Alcohol

Question 1

How do you calculate the absolute amount of alcohol?

Answer 1

%ABV x 0.78 = g alcohol/100ml

Question 2

How do you calculate the units of alcohol?

Answer 2

(%ABV x volume (ml))/1000

Question 3

Where is alcohol absorbed?

Answer 3

20% in stomach

80% in the intestines

Question 4

What effect does gastric emptying have on effects of alcohol onset?

Answer 4

Speed of onset of effects of alcohol is proportional to speed of gastric emptying

Question 5

Why is there this proportional relationship between onset of effects of alcohol and gastric emptying?

Answer 5

Alcohol is far more readily absorbed in small intestine so if you drink on a full stomach, you have a much slower rate of absorption of alcohol because the alcohol is retained in the stomach rather than going into the small intestine where it’s absorbed easily

Question 6

What percentage of alcohol is metabolised?

Answer 6

90%

Question 7

What does the breath test for alcohol measure?

Answer 7

Some of the 10% unmetabolised alcohol as it is excreted via the lungs

Question 8

Where is alcohol metabolised mainly?

Answer 8

Liver

Question 9

What enzymes are involved in the metabolism of alcohol to acetaldehyde?

Answer 9

Alcohol dehydrogenase (75%)
Mixed function oxidase (25%)

Question 10

Why isn’t metabolism finished when you form acetaldehyde?

Answer 10

Acetaldehyde is toxic so needs to be metabolised as well

Question 11

How do you develop alcohol tolerance?

Answer 11

Mixed function oxidase is induced if you continually expose yourself to alcohol so the liver becomes more effective at metabolising alcohol- this is reversible

Question 12

What limits metabolism of alcohol?

Answer 12

The liver is very good at metabolising alcohol but enzymes can be saturated

Question 13

Why are men better able to tolerate alcohol?

Answer 13

Women have about 50% body water and men have about 60% body water (in terms of fluid in the body for alcohol to be dissolved in) and women have less alcohol dehydrogenase in their stomach.
Alcohol is very water soluble so plasma alcohol concentration will be lower in the average man than woman

Question 14

How is acetaldehyde metabolised?

Answer 14

Aldehyde dehydrogenase metabolises acetaldehyde to acetic acid

Question 15

What is disulfiram used for and what does it do?

Answer 15

It is used as an alcohol aversion therapy, it blocks aldehyde dehydrogenase which leads to acetaldehyde accumulation and more negative effects of acetaldehyde will be felt

Question 16

What is asian flush?

Answer 16

Common genetic polymorphism in the aldehyde dehydrogenase enzyme which means acetaldehyde metabolism isn’t very effective

Question 17

What is the pharmacological potency of alcohol?

Answer 17

It is low- need a lot more to produce effects in body

Question 18

What is the general alcohol pharmacodynamics?

Answer 18

It is a depressant- slows down cellular activity

Question 19

What is the effect of alcohol dependent on?

Answer 19

Degree of CNS excitability at the time, environment, personality, setting

Question 20

Why is alcohol not very specific?

Answer 20

It is a simple molecule and can bind to lots of different receptors

Question 21

What are the three major CNS targets of alcohol?

Answer 21

GABA receptors
NMDA receptors
Calcium channels

Question 22

What effect does alcohol have on GABA function?

Answer 22

It enhances it so is a depressant

Question 23

How does alcohol affect chloride influx?

Answer 23

It increases allopregnenolone production which is an allosteric modulator of chloride channels and facilitates chloride channel opening hence increasing chloride influx and acting as a depressant

Question 24

What effect does alcohol have on NMDA receptor function?

Answer 24

Decreases it via some sort of allosteric modulation

Question 25

Which brain regions are particularly sensitive to alcohol?

Answer 25

Cortical regions- motor and sensory function is impaired
Corpus callous- info passing from left side of brain to right etc
Hypothalamus- appetite, emotions, temperature and pain
Reticular activating system- consciousness
Hippocampus- Memory
Cerebellum- Movement and coordination
Basal ganglia- perception of time

Question 26

How does alcohol cause flushing?

Answer 26

Vasodilation
Associated with reduced calcium entry and increased prostaglandins
Acetaldehyde is believed to be responsible for most of these vasodilation effects

Question 27

What effect does alcohol have on heart rate?

Answer 27

It leads to a centrally mediated decrease in baroreceptor which leads to reduced parasympathetic stimulation and reduced inhibition of sympathetic stimulation which causes an acute increase in heart rate

Question 28

What endocrinological effect does alcohol have?

Answer 28

It is a powerful diuretic- this effect probably is caused by acetaldehyde
It acts on neurohypophysis and inhibits vasopressin release

Question 29

What is Wernicke-Korsakoff syndrome caused by?

Answer 29

Thiamine deficiency

Question 30

Why do alcoholics develop Wernicke-Korsakoff syndrome?

Answer 30

They get a lot of their calories from alcohol so tend to have a bad diet and become thiamine deficient

Question 31

How does thiamine deficiency cause Wernicke-Korsakoff syndrome?

Answer 31

Thiamine is an important co-factor and ATP formation in cells is very dependent on thiamine but this is impaired and the Kreb’s cycle being impaired leads to oxidative stress building up in cells in the brain which causes injury and eventually apoptosis

Question 32

What is Wernicke’s encephalopathy caused by?

Answer 32

Mitochondrial injury

Question 33

What is Korsakoff’s psychosis caused by?

Answer 33

Cell apoptosis in the brain that irreversible and will probably cause the patient to die

Question 34

What is required in the liver for metabolism of alcohol to acetaldehyde?

Answer 34

NAD+

Question 35

What are the chronic effects of alcohol in the liver?

Answer 35

Build up of NADH will inhibit beta oxidation of lipids so you get fat build up in the liver that interferes with the TCA cycle so you get less ATP been produced

Question 36

What else can metabolise alcohol apart from alcohol dehydrogenase?

Answer 36

Cytochrome P450

Question 37

What is the problem with chronically using cytochrome P450 to metabolise alcohol?

Answer 37

You will generate oxygen free radicals which will contribute to damage within the cell- mitochondrial injury and inflammatory changes- this is how you get hepatitis

Question 38

How is cirrhosis caused in an alcoholic?

Answer 38

Inflammation persists that will lead to recruitment of fibroblasts which lay down connective tissue and this leads to cirrhosis and these patients may require liver transplants

Question 39

How is chronic alcohol at safe levels good for the cardiovascular system?

Answer 39

It appears to cause an increase in HDL and decrease in platelet aggregation which explains anti-atherogenic effects and reduced mortality

Question 40

What are the chronic effects of alcohol on the GI tract?

Answer 40

It is very damaging- particularly to the stomach
It can be metabolised which can lead to lots of acetaldehyde building up in the stomach and this directly damages the gastric mucosa. It is also common for chronic alcoholics to get ulcerations

Question 41

What are the chronic effects of alcohol on endocrine system?

Answer 41

Often presents with cushing’s type symptoms because alcohol causes an increase in ACTH secretion and it can also reduce testosterone secretion

Question 42

What are the symptoms of a hangover?

Answer 42

Nausea
Headache
Fatigue
Restlessness and muscle tremors
Polyuria and polydipsia

Question 43

When are a lot of the symptoms of a hangover at their worst?

Answer 43

When your blood alcohol concentration reaches zero- drinking a bit when hungover can make you feel a bit better because it increases your BAC from zero

Question 44

Why does alcohol cause nausea?

Answer 44

It irritates the stomach

Question 45

Why does alcohol cause a headache?

Answer 45

It is a profound vasoconstrictor