Mixing Alcohol and Medications: What are the Risks?

 

You’ve probably seen this warning on medications you’ve taken. Mixing alcohol with certain       medications can cause nausea and vomiting, headaches, drowsiness, fainting, or loss of coordination.   It also can put you at risk for internal bleeding, heart problems, and difficulties in breathing (1).     Alcohol (ethanol) is one of the most widely consumed psychoactive substances in the world (2).     Despite its social acceptability, simultaneous use of alcohol and medications can lead to serious         pharmacologic and clinical consequences. Alcohol use remains prevalent across populations, including  patients undergoing drug therapy. Chronic ethanol exposure alters gene expression related to mitochondrial function, immune signaling, and neurotransmitter systems (5).

How Alcohol Affects the Body

Ethanol acts as a central nervous system (CNS) depressant, by enhancing GABA activity, inhibiting glutamate, and boosting dopamine. In the liver, it’s metabolized by alcohol dehydrogenase and CYP2E1, which are both key players in drug metabolism. Alcohol disrupts the neurochemical and autonomic systems, causing irregular emotional and stress responses, decreased heart rate variability, and chronic headaches or mood swings. These effects can drive individuals to drink more to relieve stress, reinforcing addiction. Alcohol also impairs neurological functions like sleep, body temperature regulation, and coordination. It affects the hypothalamus, leading to heat loss, disrupted REM sleep, and insomnia during withdrawal (6).

Figure 1: A diagram showing the effects of ethanol on the CNS (6)

The impact of alcohol consumption on chronic and acute health outcomes is largely determined by the total volume of alcohol consumed and the pattern of drinking, especially those patterns which are associated with the frequency of drinking (3). Chronic alcohol use damages the cerebellum, resulting in poor muscular coordination, staggering, and peripheral neuropathy. Over time, alcoholics may develop nerve damage and partial paralysis. Neuropsychological tests reveal cognitive impairments such as poor learning, memory loss, and personality changes. (6)

Figure 2: A figure showing the Pharmacokinetics, Determinants of BAC and Predicting BAC (7)

When Two Drugs Collide

         Mixing alcohol with other depressants, for example benzodiazepines, opioids, or sleep aids, can lead to additive CNS effects, increasing risks of respiratory depression and overdose. Even small amounts of alcohol can quickly intensify sedation. Combining substances intensifies their effects, increasing the risk of overdose, injury, organ damage, and risky behaviors. Alcohol mixed with these depressants can cause severe health problems, including slowed breathing, impaired judgment, and brain or organ damage. These combinations also raise the likelihood of developing substance use disorders (4).

        The effects of alcohol vary across different population groups.  For example, when a woman drinks, the alcohol in her bloodstream typically reaches a higher level than a man’s even if both are drinking the same amount. This is because women’s bodies generally have less water than men’s bodies, showing that a given amount of alcohol is more concentrated in a woman’s body than in a man’s. As a result, women are more susceptible to alcohol-related damage to organs such as the liver. Older generations are also at a higher risk for alcohol-medication interactions. Aging slows the body’s ability to break down alcohol, so therefore alcohol remains in a person’s system longer. Older people also are more likely to take a medication that interacts with alcohol and oftentimes they need to take more than one of these medications. (1)

Conclusion

        Mixing alcohol and medications is more than a simple warning. It’s a pharmacologic event that can change how drugs are absorbed, metabolized, and experienced. Although alcohol is widely consumed and socially accepted, its interaction with prescription, over-the-counter, or illicit drugs can lead to dangerous physiological and neurological effects. Alcohol’s role as a central nervous system depressant amplifies the sedative properties of other substances, increasing the likelihood of respiratory depression, and addiction (8).

        Chronic consumption further harms the brain, liver, and nervous system, impairing coordination, memory, and emotional regulation (4). These risks are heightened in vulnerable populations, such as women and older adults, whose bodies process alcohol differently or more slowly. Understanding these interactions is crucial for preventing health complications and consulting with healthcare professionals is best practice. Different doses affect different people, and it should be recognized that even moderate alcohol use can have severe consequences when combined with other drugs.

By Alyssa Colemen, a Master’s of Medical Science student at the University of Kentucky.

References

 1.  Harmful interactions: Mixing alcohol with medicines. (n.d.-b). https://www.niaaa.nih.gov/sites/default/files/publications/Harmful_Interactions.pdf

2.  MacKillop, J., Agabio, R., & Feldstein Ewing, S. W. (2022, December 22). Hazardous drinking and Alcohol Use Disorders. Nature reviews. Disease primers. https://pmc.ncbi.nlm.nih.gov/articles/PMC10284465/

3.  World Health Organization. (n.d.). Alcohol. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/alcohol

4.  Centers for Disease Control and Prevention. (n.d.). Drinking alcohol while using other drugs can be deadly. Centers for Disease Control and Prevention.  https://www.cdc.gov/alcohol/about-alcohol-use/other-drug-use.html

 

5.  Ethanol metabolism - an overview | sciencedirect topics. (n.d.-a). https://www.sciencedirect.com/topics/neuroscience/ethanol-metabolism

6.  Griffith, C. (n.d.). The Neural Effects of Alcohol. Open Access Text. https://www.oatext.com/the-neural-effects-of-alcohol.php

7.  Goldman, M. R., Molina-Castro, M., & Etkins, J. C. (2025, October 1). Recent advances in alcohol metabolism: From the gut to the brain. Physiological reviews. https://pmc.ncbi.nlm.nih.gov/articles/PMC12345593/

    8.  U.S. Department of Health and Human Services. (n.d.). Alcohol-medication interactions:         Potentially dangerous mixes. National Institute on Alcohol Abuse and             Alcoholism.https://www.niaaa.nih.gov/health-professionals-communities/core-resource-on-    alcohol/alcohol-medicatio n-interactions-potentially-dangerous-mixes