Antihistamine medications are a class of drugs commonly used to relieve allergy symptoms and manage various allergic conditions. They work by blocking the effects of histamine, a chemical released by the body in response to allergens.
First-generation antihistamines have been in use for many years. They are effective but often cause drowsiness and may impair cognitive and motor skills.
- Diphenhydramine (brand name: Benadryl)
- Chlorpheniramine (brand name: Chlor-Trimeton)
- Clemastine (brand name: Tavist)
- Promethazine (brand name: Phenergan)
Second-generation antihistamines are newer and have been developed to reduce drowsiness and other side effects.
- Loratadine (brand name: Claritin)
- Cetirizine (brand name: Zyrtec)
- Fexofenadine (brand name: Allegra)
- Ketotifen (brand name: Zaditor)
Third-generation antihistamines are similar to second-generation antihistamines plus have a faster onset and longer duration.
- Levocetirizine (brand name: Xyzal)
- Desloratadine (brand name: Clarinex)
- Bilastine (brand name: Blexten)
Prescription antihistamines are used to treat severe allergies or chronic conditions.
- Azelastine (brand name: Astelin)
- Olopatadine (brand name: Patanase)
- Cyproheptadine (brand name: Periactin)