- A blood alcohol concentration (BAC) indicates both a level of intoxication and severity of toxicity.
- Nicotine can significantly reduce the peak BAC among newborn rodents.
- People who drink and smoke at the same time may consume more alcohol to achieve a desired level of intoxication.
- The more alcohol consumed to attain 'intoxication' in the presence of nicotine, the greater the build up of toxic agents in the system.
Mixing alcohol with other drugs - over-the-counter, prescription, legal or illegal - is a recipe for damage. The concurrent use of aspirin and alcohol, for example, leads to more severe effects on fetal brain development than the use of alcohol alone.
Heartburn medications such as Tagamet® and Zantac® slow the activity of a stomach enzyme that is responsible for breaking down alcohol, thereby leaving organ systems exposed to alcohol's toxic effects for an extended period of time. Alcohol and cocaine together exert more cardiovascular toxicity than either drug alone; they also produce a compound called cocaethylene, similar to cocaine but more lethal. Now, a study in the July issue of Alcoholism: Clinical & Experimental Research confirms the damaging interaction of alcohol and nicotine.
"Blood alcohol concentration is an important determinant for level of intoxication and severity of toxicity," explained Wei-Jung A. Chen, assistant professor of anatomy and neurobiology at The Texas A&M University System Health Science Center, and lead author of the study. "Our results confirm that blood alcohol concentration can be significantly reduced in the presence of nicotine."
In a prior study, Chen and his colleagues had found that high doses of nicotine lowered blood alcohol concentrations (BACs) among neonatal rats. In this study, they found that even low nicotine doses have an effect on BACs. In either case, the results indicate that people who drink and smoke at the same time will have to drink more if they want to feel any kind of intoxicating effect.
"In the alcohol field, we know that alcohol abusers generally 'drink to effect,'" said Susan E. Maier, research assistant professor in the department of human anatomy, College of Medicine, The Texas A&M University System Health Science Center. "This means they drink until they feel an expected level of intoxication from alcohol. It is also known that smokers drink more alcohol than non-smokers, and that people who misuse alcohol are more likely to smoke than those who do not misuse alcohol. The findings from this study suggest a possible reason why this may occur.
If nicotine lowers the BAC, more alcohol needs to be consumed in order to achieve that 'alcohol intoxicating effect.' The consumption of sufficiently more alcohol to reach that 'high' may lead to adverse effects on organ systems other than the brain, such as the liver and the heart."
The first step in the metabolism of alcohol is its conversion to acetaldehyde, which belongs to a class of compounds called aldehydes (such as formaldehyde, a disinfectant and preservative). Acetaldehyde is a highly reactive and toxic chemical that can damage the cells of all living things.
Although nicotine reduces a person's BAC, possibly leading them to drink more, nicotine does not affect the levels of agents such as acetaldehyde. The level of acetaldehyde would likely continue to build up in the system and have an adverse effect on the brain, liver and heart.
"My research primarily concerns the effects of substance abuse on the developing brain," said Chen, "so most of my studies uses newborn rat pups. This is the developmental stage that most closely represents the brain-growth equivalent of the human fetus during the third trimester. However, we have results from adult rats showing the same effects of nicotine on reducing the BAC."
Although Chen was hesitant to equate the nicotine doses used in the rodent study to human use because of the confounding effects of a number of variables (metabolism, smoking habits, smoking preferences, etc.), he did comment on what would have been considered a medium nicotine dose in the study. "There is limited information in the literature," he said, "to suggest that 1.5 mg/kg/day administered to rats may be equivalent to a human smoking one pack of cigarettes in a day."
"The best discoveries in science," said Maier, "are those that come from serendipitous findings, and I believe that the results described in this study fall into that category. What we once thought was coincidence - that smokers drink more alcohol - has suddenly gained a plausible explanation from the results of this study. Despite a plethora of studies examining the effects of each drug alone on various parameters, it is not until the interactive effects of both drugs are examined do exciting and important findings such as these reveal themselves."
Co-authors of the Alcoholism: Clinical & Experimental Research paper included Scott E. Parnell and James R. West of the Department of Human Anatomy & Medical Neurobiology in the College of Medicine at the Texas A&M University System Health Science Center, College Station. The study was funded by the National Institute of Neurological Disorders and Stroke, and the National Institute on Alcohol Abuse and Alcoholism.
Add'l Contact: Susan E. Maier, Ph.D.
The Texas A&M University System Health Science Center
Alcoholism: Clinical & Experimental Research