Alcohol intake:
(1) one standard drink = 1 ounce liquor, 1 glass wine, 12 ounces beer
(2) one drink contains approximately 10-15 grams of alcohol
(3) each gram of ethanol has approximately 7 kcal
(4) one drink raises blood alcohol level from 15-25 mg/dL
Alcohol absorption:
(1) Patients taking H2-receptor antagonists (cimetidine, ranitidine) tend to have higher blood ethanol levels for a given intake than patients not taking these agents, possibly because of inhibition of alcohol dehydrogenase in gastric mucosa.
Blood levels may be expressed in:
(1) mg/dL
(2) mg/L
(3) g/dL or weight%
(4) mmol/L
Conversion factors:
(1) from mg/dL to g/dL is division by 1000
(2) from mg/dL to mg/L involves multiplying by 10
(3) from mg/dL to mmol/L involves multiplying by 0.217
|
Blood Level in g/dL
|
Blood Level in mg/dL
|
Clinical Stage
|
|
< 0.01
|
< 10
|
negative in testing
|
|
0.01-0.05
|
10-50
|
subclinical
|
|
0.03-0.12
|
30-120
|
euphoria
|
|
0.09-0.25
|
90-250
|
excitement
|
|
0.18-0.30
|
180-300
|
confusion
|
|
0.25-0.40
|
250-400
|
stupor
|
|
0.35-0.50
|
350-500
|
coma
|
|
>=0.45
|
>= 450
|
death
|
Ethanol serum levels can be estimated from the osmolal gap (see below).
Elimination:
(1) The metabolism of alcohol is capacity-limited and can be modeled with the Michaelis-Menten equation.
(2) For simplicity, ethanol elimination is first order at low (< 20 mg/dL) and high (> 300 mg/dL) concentrations, but approximates zero order kinetics in between.
(3) When showing zero order kinetics, elimination in males average 15 mg/dL/hour and women average 18 mg/dL/hour.
(4) At high concentrations elimination is accelerated (22 mg/dL/hour at 300 mg/dL/hour).
(5) Nondrinkers tend to have lower elimination rates than daily users. Alcoholics may have high elimination rates (30 mg/dL/hour).
The serum concentration of ethanol is slightly higher than that of whole blood due to its greater water content. The ratio of serum-to-whole blood ethanol is about 1.14 to 1 (range from 1.09:1 to 1.18:1).
