Antihistamines aren’t a first-line treatment for asthma, but they may help some people with allergic asthma better manage their symptoms.

Treatment for asthma focuses on long-term management and interventions for sudden attacks. First-line medications for asthma open airways, reduce mucus, and bring down inflammation and swelling.

Antihistamines stop the action of histamine, a chemical your body releases during an allergy attack. Although antihistamines are not among the core medications of an asthma treatment plan, blocking histamine can sometimes reduce asthma symptoms.

Antihistamines are not a first-line treatment for asthma. They often treat allergies, however, and can provide some relief to people with allergic asthma.

If allergies trigger your asthma, allergy medications such as decongestants and antihistamines might be a part of your treatment plan.

Research from 2019 found that antihistamines might be an effective asthma treatment for people with allergic rhinitis, aka hay fever. Many people have both conditions. They might result from similar biological mechanisms in the body.

Asthma attacks

Do not use antihistamines to treat an asthma attack. Antihistamines will not have an effect on acute symptoms such as shortness of breath or chest tightness. To best treat these symptoms, doctors recommend using quick-acting rescue inhalers, such as albuterol.

Antihistamines are generally safe for people with asthma. However, it’s best to consult a healthcare professional in cases of:

  • heart rhythm disorder, such as QTc prolongation
  • pregnancy or lactation
  • kidney impairment
  • liver impairment
  • high blood pressure
  • ocular pressure
  • heart disease
  • urinary retention

Side effects are more common with older antihistamines such as diphenhydramine (Benadryl) and may include:

  • drowsiness
  • insomnia
  • dry mouth
  • dizziness
  • tinnitus

Side effects of antihistamines are dose dependent, meaning higher doses may lead to more significant side effects.

The best antihistamine might depend on what works for your specific allergic trigger.

Some common antihistamines are:

Diphenhydramine is an older antihistamine and causes more side effects than newer drugs. It can lead to drowsiness and sedation and lasts about 4–6 hours.

Newer medications such as cetirizine, loratadine, and fexofenadine last longer than diphenhydramine and have fewer side effects. For those reasons, some doctors recommend them over older medications.

Treating asthma usually involves a comprehensive plan of action that includes:

  • reducing exposure to triggers
  • tracking and monitoring symptoms
  • taking asthma medications

Asthma medications typically involve a combination of quick-relief and long-term control medications:

  • quick-relief medications that you take at the first sign of symptoms
  • controller medications that help prevent mucus and swelling
  • combination medications that offer both quick relief and long-term control
  • biologics that target mucus and swelling at the cellular level for specific asthma subtypes

In addition to an antihistamine, your asthma medication might include:

  • bronchodilators to relax and open the airways
  • inhaled or oral corticosteroids to reduce mucus and swelling
  • combined medications that have a corticosteroid and bronchodilator
  • anticholinergics to prevent muscle tightening
  • targeted therapies such as biologics (monoclonal antibodies) given by injection or IV for some subtypes of asthma
  • antibiotics to treat infections that lead to an asthma flare

Another potential treatment for allergic asthma is allergen immunotherapy (AIT). This involves gradually increasing exposure to an allergen in a controlled environment to modify your immune system’s response. It can reduce inflammation that leads to asthma.

There is some evidence AIT can provide relief to people with asthma, although it might not improve lung function. Research from 2017 found AIT can lessen symptoms and reduce the need for medications in people with allergic asthma.

Here are some answers to some common questions about the role of antihistamines in asthma treatment.

Does histamine worsen asthma?

Your body releases histamine during an allergic reaction. Histamine causes airway muscles to tighten and mucus to increase. In people with allergic asthma, the release of histamine during a reaction can lead to an asthma attack and exacerbation of symptoms.

Can antihistamines stop wheezing?

Wheezing in asthma happens when the lower airways narrow. If you have allergic asthma, the release of histamine might lead to this symptom. An antihistamine or a first-line asthma medication, such as a bronchodilator or anticholinergic, might help stop wheezing.

Is albuterol an antihistamine?

Albuterol (Proair, Proventil) is not an antihistamine. It’s a bronchodilator that opens your airways so that breathing is easier. This medication is short acting, lasting about 4–6 hours.

Antihistamines can be an effective add-on treatment for people with allergic asthma. These medications can reduce histamine in your body, which, during an allergic reaction, can cause airways to constrict and fill with mucus.

First-line treatments for asthma include bronchodilators, anticholinergics, and corticosteroids.