What is the best antihistamine?

There is no universally best antihistamine, because the right one depends on what symptoms you have, how sensitive you are to drowsiness, and how well a given drug works for you. Instead of a single winner, think in terms of two groups. Second-generation antihistamines, cetirizine (Zyrtec), levocetirizine (Xyzal), loratadine (Claritin), fexofenadine (Allegra), and desloratadine (Clarinex), are recommended as first-line therapy for everyday allergic rhinitis and hives because they relieve sneezing, itching, and runny nose while causing far less sedation than older drugs.

Among the second-generation options, there are meaningful trade-offs. Fexofenadine (Allegra) is generally considered the least sedating and a good pick if you drive or need to stay sharp. Loratadine (Claritin) is also low-sedation. Cetirizine (Zyrtec) and levocetirizine (Xyzal) tend to be among the most effective for stubborn symptoms but are slightly more likely to cause drowsiness in sensitive people. Because responses vary from person to person, it is reasonable to try one for a couple of weeks and switch if it underperforms or makes you tired.

First-generation antihistamines like diphenhydramine (Benadryl) and chlorpheniramine work, but they cross into the brain and commonly cause drowsiness, dry mouth, and next-day grogginess. They are best kept for occasional short-term use and are generally discouraged as a daily allergy medicine, especially in older adults, where anticholinergic effects raise the risk of confusion and falls.

Importantly, no antihistamine treats a severe, whole-body allergic reaction (anaphylaxis), that is a medical emergency requiring epinephrine and a call to 911. If routine antihistamines are not controlling your allergies, ask a clinician; allergen immunotherapy (allergy shots or sublingual drops) is the only treatment that changes the underlying allergy rather than just masking symptoms.