Alcohol

Question 1

1 unit of alcohol

Answer 1

10ml/8g of ethanol

Question 2

ABV

Answer 2

alcohol by volume - number of units of ethanol in a litre of fluid

Question 3

Absorption of alcohol

Answer 3

• most absorbed by simple diffusion in duodenum-jejunum

- rate of absorption is concentration dependent and related to stomach emptying (faster if drink on empty stomach)

Question 4

Distribution of alcohol

Answer 4

• ethanol distributes in water and not fat
• those with a higher fat proportion (women and elderly), alcohol has less water to distribute in –> higher concentration of ethanol in blood (greater effect)

Question 5

Metabolism of alcohol

Answer 5

1. ethanol –> acetaldehyde (alcohol dehydrogenase)
2. acetalydehyde –> acetate (acetaldehyde dehydrogenase)
3. acetate –> water + CO2
   98% metabolised this way, v small amount - P450 system

Question 6

Kinetics of metabolism of alcohol

Answer 6

• zero order kinetics - steady rate of clearance (6g/hour)

- ADH - rate limiting step

Question 7

Elimination of alcohol

Answer 7

• small amounts not metabolised but excreted unchanged in urine and breath

Question 8

Pharmacological effect of alcohol

Answer 8

CNS depressant (depression of inhibitory mechanisms in brain cause stimulatory effects)

• GABAa potentiation
• NMDA antagonist –> glutamate inhibition
• Effects on reward centres (serotonin, opiod and dopamine neurotransmission)

Question 9

Alcohol-drug interactions

Answer 9

CNS drugs –> increased drowsiness and sedation
Antihypertensive/CVS drugs –> enhanced hypotensive effect
Metronidazole/ketoconazole - inhibit ALDH
Warfarin

Question 10

Disulfiram

Answer 10

Antabuse - inhibits ALDH causing accumulation of acetaldehyde –> really bad hangover symptoms

Question 11

Medical uses of alcohol

Answer 11

• swabs/gels
• pharmaceutical solutions
• methanol/ethylene glycol poisoining - competitively inhibiting ADH

Question 12

Acute alchol intoxication

Answer 12

• can cause death by aspiration by vomiting when reduced GCS or trauma
• beware of associated hypoglycaemia

Question 13

Diagnosis of alcohol problems

Answer 13

• history - alcohol diary, screening tests (CAGE)
• examination- normally no findings but may have sigsn of CLD, parotid enlargement, rhinophyma, peripheral neuropathy
• LAB tests

Question 14

LAB tests in alcoholic

Answer 14

FBC - macrocytosis in absence of anaema
U’s & E’s - low urea
LFT’s - raised ALT/AST, raised gammaGT
INR prolongued

Question 15

Management of alcohol problems in hospital

Answer 15

• ABC - resuscitation

- prevention/treatment of encephalopathy/withdrawal/complications

Question 16

Prevention/treatment of encephalopathy (alcoholic in hospital)

Answer 16

Parental therapy - thiamine and other B vitamins

Wernickes - caused by low thiamine - eye problems, altered gait and altered mental state

Question 17

Treatment of withdrawal symptoms (alcoholic in hospital)

Answer 17

give benzodiazepines

• inhibitory effect on brain
• chlordiazepoxide or diazepam
• prescribe according to symptoms and slowly reduce dose

Question 18

Pharmacological maintenance of abstinence

Answer 18

• Acomprosate - stabilises glutamate and GABA - reduces cravings, anxiety and insomnia
• Naltrexone - opiod antagonist - reduce relapse
• Nalmefene - opiod receptor modulate - reduce alcohol consumption
• Disulfiram - antabuse - inhibits ALDH