Benadryl is an antihistamine some people take to manage allergy symptoms. However, there are risks of taking Benadryl with alcohol.

Benadryl is the brand name for an antihistamine known as diphenhydramine. The drug helps to reduce allergy symptoms, including rashes and coughs and irritated eyes, throat, and nose.

While it does not impact on the liver, Benadryl is a central nervous system (CNS) depressant, the same as alcohol. When it is taken with alcohol, the combined impact on the CNS can produce heightened side effects. In some situations, this interaction can produce very dangerous results.

There are many potential risks when mixing Benadryl and alcohol. Ten of them are listed here.

1. Drowsiness

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Benadryl is a brand of antihistamines commonly used for allergies.

Benadryl can cause side effects, including sedation and drowsiness, which impair coordination and reaction speed.

Mixing Benadryl with alcohol can intensify these side effects and will impair a person’s daily functioning.

This can be life-threatening if it involves certain activities, such as driving or operating heavy machinery.

2. Loss of consciousness

Some people are more prone than others to losing consciousness when sedated. In these people, combining Benadryl and alcohol is more likely to cause a loss of consciousness. This can be harmful due to the likelihood of falls and other accidents.

3. Dehydration

Benadryl and alcohol are both known to dehydrate the body. Mixing them can increase the risk of dehydration. This can cause discomfort at the time and may worsen a hangover.

4. Complications in older adults

Aging slows the body’s ability to break down alcohol so that it may stay in the system of an older adult for longer than someone younger. This slowdown increases the time a person will be at risk of a harmful interaction between Benadryl and alcohol.

5. Learning and memory impairment

Benadryl blocks the action of a neurotransmitter called acetylcholine. Acetylcholine is necessary for learning and memory, so blocking its action may temporarily impair these processes.

Alcohol is also known to inhibit learning and memory temporarily. So, combining alcohol and Benadryl may again have a more noticeable effect on learning and memory.

6. Interactions with other types of medication

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Benadryl may interact with cough and cold medication.

Benadryl may interact with other types of medication, which can heighten the side effects.

Taking these other types of medications with alcohol could also increase the risk of side effects.

Examples of medications that may interact with Benadryl include:

  • antidepressants
  • stomach ulcer medicine
  • cough and cold medicine
  • other antihistamines
  • diazepam (Valium)
  • sedatives

7. Other sources of alcohol

Some types of medication, including cough syrup and laxatives, also contain alcohol. They can include up to 10 percent alcohol, which may interact with Benadryl.

As a consequence, taking Benadryl with these medications when consuming very small amounts of alcohol may still increase the risk of adverse side effects.

8. Sex

In general, females are more susceptible to alcohol-related harm. This is because their bodies typically contain less water for alcohol to mix with, meaning that the same amount of alcohol would be more concentrated in a female than in a male.

Mixing Benadryl with alcohol may be particularly hazardous for females, as consuming smaller amounts of alcohol could trigger adverse interaction effects.

9. Misuse

As Benadryl and alcohol both cause drowsiness and sedation, it may seem tempting to exploit this combination as a sleeping aid. However, this can also heighten other adverse side effects that will interfere with sleep, such as nausea and dizziness.

10. Dementia

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More studies are required to determine if mixing Benadryl and alcohol causes dementia.

One study found that people who take one anticholinergic drug per day for at least 3 years have a raised risk of dementia. It should be noted that this study included all anticholinergic drugs, not just Benadryl.

Another study in 2018 found excessive alcohol consumption to be associated with a higher risk of dementia. It is possible that consuming large amounts of Benadryl and alcohol over long periods of time could be linked to an increased risk of dementia.

However, longitudinal research would be required in people who consume high levels of Benadryl and alcohol to know whether this has any effect on the risk of dementia.

The risks associated with mixing Benadryl and alcohol may not apply to everyone or every situation. It is possible that consuming small amounts of alcohol while taking Benadryl in a safe environment will cause no harm. However, the safest option is simply to abstain from alcohol while taking Benadryl.

Under no circumstances should Benadryl and alcohol be mixed before engaging in any activity that required mental alertness, such as driving.

If someone else has either intentionally or unintentionally mixed Benadryl with alcohol, it is important to ensure they are in a safe environment, where they can rest, if need be.

It is best to consult with a doctor to determine when it would be safe to consume alcohol after taking Benadryl, as this will depend on other factors, such as age or other courses of medication.