Alcohol Statistics
Alcohol is the most abused drug globally, with about 2 billion people consuming it. Over 76 million people have alcohol use disorder because the drug is socially acceptable (Centers for Disease Control, 2019). Whether driving down a road, watching a movie, sitting on the couch, or enjoying a weekend out, people are seen with alcohol. Alcohol kills over 95,000 Americans each year due to diseases related to the drug or situate ions that occur under the influence of Alcohol, such as accidents in drunk driving (Centers for Disease Control, 2019). Despite the number of people with alcohol disorders in the US going to over 15 million, only 8% seek medical treatment (Centers for Disease Control, 2019). This shows that many people have not accepted that they are addicted to the drug and need medical help, so it is important to create awareness of alcohol and substance abuse.
Pharmacology of Alcohol Absorption
Alcohol contains ethanol, the product that gets individuals drunk. Therefore, the more ethanol in a person’s blood, the drunker they are likely to be. 20% of the ethanol consumed is absorbed in the stomach, while the remaining 80% is absorbed in the small intestines (Biddinger et al., 2022). However, the absorption rate may vary depending on the factors stated above.
Distribution
When ethanol is absorbed into the body, it goes to the liver, then uses the hepatic vein to get to the heart before going to the lungs. From the lungs, it is pumped again back to the heart and distributed to other body parts, including the entire systemic circulation system (Biddinger et al., 2022). The ethanol creates an equilibrium with the blood, but it depends on several issues, such as the cross-sectional area of the fluid and other body organs. Organs with a large cross-sectional area and those with a high blood flow rate, such as kidneys, brain, and liver, take a shorter time to equilibrate.
Metabolism
The metabolism of Alcohol is conducted in the liver using various enzymes and biochemical processes. This leads to energy production, unlike other psychoactive drugs in the body. The main metabolizing enzyme is called dehydrogenase, found in the cytosol fraction of the liver cells. This enzyme converts ethanol to acetaldehyde, a more toxic product than the main drug taken. However, it is oxidized by km ALDH which is found in the mitochondria, as shown in figure 1 (Jones, 2019). During this process, the other co-enzyme nicotinamide adenine dinucleotide is changed to NADH, leading to a rise in NADH/NAD+ hepatocytes.
Excretion
The excretion process is primarily conducted using oxidation, whereby metabolism occurs in the body. However, some portion is still excreted through the body organs, such as kidneys, lungs, and skin. This is why after a person has taken Alcohol, it can be recovered using urine, breath, or skin analysis. These tests are used to prove that person has consumed Alcohol; however, they are only effective for a short period. For instance, if a urine sample is collected within seven hours of moderate drinking, it can prove that a person has consumed Alcohol. Sometimes the urinary BAC may go up to 120mg% (Jones, 2019). This implies that the dose excreted should reach a higher BAC in first-order urinary excretion.
Biotransformation of Alcohol
ADH metabolizes ethanol into a very toxic substance called acetaldehyde which stays in the body for a few hours. Acetaldehyde is metabolized to carbon and water; however, if a person has consumed high amounts of Alcohol, the enzyme cytochrome P450 2E1 (CYP2E1) helps in the metabolic process (Zhao et al., 2021). Acetaldehyde affects the parts where ethanol metabolism occurs, including the liver. In addition, it can cause damage to brain cells, the pancreas, and the gastrointestinal tract due to the metabolism process. Acetaldehyde has been found to have behavioral and psychological effects on an individual, which include impaired judgment, incoordination, and sleepiness.
Effective Alcohol Dose
The first step to ensure effective drinking for a person is to ensure that they have reached the legal drinking age. This ensures that they are sound-mind and can make their drinking decisions independently with less influence. Generally, it is acceptable for men to take two drinks a day or less, while for women, it is only one drink. However, scientific proof has it that each drink should be taken in different volumes depending on its alcohol percentage. For beer, a person should consume 12 ounces; for malt liquor, it is 8 ounces; wine is 5 ounces, while hard liquor is 1.5 ounces (Centers for Disease Control, 2019).
