Flashcards in Substance Misuse Deck (61)
What is harmful use?
A pattern of use likely to cause physical or psychological damage
What is dependency?
A cluster of physiological, behavioural and cognitive symptoms in which use of a substance takes on a much higher priority than other behaviours that once had grater value
What is withdrawal?
A transient state occurring while readjusting to lower levels of the drug in the body
What is the classical conditioning theory of dependence?
Cravings become conditioned to cues
So that a cue itself can trigger a craving and thus cause drug seeking behaviour
What is the operant conditioning theory of dependence?
Behaviours rewarded are repeated: positive reinforcement
Behaviours are repeated if they relieve unpleasant experiences: negative reinforcement
What are features of dependence?
Problems controlling use
Continued use despite harm
Reinstatement following abstinence
Narrowing of the repertoire
What is tolerance?
Larger doses required to gain the same effect experienced previously
What is compulsion?
Strong desire to use the substance
What is salience?
Obtaining and using the substance becomes so important that other interests are neglected
What is narrowing the repertoire?
Loss of variation in use of the substance?
What is the social learning theory of dependence?
AKA vicarious learning
We learn by copying behaviours of others
Substance misuse can result from peer pressure
What is the neurobiological model for addiction?
All drugs if abuse affect the dopaminergic reward pathway in the brain:
Ventral tegmental area -> prefrontal cortex and lambic system
Prefrontal cortex has a role in motivation + planning
Dopamine release in nucleus accumbens= sensation of pleasure
How do cocaine and amphetamines give pleasure?
Block dopamine reuptake
= increased synaptic dopamine levels
Aetiology of alcohol misuse
Some genetic susceptibility: supported by adoption studies
Occupation: stressful work + socially sanctioned drinking
Social background: difficult childhood, poor educational achievement
Psychiatric illness: assoc with personality disorders, mania, depression, and anxiety disorders
1 unit of alcohol:
1/2 pint normal beer
Small 125ml glass wine
One measure (25ml) spirit
One measure (50ml) fortified win
Units= vol in ml x % alcohol /1000
What are safe levels of alcohol consumption?
Women: 2-3/day, 14/week
Men: 3-4/day, 21/week
What are harmful levels of alcohol consumption?
Women: >6 /day, >35 /wk
Men: >8 /day, >50 / wk
48hrs into abstinence, lasts 3-4 days
Confusion, hallucinations, affective changes, gross tremor, autonomic disturbance, delusions
Mortality rate 5% (30% with sepsis)
Management: reducing benzodiazepine regime and parenteral thiamine, management of potentially fatal dehydration and electrolyte disturbance
What is Wernicke's encephalopathy
Due to acute thiamine (vit B1) deficiency
Confusion, ataxia, opthalmoplegia
Treat with parenteral thiamine
What is korsakoff's syndrome?
Cause by untreated Wernicke's encephalopathy
Irreversible antegrade amnesia
Can register new events but cannot recall them
Patients may confabulated to fill in gaps in memory
What is intoxication?
Transient state of emotional and behavioural change following drug use, dose dependent and time limited
How would you investigate a patient with apparent alcohol misuse?
FBC: macrocytic anaemia (incr MCV) due to B12 deficiency
LFTs: gammaGT rises with recent heavy alcohol use, raised transaminases indicate hepatocellular damage
UDS: if suspect drug misuse too
Hepatitis screen: if suspect IV drug use
What can a UDS: urine drug screen detect?
Amphetamine: 2 days
Heroin: 2 days
Cocaine: 5-7 days
Methadone: 7 days
Cannabis: up to 1 month
How do you assess a patients' motivation to change?
The stages of change model:
Pre-contemplation, Contemplation, Preparation, Action, Maintenance, Relapse
Identify support needed, set realistic goals e.g.
Short term: reduce consumption
Medium term: undergo detoxification
Long term: attend college
How is detoxification managed?
Planned = following period of preparation
Unplanned = e.g. after emergency hospital admission
Long-acting benzos: prevent withdrawal symptoms incl seizures + DT
Gradually withdrawn and stopped
Thiamine: parenteral prophylaxis
What methods are used to support relapse prevention?
Psychological: CBT + group therapy
Acamprosate, anti craving drug thought to act in midbrain
Disulfiram, mimics flush reaction to alcohol making consumption highly unpleasant
How does heroin give pleasure?
