Diphenhydramine And Alcohol: Can This Combination Be Deadly?

Last Updated: July 20, 2020

Authored by Sharon Levy, MD, MPH

Benadryl, the most popular brand of diphenhydramine, is available over-the-counter for the immediate relief of allergies and is also known as a sleeping pill. Since it is so commonly used, people tend to ignore warnings issued about never combining diphenhydramine with alcohol. Unawareness about the dangers of this mix may seriously harm one’s health, even though mixing alcohol and Benadryl can be lethal.

Is It Dangerous To Mix Diphenhydramine And Alcohol?

Benadryl mechanism of action involves blocking the release of histamine, which makes it an H1 receptor antagonist. Histamine is a neurotransmitter produced by the CNS at higher than normal levels when allergens are detected.
When present at an average level, they serve the practical body functions. Perhaps the most important of which is helping a person stay awake and alert. Thus, taking more than the recommended dose may lead to a general feeling of intoxication that people who misuse it like to call a Benadryl high effect.

Risks Of Mixing Diphenhydramine And Alcohol

Listed below are six of the known side effects of taking diphenhydramine and alcohol at the same time:


Benadryl and alcohol have a sedating effect. The combination causes the CNS to lose alertness and so it generally makes one tired. Certain activities, like driving, therefore, must be avoided to prevent accidents and injuries, whether taking diphenhydramine alone or with a drink.


This is why people who think that mixing diphenhydramine HCL and alcohol can help with getting restful sleep are wrong. Dizziness may combine with feelings of drowsiness and escalate to cause a loss of consciousness.

Dry Mouth And Throat

Substance Misuse And Dependency

Benadryl and alcohol are addictive, even when taken separately. Taking these substances together may result in an increased risk of developing a dependency, as well as disorders and other diseases that are closely associated with addiction.

Dementia And Alzheimer’s Disease

Taking diphenhydramine beyond its recommended use or with liquor may also result in short-term memory loss, increased anxiety, and constipation. Dr. Shelly Gray suggests that the condition, termed Benadryl dementia, is real and that it can escalate to the development of Alzheimer’s Disease.

Increased Risk Of Overdose

Extreme regulation of the CNS can cause an OD. Benadryl overdose has been found to lead to increased blood pressure and cardiac arrest.

What Makes Benadryl And Alcohol Mix A Lethal Combination?

In a report issued by the Centers for Disease Control and Prevention, diphenhydramine consistently ranked within the top 15 drugs most frequently involved in drug overdose deaths in the US between 2011 and 2016. According to the same report, diphenhydramine is one of the most common drug of choice of people who committed suicide by drug overdose during the same period. That includes accidental deaths related to Benadryl addiction or misuse.
woman lying on the floor near bottle of alcohol and Benadryl pills
A diphenhydramine-alcohol mix essentially combines the specific risks posed by these substances when taken separately. Anxiety and depression may develop from dependency on this cocktail. When coupled with deteriorating overall health and well-being, Benadryl and alcohol deaths can be expected.
It is highly recommended that use of consumer goods, like mouthwash, which contains alcohol, are also stopped when taking diphenhydramine. In case other medications are taken, it is best to consult with a physician about dangerous diphenhydramine interactions possible.

Health Risks Of Alcohol And Benadryl Use In Seniors

Older adults are recognized to be at a higher risk for experiencing the side effects of either deliberately or accidentally combining intake of Benadryl with alcohol. Here are the top three reasons why a Benadryl-alcohol combination can put seniors at higher risk:

Slower Metabolism

Older people digest alcohol and Benadryl more slowly. Both substances can stay in their system for a longer time. Older adults are likely to experience a more pronounced intensity of all the common side effects of mixing Benadryl with alcohol.

Taking Other Medications Are Common

Benadryl and alcohol can easily interact with other medications. Seniors are also more frequently inclined to self-medicate so that any additional over-the-counter drugs may add negative impact to the bunch of drugs, including diphenhydramine that they are taking, most notably when combined with a drink.
different pill and a glass of alcohol
Many seniors also take a sleeping aid that may contain compounds like diphenhydramine which are inappropriate for use in seniors. Other than increasing the risk of developing Alzheimer’s Disease, drug reactions may also decrease sexual performance, increase the risk for death and injury due to driving accidents, increased risk for renal failure, and brain hemorrhage.

Older Adults Are At Higher Risk For Falls And Injury

According to the CDC, every year in the US, one in four adults aged 65 and older suffer from falls. One person belonging to that age group dies due to a fall every 20 minutes.
As it is, older adults are already at higher risk for falls and injury. With drowsiness, dizziness, and loss of consciousness that may arise from a combination of diphenhydramine and alcohol, the risk significantly increases.

When Is It Safe To Drink After Taking Diphenhydramine?

The half-life of Benadryl is between two and nine hours. Some health and medical conditions may delay the metabolism of diphenhydramine. People who suffer from liver cirrhosis, for instance, have been found to eliminate diphenhydramine from their system at considerably much slower rates.
To be on the safe side, a person taking Benadryl must not take any hard drink for at least over nine hours following the last dose of Benadryl taken. For the same reason, taking Benadryl after drinking is strongly discouraged until after the alcohol’s effects have wholly subsided. The period it takes to eliminate it from the system varies depending on the drink consumed and the level of alcohol it contains.

People who misuse diphenhydramine may choose to stop dependency safely. Benadryl withdrawal symptoms may be experienced and can hamper personal progress. Treating substance dependency is best done under professional supervision to ensure patient safety.

Page Sources

  1. https://sop.washington.edu/higher-dementia-risk-linked-use-common-drugs/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6167400/
  3. https://www.cdc.gov/nchs/data/nvsr/nvsr67/nvsr67_09-508.pdf
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5541127/
  5. https://www.cdc.gov/homeandrecreationalsafety/falls/index.html

Published on: June 5th, 2019

Updated on: July 20th, 2020

About Author

Sharon Levy, MD, MPH

After successful graduation from Boston University, MA, Sharon gained a Master’s degree in Public Health. Since then, Sharon devoted herself entirely to the medical niche. Sharon Levy is also a certified addiction recovery coach.


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