Lethal Alcohol Dose
When a person is drunk, their BAC increases depending on how much they have drunk. According to studies, the more the BAC, the more lethal the risks. A BAC of 0.08 shows that a person has consumed a slightly higher amount of Alcohol and is likely to have signs such as impaired judgment, nausea, and confusion (Centers for Disease Control, 2019). However, when alcohol levels go over 0.40, this is a sign of a lethal dose, and it can kill (Centers for Disease Control, 2019). During this state, a person can start to have seizures, slow heart rate, clammy skin, irregular breathing, vomiting, and mental confusion. Figure 2 shows how an individual is likely to react at different stages of thinking. The more the CAB rises, the more risky the effects are, showing that drinking above 0.45 BAC can lead to death.
Impact of Alcohol on Neurotransmitters
When Alcohol enters the blood system, it affects neurotransmitters, the main source of communication within the body. Therefore when a person has short-term alcohol consumption, it depresses the brain function and alters the balance between inhibitory and excitatory neurotransmission systems (Yang et al., 2022). This depression is mainly related to some of the behaviors people undertake when they are under Alcohol. When there is long-term alcohol consumption, it can lead to attempts by the brain to achieve equilibrium.
Specific Neurotransmitters Affected by Alcohol
Alcohol does not only negatively impact neurotransmitters but positively sometimes. For instance, in dopamine, Alcohol positively impacts the dopaminergic reward pathway in the limbic system. Dopamine is released in the ventral tegmental area and acts as a neuromodulating agent, controlling behaviors (Yang et al., 2022). Gaba, the main brain’s inhibitory neurotransmitter, is affected by Alcohol too. When consumed, Alcohol reacts presynaptically with GABA neurons leading to an increase in GABA release. GABA release leads to an increase in sedation and a decrease in anxiety for an individual (Yang et al., 2022). Finally, Alcohol impacts glutamate, the brain’s main excitatory neurotransmitter. Alcohol reduces the number of glutamates in the nucleus accumbens to precede glutamate-mediated signal transmission.
References
Biddinger, K. J., Emdin, C. A., Haas, M. E., Wang, M., Hindy, G., Ellinor, P. T., Kathiresan, S., Khera, A. V., & Aragam, K. G. (2022). Association of habitual alcohol intake with risk of cardiovascular disease. JAMA Network Open, 5(3), e223849–e223849. Web.
Centers for Disease Control. (2019). CDC – Fact Sheets- Moderate Drinking – Alcohol. Centers for Disease Control and Prevention. Web.
Chvilicek, M. M., Titos, I., & Rothenfluh, A. (2020). The neurotransmitters involved in drosophila alcohol-induced behaviors. Frontiers in Behavioral Neuroscience, 14. Web.
Elvig, S. K., McGinn, M. A., Smith, C., Arends, M. A., Koob, G. F., & Vendruscolo, L. F. (2021). Tolerance to alcohol: A critical yet understudied factor in alcohol addiction. Pharmacology Biochemistry and Behavior, 204(45), 173155. Web.
Jones, A. W. (2019). Alcohol, its absorption, distribution, metabolism, and excretion in the body and pharmacokinetic calculations. Wiley Interdisciplinary Reviews: Forensic Science, 1(5). Web.
Yang, W., Singla, R., Maheshwari, O., Fontaine, C. J., & Gil-Mohapel, J. (2022). Alcohol Use Disorder: neurobiology and therapeutics. Biomedicines, 10(5), 1192. Web.
Zhao, X., Zhou, R., Li, H., Fan, Y., Sun, Y., Hu, X., & Zhang, S. (2021). The effects of moderate alcohol consumption on circulating metabolites and gut microbiota in patients with coronary artery disease. Frontiers in Cardiovascular Medicine, 8. Web.