Some of the antihistamines are also used to prevent motion sickness, nausea, vomiting, and dizziness.In patients with Parkinson's disease, diphenhydramine may be used to decrease stiffness and tremors.
Also, in some persons histamine can close up the bronchial tubes (air passages of the lungs) and make breathing difficult.
Antihistamines are used to relieve or prevent the symptoms of hay fever and other types of allergy.
They work by preventing the effects of a substance called histamine, which is produced by the body.
The dozens of types of allergy medication found at your local pharmacy can be overwhelming, but fear not.
Second-generation over-the-counter medications like Claritin, Zyrtec, and Allegra — which improve upon old options like Benadryl by not putting you to sleep — are more similar than they are different.
For example, antihistamines may be used to treat: Many antihistamines are available over the counter at a pharmacy, although some require a prescription.