Absorption, Distribution, and Elimination of Alcohol

AuthorJames G. Wigmore
Absorption, Distribution, and Elimination
of Alcohol
The absorption, distribution, and elimination of alcohol, the focus of
this chapter, are also known as the pharmacokinetics of alcohol. Phar-
macokinetics is basical ly the study of what the body does to a drug: how
the drug is absorbed, dis tributed, and metabolized by the various organs
of the body. Although the pharmacokinetics of alcohol has been d ivided
into the separate topics of absorption, distribution, and elimination, it
should be emphasized that these processes occur nea rly simultaneously
in the body.
When the absorption of alcohol is greater than the elimination, the
blood alcohol concentration (BAC) increases. When absorption is slowed
down, such as with the ingestion of food, and absorpt ion is equal to elimin-
ation, a plateau occurs in which the BAC apparently does not change. When
absorption is less than elimi nation, a decrease in the BAC occurs that is
basically linea r until all the alcohol has been eliminated f rom the body.
Absorption > Elimination → BAC Increases
Absorption = Elimination → BAC Plateaus
Absorption < Elimination → BAC Decreases
If there is rapid absorption of alcohol from quick oral drink ing or
intravenous infusion, then distribution may lag behind absorption and
result in a signif‌icantly higher alcohol concentration in the arterial
blood than the venous blood (arteriovenous [AV] lag).
The typical drinking patter ns and pharmacokinetics of drinking
drivers are also discussed in this chapter, as well as the extrapolation
or back calculations of the BAC of the drink ing driver to an earlier time.
Wigmore on Alcohol
Reference Number: 
Widmark (or forward) BAC calculations, which are generally much less
reliable than back calcu lations, are presented in section .. The ef‌fects
of other drugs (e.g., cimetidine) and of trauma are covered in sections
. and ., respectively.
Alcohol is generally absorbed after oral consumption via the stomach
and small intestine. Alcohol is a unique drug in that it can be substan-
tially absorbed via t he stomach (–), although absorption through
the small intestine is faster. The concentration of alcohol in the stom-
ach decreases rapidly, so it is rarely benef‌icial to lavage or remove the
contents of the stomach in alcohol-intoxicated patients as usually only
minimal a mounts of alcohol remain in the stomach by the time the pa-
tient presents to hospital ().
Food ingestion tends to slow the absorption of alcohol and decrease
the maximum BAC, but it does not substantia lly prolong the time to
peak BAC (–). Carbonation tends to cause a more rapid absorp-
tion of alcohol and increase the initial BAC (, ), but salty
foods and warm temperatures of alcoholic beverages do not signif‌icant-
ly change the rate of alcohol absorption (, ). Various gastric
surgeries such as a gastric bypass may substantially increase the rate of
alcohol absorption, and patients who undergo these operations should
be warned of this ef‌fect ().
Alcohol is not signif‌icantly absorbed by inha lation through the lungs
(–) or via dif‌fusion th rough the skin (, , , ).
Hence, frequent use of an alcohol-based hand sanitizer does not result
in a signif‌icant BAC (, ). Alcohol can be rapidly absorbed by
intravenous infusion (, ) or by rectal enema ().
Reference Number: 
, ..,  . . “The Absorption of Ethyl Alcohol from
the Gastro-Intestinal Tract as a Dif‌fusion Process.” Acta Physiologica
Scandinavia, /: –, / ( tables,  f‌igures,  references)
Abstract: The absorption of alcohol from the stomach was determined
in cats and humans. Several human subjects were admi nistered up to
 mL of a % or % alcohol solution via a stomach tube. The stomach
alcohol concentration was then determined over time. A mathematical
Absorption, Distribution, and Elimination of Alcohol
Reference Number: 
model (based on Fick’s law) of the dif‌fusion process was presented. In
human subjects with a closed pylorus, approximately % of the alcohol
was absorbed after  minutes, % after  minutes, a nd % after 
minutes. If the stomach was empty, % of the alcohol was able to be
absorbed within  minutes. Tests were also conducted on patients with
gastritis and ach lorhydria (associated with severe anemias a nd stomach
cancer), and no signif‌icant dif‌ferences in alcohol absorption from the
stomach were observed compared with that in normal s ubjects.
Table. Percent of Alcohol Absorbed from the Stomach and
Stomach Emptying Time in Five Normal Subjects after
Instillation of  mL of % Alcohol Solution
Percent Alcohol Absor bed from
Time of Stomach Emptyin g
Subject No.  min  min
  
  
  
 
  
 = not available.
Source: Adapted from Berggren an d Goldberg (/).
The absorption of ethyl alcohol from the stomach follows the laws of
dif‌fusion. This means that the greater the concentration of alcohol in -
gested, the more rapidly absorption will t ake place with a higher and
earlier blood alcohol maximum.
Reference Number: 
, .. “The Simultaneous Emptying and Absorption of Ethanol from
the Human Stomach.” Digestive Diseases, : –,  ( tables, 
f‌igures,  references)
Abstract: A total of  meals ( of water and  of .% volume of sol-
ute per volume of solvent [v/v] ethanol) were given to seven healthy, fast-
ing subjects. The volume of the meals was  mL . Gastric contents were
aspirated at various times, a nd the alcohol concentration was measured
by an alcohol dehydrogenase (ADH) procedure. The emptying of ethanol
meals and water meals proceeded at the same rate up to about  min-
utes, when about % of the meal had left the stomach. The absorption

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