Substance use disorder: alcohol Flashcards
How do you calculate units of alcohol? What is the recommended weekly limit for men and women?
Units = Volume (L) * ABV (%)
e.g. a 750ml bottle of wine, strength 12% has 750/1000 *12 = 9 units
Both men and women should drink no more than 14 units a week. If you do, it is best to spread this evenly over 3 days or more.
or [Volume (mls) x Alcohol by Volume ABV (%)] / 1000
What are the effects of alcohol on the CNS?
Complex interplay between excitatory and inhibitory systems:
- Dopamine - increased in nucleus accumbens (mesolimbic system reward pathway)
- NA - inceased, enlivening effect
- Opioids - endougenous increase causing analgesia, pleasure and stress reduction
- GABA-A - anxiolytic and ataxic effects, amnesia and sedation
- Glutamate - blocking its NMDA-R, so opposing its effects and cauing amnesia and depressant effect
- Serotonin - nausea and pleasure; different levels may cause varying presentations of anxiety and aggressiveness
What are the symptoms of acute alcohol intoxication?
- slurred speech
- impaired coordination
- impaired judgement
- can lead to hypoglycaemia and coma
What are the symptoms of alcoholic ketoacidosis?
- nausea
- vomiting
- abdominal pain
- alert and lucid (unlike DKA)
Aetiology: when alcoholics miss meals or vomit then episodes of starvation lead to fat rather than carbohydrate metabolism, which generates ketone bodies.
Diagnosis: metabolic acidosis with raised anion gap due to high ketones BUT glucose nomal.
Management: IV saline + dextrose + thiamine
What is the ICD-10 criteria for dependance syndrome?
- Compulsion - strong desire to take the substance
- Control - difficulties in controlling substance-taking behaviour (onset, termination, levels)
- Withdrawal - physiological withdrawal when substance use has ceased or have been reduced
- Tolerance - increased doses required to achieve originally porduced effects by lower doses
- Salience - little alternative pleasure or interests due to psychoactive substance use, increased time needed to obtain or take the substance or to recover from its effects
- Persistance - with substance use despite clear evidence of overtly harmful consequences, such as harm to liver through excessive drinking, depressive mood states consequent to periods of heavy substance use or drug-related impairment of cognitive functioning
3 or more of the following manifestations should have occurred together for at >1 month or, if persisting for periods of <1 month, should have occurred together repeatedly within a 12-month period.
In addition to these dependence features, what else may be seen in alcohol dependence?
Narrowing of the drinking repertoire
Which drugs target GABA-A?
- Alcohol
- Z-drugs
- Benzodiazepines
- Gamma hydroxybutyrate (GHB)
- Baclofen (GABA-B)
Which are long vs short-acting benzodiazepines?
Diazepam, clonazepam, chlordiazepoxide - long acting
Midazolam, lorazepam - short acting
What is the MOA of benzodiazepines?
- Positive allosteric modulators of GABA-A
- When it binds, the receptor has greater affinity for GABA
- Increased flow of Cl- channels occyrs hence hyperpolarisation of the post-syanaptic membrane
- Hence neurone has reduced excitability
Do benzodiazepines cause tolerance or dependence?
Both
What is the stages of change model?
What questions can you ask in the history to screen for alcohol dependence?
CAGE questionnaire
- Have you tried to Cut down drinking?
- Have people Annoyed you by suggesting you do so?
- Have you felt Guilty about drinking?
- Have you needed an Eye-opener (early morning drink)?
_>_2= positive for alcohol disorders
OR FAST questionnaire (below)
Which tools can you use to assess severity and nature of alcohol misuse?
Identification:
- AUDIT (below) – alcohol use disorders identification test (>15 requires comprehensive assessment)
Severity:
- SADQ – severity of dependence
Withdrawal:
- CIWA-Ar – clinical institute withdrawal assessment of alcohol scale (for severity of withdrawal)
Social:
- APQ – alcohol problems questionnaire (assess the nature and extent of the problems arising from alcohol misuse)
What additional investigations might you do in alcohol dependence?
- Bloods: FBC, LFT, B12, folate, U&E, clotting screen, glucose
- Blood alcohol level or breathalyser
- Urine drug screen
How should you approach a consultation regarding alcohol misuse?
- Establish goals - e.g. usually abstinence
- Motivational interviewing - explore problems and encourage belief in ability to change
- Biopsychosocial approach