Alcohol

Question 1

How is the absolute amount of alcohol calculated

Answer 1

% ABV x 0.78 = g alcohol/100ml (ABV = alcohol by volume)

Question 2

How are the units of alcohol calculated

Answer 2

%ABV x volume (ml) /1000

Question 3

What is the equivalent of 1 unit of alcohol

Answer 3

1 unit = 10ml or 8g of absolute alcohol

Question 4

What is the safe level for men and women (units/week)

Answer 4

less than or equal to 14 units a week

Question 5

What is binge drinking defined as

Answer 5

More than 8 units in one sitting

18% (>30%)

Question 6

Describe the dosing of alcohol

Answer 6

0.01% = 10mg/100ml blood

Question 7

What proportion of alcohol ingested is absorbed in the stomach and small intestine

Answer 7

20% absorbed in the stomach

80% in the small intestine

Question 8

How does drinking on a full stomach influence your blood alcohol level?

Answer 8

Having a full stomach causes the alcohol to remain in the stomach. This means the alcohol is unable to get to the lining of the stomach for absorption or to the small intestine where it is more effectively absorbed
Speed of onset is correlated to gastric emptying

Question 9

Describe the metabolic pharmacokinetics of alcohol

Answer 9

85% - liver
First pass hepatic metabolism

15% - GIT

Alcohol -> acetaldehyde -> acetic acid

Question 10

Which enzymes are involved in the metabolism of alcohol (and in what proportion)

Answer 10

Alcohol dehydrogenase (75%)

Mixed function oxidase (25%)

Aldehyde dehydrogenase for conversion to acetic acid

Question 11

Explain why the blood alcohol levels in the woman are likely to be higher if she drinks the same as a male

Answer 11

Women do not metabolise alcohol has effectively as they have 50% less alcohol dehydrogenase in the GIT than men

less body water (50% compared to 59%)
Less ADH

Question 12

Explain why disulfiram can be effective as alcohol aversion therapy

Answer 12

Aldehyde dehydrogenase converts acetaldehyde to acetic acid

Question 13

Describe the potency of alcohol

Answer 13

Low pharmacological potency (therefore low selectivity)

Question 14

What are the acute effects of alcohol

Answer 14

CNS
Euphoria
CVS (cutaneous vasodilation)
Diuresis/polyuria

Question 15

Explain how alcohol causes euphoria

Answer 15

1. Opiates/alcohol bind to μ - receptor
2. Reduces GABA suppression of the dopaminergic pathway
3. VATA -> NAcc
4. Dopamine release

Question 16

Which areas of the CNS does alcohol act one and what are their regular functions

Answer 16

Corpus collosum - rules, logic, impulses, feelings
Hypothalamus - appetite, emotions, temp, pain
Reticular activating system - consciousness
hippocampus - memory
Cerebellum - movements and coordination
Basal ganglia - perception of time

Question 17

Explain how alcohol causes cutaneous vasodilation

Answer 17

Reduced calcium entry, preventing pre-capillary sphincters from remaining contracted leading relaxation and blood flow through the capillaries
Increased prostaglandins

Question 18

Explain how alcohol causes an increase in BP

Answer 18

Centrally mediated decrease in baroreceptor sensitivity leads to an acute increase in heart rate and chronic alcohol may be associated with an increased blood pressure

Question 19

Explain how alcohol causes diuresis

Answer 19

Increase in ADH secretion
Reduces water excretion/increase water retention
Increases feeling of thirst

Question 20

What are the chronic effects of alcohol

Answer 20

CNS 
Liver 
CVS
GIT 
Endocrinological

Question 21

Explain the chronic CNS effects of alcohol

Answer 21

Thiamine -> enzymes in energy metabolism -> cerebral energy utilisation
Alcohol causes a thiamine deficiency -> impaired brain function
Brain regions with high metabolic demand – impaired metabolism, NMDA excitotoxicity, ROS

Question 22

What are the chronic CNS effects of alcohol

Answer 22

Dementia 
Ataxia 
Wernicke-Korsakoff syndrome 
Wernicke’s encephalopathy 
Korsakoff’s psychosis

Question 23

Explain why dementia and ataxia may be associated with alcohol

Answer 23

Dementia – Cortical atrophy/reduced volume cerebral white matter confusion (encephalopathy), oculomotor symptoms

Ataxia – Cerebellar cortex degeneration - gait

Question 24

Which areas of the brain are involved in Wernicke-Korsakoff syndrome, Wernicke’s encephalopathy and Korsakoff’s psychosis

Answer 24

Wernicke-Korsakoff syndrome - due to thiamine deficiency

Wernicke’s encephalopathy – hypothalamus/thalamus

Korsakoff’s psychosis – deep brain e.g. hippocampus

Question 25

Explain the chronic effects of alcohol on the liver

Answer 25

Alcohol requires NAD+ for metabolism, so drinking a lot uses the NAD+ stores in the liver
NAD+ required for other processes in the liver e.g. lipid metabolism (pyruvate to citric acid cycle), ETC
Impairment of liver metabolism
Fat build up
Lipid build up (lipid metabolism interfered with)
Pyruvate converted to lactic acid (acidosis) and ketones (ketosis)
Places a heavy metabolic demand on the liver

Question 26

Explain how long-term alcohol usage can lead to hepatitis

Answer 26

Blood + Hepatic cytokine changes (e.g. increased IL-6 and TNF-alpha)

Free radicals

Question 27

Explain how long-term alcohol usage can lead to liver cirrhosis

Answer 27

White blood cells and fibroblasts infiltrate the tissue and lay down connective tissue which eventually replaces the hepatocytes. Hepatocytes decrease and ability to metabolise decreases and toxins build up in the blood.
Cirrhotic liver > liver transplant

Question 28

What are the beneficial effects of alcohol on the CVS

Answer 28

Reduced mortality from coronary artery disease (Men 2-4 units/day);
Increased HDLs and tPA levels
Reduced platelet aggregation

Question 29

What are the chronic effects of alcohol on the GIT

Answer 29

Damage to gastric mucose (correlates to dose)

Carcinogenic

Question 30

What are the chronic effects of alcohol on the endocrine system

Answer 30

Increased ACTH secretion

Decreased testosterone secretion

Question 31

What are the symptoms of a hangover and explain them

Answer 31

Nausea - irritant -> vagus -> vomiting centre
Headache - vasodialtion
Fatigue - sleep deprivation
Restlessness and muscle tremors
Polyuria and polydipsia - reduced ADH secretion

Question 32

Explain why individuals may become tolerant to alcohol

Answer 32

Liver upregulation of mixed function oxidase. The same dose of alcohol will be broken down much faster by the liver.

Question 33

How does alcohol cause increased HR

Answer 33

Depression of baroreceptors which usually inhibits the sympathetic nervous system and stimulates parasympathetic. Sympathetic system becomes dominant and heart rate increases.