Module 8: Alcohols, Glycols Flashcards
Methanol, Ethanol, and Isopropanol are all alcohols by their structure; acetone is really a _____ by its structure
ketone
What is present in grey top blood tubes?
1 % Sodium Fluoride (preservative) potassium oxalate (anti-coagulant)
Type of elimination that Ethanol falls under
Zero-Order Elimination
-Constant amount eliminated per unit time
-Switches to first-order at smaller concentrations
0.015 - 0.020 g/100 mL/hr
Where most EtOH is absorbed
Small Intestine
How long does it take for most alcohol to be absorbed?
1 hour
Approximate conversion for Serum to Blood EtOH concentration
1.2
Volume of Distribution of EtOH for Men vs. Women
men = 0.68 L/kg
women = 0.55 L/kg
True or False:
If doing a retrograde extrapolation must question if person is in absorption or elimination phase
True
-If person is still absorbing, the [EtOH] will be greater at time of blood sampling compared to actual OVI
What is Henry’s Law?
relationship between concentration of dissolved gasses in a liquid to the concentration of the air above the liquid; concentration in lungs directly related to that in blood
BAC : BrAC
2300:1
(shown as 2100:1 in these quizzes…)
How is EtOH metabolized and eliminated by the body?
2-5% breath, urine, sweat
~0.1% Ethyl Glucuronide and Ethyl Sulfide
95% Oxidative metabolism via ADH
Explain Oxidative Metabolism of EtOH.
3 ways:
1) EtOH + ADH –> Acetaldehyde; Acetaldehyde + ALDH –> Acetate
involves reducing NAD+ to NADH
2) Catalase
3) CYP2E1
Where can alcohol dehydrogenase be found?
In cytosol of cells in liver and stomach
Microsomal ethanol oxidizing system (MEOS)
CYP2E1
Found in microsomal fraction of liver hepatocytes
This is inducible is a person is a chronic ethanol user
CYP2E1 Microsomal Ethanol Oxidizing System
This means alcoholics can concert ethanol faster; have faster elimination rates
Accumulate of acetaldehyde is influenced by what four enzymes?
ADH, catalase, CYP2E1, ALDH
2 Ethanol Biomarkers
Ethyl Glucuronide and Ethyl Sulfide
What is ALDH?
Enzyme that converts Aldehyde to Acetate (in Ethanol metabolism)
allele variation present in East Asians (~45%)
ALDH allele variation; means inactive ALDH2 enzymes
Specimen to Blood Concentrations in post absorptive stage
Saliva, Spinal Fluid
Vitreous
Bile
Liver
Kidney
Brain
Urine
Saliva, Spinal Fluid 1.1
Vitreous 1.2
Bile 1.0
Liver 0.6
Kidney 0.7
Brain 0.8
Urine 1.3
Think: organs are slightly less; rest are slightly more
Serum = 1.2, Urine =1.3/1.4
3 Types of Glycols
Ethylene Glycol (antifreeze, solvent)
Propylene Glycol (preservative, emollient in medications)
Diethylene Glycol (car things, solvent)
Metabolic Pathway of Ethylene Glycol
Ethylene Glycol + ADH –> Glycoaldehyde
Glycoaldehyde + ALDH –> Glycolic Acid
(Glycolic Acid +GADH –> Glyoxazlic Acid)
(Glyoxalic Acid + GADH –> Oxalic Acid)
Oxalic Acid + Ca2+ –> Calcium Oxalate
Stages of Toxicity for Ethylene Glycol
1) Neurological (appears innebriated, nausea, coma, convulsions)
2) Cardiopulmonary (tachypnea, tachycardia, hypertention, CHF, pulmonary edema)
3) Renal (flank pain, tubular necrosis)
Treatment for Ethylene Glycol Poisoning
-Ethanol! It competes for ADH
-Enzyme will be busy metabolizing EtOH and Ethylene Glycol can’t break down into toxic metabolites
-Person can then undergo hemodialysis to clear Ethylene Glycol
Methanol is primarily metabolized via alcohol dehydrogenase to:
Production of formaldehyde
(Methanol –>Formaldehyde –> Formic Acid)
Significant hypocalcemia can occur with:
Ethanol toxicity
Acetone toxicity
Ethylene glycol toxicity
Methanol toxicity
Isopropanol toxicity
Ethylene glycol toxicity
Hypocalcemia means not enough; think about the pathway and formation of calcium oxalate
Antidote for ethylene glycol poisoning:
Fomepizole
These crystals are associated with ethylene glycol poisoning:
Calcium Oxalate
The fermentation of glucose in blood to produce ethanol can be prevented by:
Sodium Fluoride (1%)
Metabolite of Isopropanol
Acetone
Methanol, Ethanol and Isopropanol. Rank in order from most toxic to least toxic:
Methanol, Isopropanol, Ethanol
Ethylene glycol is metabolized by alcohol dehydrogenase to:
Glycoaldehyde
A person experiencing ethylene glycol toxicity may show:
Deep and rapid breathing
Shallow and rapid breathing
Deep and slow breathing
Shallow and slow breathing
Deep and rapid breathing
This substance is sometimes present in chronic alcoholics and malnourished individuals: Acetone
Acetone
Fatal poisoning due to methanol is usually a result of:
Production of formic acid
In the absorption phase, the blood alcohol concentration is 52 mg/dL. The vitreous alcohol concentration is expected to be ________ as compared to the blood alcohol concentration.
Lower, higher, or equivalent
Lower
*pay attention to absorption vs post absorption
