Alcohol Flashcards
Which is more toxic, methanol or ethanol?
methanol
Source of ethanol is…
Fermentation of sugar
3 uses of ethanol…
Beverages (wine & whisky)
Mouth wash
Hair sprays
Pharmakokinetics of ethanol…
Absorption: 80% in small intesine, 20% in stomach and large intestine
Distribution: All tissues and body fluids, can cross placenta and BBB
Metabolism: 90-98% in liver, small amount in kidney
Excretion: 2-10% excreted unchanged through breath, urine and other secretions like sweat, tears, gastric juice and bile
3 MOA of ethanol…
-CNS:Inhibits Na-K ATP in neurons which causes CNS depression
-Peripheral: vasodilation giving false sensation of heat
-Ethanol metabolism causes secrease in NAD/NADH ratio in liver causing hypoglycemia due to inhibition of gluconeogenesis, inhibits glycogen metabolism causing accumulation of fat in liver, and accumulation of lactic acid causing metabolic acidosis
Toxic dose of ethanol is…
0.7g/kg produces 100mg/dL considered legally intoxicated
300mg/dL could cause coma in novice drinker but chronic drinkers can stay awake with 500-600mg/dL or higher
3 stages of toxicity blood %…
Mild 0.05-0.15%
Moderate 0.15-0.3%
Severe >0.3%
Clinical presentation of each stage of ethanol toxicity…
-Mild (excitatory stage): euphoria, talkative, inhibition of behabioral centers
-Moderate (incoordination): drunkard (staggering) gate, slurred speech, motor skill issue, tremors of hand, hiccups due to sudden diaphragm contraction, diplopia, flushing of skin due to vasodilation
-Severe (coma & seizures):
Coma, seizures, McEwen sign (constricted pupil that becomes dilated when face/neck pinched), alcholic breath, decrease temp. Due to vasodilation and rapid weak pulse due to shock, depression of medullary centers causing respiratory depression
3 investigations for ethanol toxicity…
Rapid tests: walk in straight line, finger nose test, button unbutton test.
Chemical analysis: detect ethanol in breath, urine and blood
Blood chemistry: ketoacidosis
Cause of death in ethanol overdose…
Central asphyxia
5 treatment methods for ethanol overdose…
-Supportive: respiratory most important
-GI decontamination: gastric lavage with sodium bicarbonate and leave strong coffee in stomach. Activated charcoal useless cuz doesnt bind to ethanol
-Elimination of absorbed: forced alkaline diuresis and hemodialysis
-Antidote: no specific antidote but vit B6 accelerates ethanol metabolism by stimulation of alcohol dehydrogenase
-symptomatic: sodium bicarbonate for metabolic acidosis, hypoglycemia dextrose, hypothermia warm patient, shock fluid
Source of methanol is…
Distillation of wood
Other name of methanol is…
Wood alcohol
3 Uses of methanol include…
Aldulterate ethanol (cheap)
Household cleaning
Fuel
Pharmakokinetics of methanol…
Absorption: rapidly and completely absorbed from GIT. Inhalation and cutaneous absorption also
Distribution: same as ethanol, mainly to optic nerve
Metabolism: 90% in liver
Excretion: mainly through liver, others inckude kidney and lung