Many medications can interact with alcohol, leading to increased risk of
illness, injury, or death. For example, it is estimated that alcohol-medication
interactions may be a factor in at least 25 percent of all emergency room
admissions (1). An unknown number of less serious interactions may go unrecognized
or unrecorded. This Alcohol Alert notes some of the most significant alcohol
medication interactions. (Although alcohol can interact with
illicit drugs as well, the term "drugs" is used here to refer exclusively
to medications, whether prescription or nonprescription.)
How Common Are Alcohol Medication Interactions?
More than 2,800 prescription drugs are available in the United States, and
physicians write 14 billion prescriptions annually; in addition, approximately
2,000 medications are available without prescription (2).
Ap proximately 70 percent of the adult population consumes alcohol at least
occasionally, and 10 percent drink daily (3). About 60 percent of men and
30 percent of women have had one or more adverse alcohol-related life events
(4). Together with the data on medication use, these statistics suggest that
some concurrent use of alcohol and medications is inevitable.
The elderly may be especially likely to mix drugs and alcohol and are at particular
risk for the adverse consequences of such combinations. Although persons age
65 and older constitute only 12 percent of the population, they consume 25
to 30 percent of all prescription medications (5) . The elderly are more likely
to suffer medication side effects compared with younger persons, and these
effects tend to be more severe with advancing age (5). Among persons age 60
or older, 10 percent of those in the community--and 40 percent of those in
nursing homes--fulfill criteria for alcohol abuse (6).
How Alcohol and Medications Interact
To exert its desired effect, a drug generally must travel through the bloodstream
to its site of action, where it produces some change in an organ or tissue.
The drug's effects then diminish as it is processed (metabolized) by enzymes
and eliminated from the body. Alcohol behaves similarly , traveling through
the bloodstream, acting upon the brain to cause intoxication, and finally
being metabolized and eliminated, principally by the liver. The extent to
which an administered dose of a drug reaches its site of action may be termed
its availability. Alcohol can influence the effectiveness of a drug by altering
its availability.
Typical alcohol medication interactions include the following (7):
First, an acute dose of alcohol (a single drink or several drinks over several
hours) may inhibit a drug's metabolism by competing with the drug for the
same set of metabolizing enzymes. This interaction prolongs and enhances the
drug's availability, potentially increasing the patient's risk of experiencing
harmful side effects from the drug. Second, in contrast, chronic (long-term)
alcohol ingestion may activate drug-metabolizing enzymes, thus decreasing
the drug's availability and diminishing its effects. After these enzymes have
been activated, they remain so even in the absence of alcohol, affecting the
metabolism of certain drugs for several weeks after cessation of drinking
(8). Thus, a recently abstinent chronic drinker may need higher doses of medications
than those required by nondrinkers to achieve therapeutic levels of certain
drugs. Third, enzymes activated by chronic alcohol consumption transform some
drugs into toxic chemicals that can damage the liver or other organs. Fourth,
alcohol can magnify the inhibitory effects of sedative and narcotic drugs
at their sites of action in the brain. To add to the complexity of these interactions,
some drugs affect the metabolism of alcohol, thus altering its potential for
intoxication and the adverse effects associated with alcohol consumption (7).
Alcohol Medication Interactions
A Commentary by
NIAAA Director Enoch Gordis, M.D.
Individuals who drink alcoholic beverages should be aware that simultaneous
use of alcohol and medications--both prescribed and over-the-counter--has
the potential to cause problems. For example, even very small doses of alcohol
probably should not be used with antihistamines and other medications with
sedative effects. Individuals who drink larger amounts of alcohol may run
into problems when commonly used medications (e.g., acetaminophen) are taken
at the same time or even shortly after drinking has stopped. Elderly individuals
should be especially careful of these potential problems due to their generally
greater reliance on multiple medications and age-related changes in physiology.
Alcohol-Medication Interactions Page Two