ID test)
CAGE (Screens for dependence)
Physiology of alcohol?
Alcohol inhibits action of excitatory NMDA glutamate controlled ion channels
-Alcohol potentiates actions of inhibitory GABA type A controlled ion channels
Usual onset of delirium tremens?
Insidious with night time confusion
Dopamine release effects?
- Ability to update information within prefrontal cortex
- Ability to select new goals
- Ability to avoid compulsive repetition behaviour
Who gets addiction?
About 50% is heritable
Most common opioid?
Heroin (brown powder)
What are natural opioids?
Morphine
Cocaine
Natural from opium poppy
Semi synthetic opioids?
Hydrocodone
Hydromorphone
Fully synthetic opioids?
Methadone
Tramadol
Indications for when buprenorphine should be taken?
In front of community pharmacist
