What Is the Main Side Effect of Antihistamines?

Reviewed on 2/14/2022

Woman feeling dizzy and leaning head against a wall
The main side effect of first-generation antihistamines is drowsiness or sleepiness. Other common side effects of antihistamines include dry nose, dry mouth, dizziness, headache, nausea, vomiting, blurred vision, confusion, and irritability.

Antihistamines are medicines used to treat allergy symptoms. The body produces a chemical in the body called histamine when exposed to allergens. Histamines are released to attack allergens but they cause symptoms associated with allergies such as itching, sneezing, runny nose, hives, and itchy and watery eyes. 

Antihistamines may also be used to treat other conditions such as: 

The main side effect of first-generation antihistamines is drowsiness or sleepiness. This can also occur to a lesser extent with second-generation antihistamines 

Other common side effects of antihistamines include: 

What Are Types of Antihistamines?

There are two types of antihistamines: 

Antihistamines are available as pills, liquids, gels, nasal sprays, and eye drops depending on the specific medicine and its use. Many are available over-the-counter (OTC) and some require a doctor’s prescription.

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Reviewed on 2/14/2022
References
Image Source: iStock Images

https://familydoctor.org/antihistamines-understanding-your-otc-options/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3650962/

https://www.aocd.org/page/Antihistamines