Alcohols Flashcards
What is an osmol gap?
- difference between the measured osmolality and the calculated osmolarity
What is osmolarity?
measure of the total number of particles in 1 litre of solution (molar concentration)
What is osmolality?
differs from osmolarity only in that the number of particles is expressed per kilo of solution (molal concentration)
What is the formula for calculating osmolarity?
2(Na) + (glucose) + (BUN)
BUN= blood urea N
What can circulating alcohol do to the serum osmolality?
- can increase the serum osmolality (alcohol and other low MW substances)
- since these substances are not included in the calculated osmolarity, there will be a gap proportional to their serum concentrations when comparing calculated vs measured values
What is the normal range for the osmol gap?
- 10 +/- 6 mOsm
How is most of ethanol eliminated?
- by enzymatic oxidation
What is the MOA of CNS depression with ethanol?
- membrane fluidification
- enhancement of GABA-nergic function
- inhibition and up regulation of NMDA receptors and increase in dopamine release
- functional tolerance (habituation)
In non-tolerant individuals, impairment of judgement can be detected at levels as low as ______
25 mg/dL
What are the s/s of acute ethanol intoxication?
- flushed face
- tachycardia
- increased sweating
- mydriasis
- muscular incoordination
- ataxia
- altered consciousness
- euphoria
- agitation
- n/v
- impaired cardiac output
- coma
- resp depression
What are some of the metabolic changes that can happen with ethanol intoxication?
- hypoglycemia
- metabolic acidosis (due to lactate and/or ketoacids)
- hypomagnesemia
What are some of the supportive care measures to give to someone with acute ethanol toxicity?
- sedatives potentially
- glucose, oxygen and thiamine
- electrolytes (Mg)
- anion gap and osmol gap
What happens with alcoholic liver disease?
- fatty liver (90% of chronic drinkers, happens when the mobilization of fatty acids and inhibition of lipoprotein synthesis)
- alcoholic hepatitis (hepatocyte degeneration and necrosis)
- alcoholic cirrhosis
Alcoholism causes enzymatic _____
induction (increases the clearance of certain drugs)
What medications does alcohol increase the clearance of?
- phenytoin
- methadone
- tolbutamide
- isoniazide
- warfarin
What causes alcohol withdrawal?
- habituation to the CNS depressant effects, uncompensated state of overstimulation (up regulation of NMDA receptors)
What can be used as treatment of an alcoholic patient?
- diagnosis
- serotonin uptake inhibitor
- naltrexone
- acamprosate calcium
- bromocriptine
- lithium
- disulfiram
- non-pharms
What is the mechanism of methanol elimination?
- zero order kinetics at high concentrations
- first order kinetics at low concentrations
- 10-20% eliminated unchanged by the lungs
- 3% unchanged in the urine
- primarily liver metabolism
Affinity of ADH for ethanol is _______ than its affinity for methanol
4x greater
The conversion of formaldehyde to formic acid is ______
very rapid (formaldehyde does not accumulate in the blood)
What is the toxic components of methanol?
methanol itself is not toxic, its metabolites formaldehyde and formic acid are the toxic metabolites
What are the effects that methanol can cause that are toxic
- direct effect on metabolic acidosis
- indirect effect (mitochondrial toxicity, binding to cytochrome oxidase, intereference with intracellular respiration, tissue hypoxia, anaerobic metabolism)
What causes ocular toxicity?
- formic acid
______ increases toxicity by favouring diffusion
acidosis
