Acute Alcohol Intoxication Flashcards
What substance is occasionally present in contaminated home brew?
Methanol
What is methanol metabolised into and by what enzyme?
Formaldehyde then formic acid.
Alcohol dehydrogenase.
What does the build up of formic acid cause and what are the complications of this?
Acidosis
Leads to blindness and/or renal failure.
What is the treatment for methanol poisoning?
Ethanol with maybe dialysis.
How does giving ethanol cure methanol poisoning?
Both metabolised by alcohol dehydrogenase leading to competitive inhibition so formic acid is not made.
What is a hallucinogenic response to alcohol withdrawal and after what medical procedure does it sometimes happen?
People see spiders.
After people come out of surgery.
Where is alcohol absorbed?
Small amount in stomach, mainly in small bowel.
Why does drinking on a full stomach make you less drunk?
Gastric emptying is slowed so more time for alcohol dehydrogenase in stomach to break down the alcohol before it is absorbed.
What drugs increase gastric emptying and what effect does this have on alcohol absorption?
Antihistamines, metoclopramide.
Increases absorption.
Why do spirits decrease gastric emptying?
They irritate gastric mucosa.
What types of drinks are absorbed faster?
Aerated drinks e.g. champagne.
What should you drink to get maximum alcohol absorption?
20-30% alcohol concentration on an empty stomach e.g. sherry.
What are the differences between men and women when it comes to alcohol?
Men have higher lean body mass (fluid component) and a higher blood volume with dilutes the water soluble alcohol.
Women have lower levels of alcohol dehydrogenase.
Describe the enzymatic pathway of alcohol metabolism.
Alcohol -> (alcohol dehydrogenase) -> acetaldehyde (gives hangover) -> (aldehyde dehyrogenase -> acetate -> CO2 and H2O.
Enzymes are in brackets.
Where does metabolism of alcohol occur in the body?
90% in liver.
Small amounts in pancreas and brain.
How is alcohol excreted?
All routes (including 5% in breath).
What rate is alcohol removed from the body?
15mg/100ml/hour (roughly 1 unit per hour).
When does alcohol concentration roughly peak and after does it decrease linearly or parabolicly?
60 mins after consumption (wide variation).
Linearly
What ethnic groups have constitutionally low levels of alcohol dehydrogenase and what ones have low levels of acetaldehyde dehydrogenase?
Alcohol dehydrogenase: aborigines, inuits, eskimos, Japanese people.
Acetaldehyde dehydrogenase: Japanese people, south east Asians,
What causes flushing in south east asians and why?
Deficient or ineffective variant of acetaldehyde dehydrogenase.
Build up of acetaldehyde is unpleasant and toxic.
Why do south east asians have low levels of alcoholism and what drugs mimic this?
Acetaldehyde build up is unpleasant, antabuse inhibits aldehyde dehydrogenase.
How does drinking tolerance develop?
Upregulation of alcohol dehydrogenase activity.
In heavy drinking alternative pathways are activated e.g. MEOS (microsomal enzyme oxidase system) involving catalase and induction of CP450.
What are the consequences for MEOS induction pathway?
Hydrogen ions are produced which must be disposed of.
What are the 3 main metabolic effects of alcohol on the body?
Krebs cycle inhibition - switch to anaerobic metabolism leading to lactic acid buildup.
Hepatic gluconeogensis inhibition - hungry and hypoglycaemia esp diabetes.
Impaired fatty acid oxidation - ketogenesis and lipid synthesis (makes you fat).