A mu opiate agonist it stimulates brain and spinal cord receptors usually acted on by endogenous endorphins
How is heroin taken?
Initially often smoked
IV injection: antecubital fossa -> feet, backs of hands, groin
Veins become damaged
Subcutaneous 'skin popping' or IM
What are local complications of IVDU?
DVT: femoral injection damages valves slowing venous return
Emboli: can cause gangrene and consequently amputation
What are systemic complications of IVDU?
Septicaemia: direct injection of bacteria or from abscess/cellulitis
Infective endocarditis: tricuspid valve
Blood borne infections: hepB, hepC, HIV
Increased risk of OD less dose titration than in smoking
What are the features of opiate intoxication?
Intense rush, euphoria, warmth, well being
Bradycardia, respiratory depression
SE: constipation, anorexia, decr libido
What is the process in opiate withdrawal?
Withdrawal from IV heroin typically begins 6 hrs post injection
Peaks at 36-48 hrs, unpleasant but rarely life threatening
Dysphoria, nausea, insomnia, agitation
Diarrhoea, vomiting, lacrimation, rhinorrhoea
Feverish, abdo cramps, aching joints and muscles
Piloerection, yawning, pupil dilation
What is neonatal abstinence syndrome?
Babies born to opiate dependent mothers suffer withdrawal
High pitched cry, restlessness, tremor, loose stools, vomiting, sweats, fever, hypertonia, convulsions, tachypnoea
Treatment: paeds opiate preparations, anticonvulsants, support
What harm reduction strategies are used in the treatment of opiate users?
Sterile needle provision
Vaccination and testing for blood borne viruses
Information and advice
What is substitute prescribing?
Deliberate prescription of drugs in a controlled manner
Buprenorphine sublingual tablets
Taken in supervised environment
Doses gradually titrated to avoid withdrawal symptoms
What is naltrexone?
Opiate antagonist: mu + kappa receptors
Blocks opiate receptors and thus euphoric effects of opiates
Used as a relapse prevention agent - alcohol + opioids
Can facilitate rapid detox - opioids
What is methadone?
Full opiate agonist
Longer half life than heroin
Longer milder withdrawal
What is buprenorphine?
Partial agonist at mu receptor
Blocks euphoric effects
Prevents withdrawal sx
What is the psychoactive compound in cannabis?
Acts on cannabinoid receptors in the brain
What are the features of cannabis intoxication?
Relaxation, euphoria, paranoia, anxiety, panic
Nausea and vomiting
Injected conjunctivae, tachycardia, dry mouth
Restless and irritability after use common despite lack of withdrawal
ICD10 criteria for dependence
Narrowing of repertoire
Loss of control of drinking
Continued use despite harm
Reinstatement after abstinence
3 or more at any time
What is flumazenil
Treatment for benzo OD
How does disulfiram work?
Acetaldehyde dehydrogenase inhibitor
Unpleasant effects with alcohol:
Nausea, vomiting, flushing due to acetaldehyde build up
To help maintain abstinence
How does acamprosate work?
Blocks NMDA glutamate receptors -> enhances GABA transmission
Reduces alcohol craving
Discontinue with regular drinking!
How does chlordiazepoxide work?
Relieves alcohol withdrawal sx
Prevents withdrawal seizures
Where can patients undergo alcohol detox?
Normally in the community - give chlordiazepoxide
If hx of seizures, W-K sx, comorbid illness, suicidal ideation, lack of stable environment, prev failed outpatient detox:
When do sx of alcohol withdrawal present?
6 - 12 hrs
When do seizures present during alcohol withdrawal?
When does delerium tremens present during alcohol withdrawal?
What is delerium tremens?
Reduced GABA inhibition
Increased NMDA glutamate transmission
DON'T give phenytoin for seizures
Neuronal degeneration in the mammillary bodies secondary to thiamine deficiency
Alcoholic who become paralysed
Central pontine myelinolysis
Cocaine / opioids
Lasts 72 hrs
Nausea + vom
Aka magic mushrooms
Awkward postures, don't feel fatigue or sense of time
Loss of balance
Short lived hallucinations
Absence of sensory stimulation
Sense of detachment
Loss of appetite
MDMA aka ecstasy