Antihistamines and Alcohol Interaction

Last Updated: December 18, 2019

Authored by Sharon Levy, MD, MPH

Antihistamines are a class of drugs that are commonly used to treat allergies. They are inexpensive, generic, over-the-counter (OTC) drugs readily available to the general population. As these drugs affect the central nervous system, it is crucial to be cautious of their interaction with alcohol. Can one drinks alcohol with antihistamines? Can alcohol potentiate or inhibit antihistamine effects? Is the antihistamine and alcohol combination safe or deadly? What role do antihistamines play for people predisposed to Asian flush?

How do Antihistamines and Alcohol Interact?

Many people take antihistamines for anxiety or allergy regularly. They may also be consuming alcohol in their daily lives. For such people, it is significant to know how these two interact with each other. Antihistamines are generally safe drugs. As their name suggests, they prevent the physiological effects of histamine, a neurotransmitter involved in the allergic and inflammatory response of the body. Dizziness is one of their significant side effects. Alcohol, on the other hand, also affects the central nervous system and makes a person feel drowsy.

Many people use antihistamines otc. Some people prefer to use herbal antihistamines. As long as they are ingested, they will interact with alcohol. Consuming both at the same time can compound the adverse effects of both drugs, leading to a much dangerous side-effect profile. Topically applied antihistamine creams do not get readily absorbed in the blood, so they may not have any interaction.

Using Antihistamines for “Asian Flush”

Many people try to use antihistamines to prevent the face, neck, and shoulder reddening associated with Asian flush. This works because they stop the blood vessels from dilating. The dilation of blood vessels occurs because of the accumulation of acetaldehyde as people with Asian flush do not have an enzyme called aldehyde hydrogenase 2 (ALDH2) in adequate quantity.
Notwithstanding the visible reddening of the skin, many people predisposed to Asian flush are likely to consume alcohol heavily. This would lead to excessive accumulation of acetaldehyde. Acetaldehyde is a known carcinogen that often develops mouth, pharynx, and oesophageal cancer in heavy drinkers. However, in the case of people with Asian flush taking antihistamines, extreme levels of acetaldehyde will accumulate and lead to the development of these cancers even without heavy drinking.
woman with asian flush
Daryl Davies, who is the director of Alcohol and Brain Research Laboratory at USC, believes that consuming the histamine blockers for Asian flush can lead to stomach cancer, skin cancer, known as squamous cell carcinoma, and oesophageal cancer in alcohol consumers.
Therefore, even though using these medicines can temporarily suppress the effects of Asian flush, the complications of such a practice outweigh the benefits. These drugs are not recommended for treating Asian flush.

Dangers and Side Effects of The Combo

Sedation is the main side effect of both antihistamines and alcohol. Used together, the result is magnified to the extent that it may cause loss of consciousness or even coma. Even if someone consumes non-drowsy antihistamine and alcohol together, there is a good chance of experiencing low blood pressure. According to NIAAA, other dangerous adverse effects of consuming them together include drowsiness, dizziness, and increased risk for overdose.

Apart from drowsiness, older adults may experience dry mouth, headache, or urination problems, too. Over time, this may lead to impairment of memory and learning abilities and even cause dementia.

Simultaneous Consumption and the Possibility of Death

Can one overdoses on antihistamine mixing it with alcohol? Yes, and it can be a deadly overdose. The central nervous system depression can be so severe that it can cause extreme sedation and loss of consciousness. Depressing the central nervous system means decreasing essential living functions like breathing or pumping of the heart. Slowing down of respiration and heart rate, if not treated promptly, often leads to death.
Also, driving after using an antihistamine has an increased risk of road traffic accidents. It is recommended to avoid driving when using them with alcohol. First-generation antihistamines are more dangerous because they have more severe side-effects than second and third-generation ones.

Safe Amount of Alcohol with Antihistamines

The established recommendations for safe levels of drinking are two drinks maximum for men and one drink for non-pregnant women daily.

Even drinking a small amount can significantly increase the side effects and lead to impaired motor ability.

Avoid the Lethal Mix

Although antihistamines are readily available over-the-counter drugs, it is risky to consider them safe, especially for regular alcohol consumers. For alcohol addicts with allergies, their simultaneous use due to unawareness can be fatal. People experiencing Asian flush are at an additional risk of developing cancers early in their life. People should avoid using antihistamine and alcohol together.
Note that the constant use of antihistamine medications can result in addiction. However, this drug dependence is easily treatable. Help and support are available at numerous treatment centers across the US.

Page Sources

  1. Antihistamines prevent ‘Asian flush’ but with huge risks. University of South Carolina.
  2. Harmful Interactions. National Institute on Alcohol Abuse and Alcoholism.

Published on: July 31st, 2019

Updated on: December 18th, 2019

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.


Leave a comment