Any alcohol (hydroxylated hydrocarbon) has the potential for
toxicity. The term toxic alcohols is generally
used to refer to methanol and ethylene glycol. All alcohols cause
clinical inebriation, with the strength of the inebriating effects
directly proportional to the alcohol’s molecular weight;
hence, at the same concentration, isopropanol is more intoxicating
than ethanol (Figure 179-1).
Chemical structures of toxic alcohols.
It is useful to categorize the alcohols based on whether the
primary toxicity is due to the parent compound (ethanol and isopropanol)
or to toxic metabolites (ethylene glycol and methanol). Ethanol
and isopropanol are the most common alcohols ingested, and do not
in and of themselves cause metabolic acidosis. Their principal acute
toxicities are due to the GI irritant and intoxicating effects of
the parent compounds, and both are significantly less toxic than
methanol and ethylene glycol.
Ethanol (CH3CH2OH, molecular weight 46.07)
is a colorless, volatile liquid and is the most frequently used
and abused drug in the world. Ethanol is unique among drugs of potential
abuse because its use is legal and culturally acceptable in many
societies. Most morbidity from acute ethanol intoxication is related
to secondary injuries rather than direct toxic effects. Toxicity
most commonly results from ingestion, but ethanol may also be absorbed
via inhalation or percutaneous exposure.
Ethanol is readily available in many different forms. A standard
alcoholic beverage—such as 12 oz (355 mL) of beer (2% to
6% ethanol by volume), 5 oz (148 mL) of wine (10% to
20% ethanol by volume), or 1.5 oz (44 mL) of 80-proof spirits
(40% ethanol by volume)—contains about 15 grams of
ethanol. Ethanol may be found in high concentrations in many other common
household products such as mouthwash (may contain up to 75% ethanol
by volume) and colognes and perfumes (up to 40% to 60%) and
as a diluent or solvent for medications (concentration varies widely between
0.4% and 65.0%). Such products are often flavored
or brightly colored and may be attractive to children.
Ethanol use contributes to the number of patients seen in the
ED.1 Depending on the locale, ethanol is detected
in the blood of 15% to 40% of ED patients.2
In 2006, 32% of motor vehicle accident fatalities in
the U.S. involved an alcohol-impaired driver.3 One
quarter of the victims of interpersonal trauma report alcohol use
by their assailants, and alcohol abuse reported by the injured woman
is the strongest predictor for acute injury related to domestic
violence.4,5 From data collected in 2001 and 2002,
the lifetime prevalence of alcohol abuse and dependence in the U.S.
was estimated to be 17.8% and 12.5%, respectively.6
Ethanol is rapidly absorbed after oral administration, and blood