July 25, 2006
HEALTH: Tobacco Could Boost Urge to Drink Alcohol
By Lee Bowman
Scripps Howard News Service
Those cigarettes may be driving you to drink more.
A new study done on rats shows that nicotine can actually reduce blood
alcohol concentrations and thus lead to heavier drinking.
"Since the desired effect of alcohol is significantly diminished by
nicotine, particularly among heavy or binge drinkers such as college
students, this may encourage drinkers to drink more to achieve the
pleasurable or desired effect," said Wei-Jung Chen, an associate professor
of neuroscience and experimental therapies at the Texas A&M Health Science
Center in College Station, Texas, and lead author of the study, published in
the August issue of the journal Alcoholism: Clinical & Experimental
Research.
The notion that there's cross tolerance for certain drugs -- where a
decrease in the reward from one drug seems to facilitate the use of another
to achieve the same effects -- has been debated for more than 50 years.
But only two previous studies have looked at the interactions between
nicotine and alcohol, so that little is known about how nicotine influences
the metabolizing of alcohol, said Scott Parnell, the latest report's
co-author and a postdoctoral research fellow at the University of North
Carolina.
For the new study, Chen and Parnell and colleagues administered a range of
nicotine doses adjusted for body weight along with an alcohol dose delivered
either directly into the stomachs or the abdominal cavities of female rats.
The blood alcohol content was measured against the nicotine doses as various
times.
Chen said it was clear that the presence of nicotine significantly reduced
peak blood alcohol content, but this was only observed when the booze went
into the stomach, not when it was injected into the abdomen.
"In humans, this means that persons desiring to drink to effect will need to
drink more alcohol while smoking in order to reach this effect, and this
will lead to increased amounts and lingering presence of toxic byproducts of
alcohol metabolism," said Susan Maier, a health scientist administrator at
the National Institutes of Health, which sponsored the study.
Moreover, she said, cross tolerance can lead to permanent changes in the
physiology of metabolism, so that beneficial drugs may not be as
well-absorbed in some people who both smoke and drink alcohol.
Likewise, the fact that nicotine only interferes with the processing of
alcohol when ingested is important. "Nicotine appears to delay the emptying
of the stomach contents, including alcohol, into the intestines. A portion
of the alcohol molecules are subject to metabolism within the stomach,
leaving less alcohol passing from the stomach to the intestinal tract for
absorption," and putting less alcohol into the bloodstream, Chen said.
"These findings ... highlight the effects of polydrug interactions, which
has implications for the effects of other drugs, not necessarily illicit
drugs, that may be co-used with alcohol, such as aspirin," Maier added.
"These results suggest, but do not directly test, the hypothesis that other
drugs that modify specific stomach functions, such as the active ingredients
of (anti-heartburn drugs) Pepcid, Zantac and Tagamet, may also alter alcohol
metabolism when consumed simultaneously."
Chen plans further research aimed at understanding the interactive effects
of abused substances, particularly on the development of the adolescent and
young adult brain.
On the Net: http://www.nih.gov
www.medicine.tamhsc.edu/
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