Efrizine (Cetirizine Dihydrochloride)

Cetirizine, sold under the brand name Zyrtec among others, is a second-generation antihistamine used to treat allergic rhinitis (hay fever), dermatitis, and urticaria. It is taken by mouth. Effects generally begin within an hour and last for about a day. The degree of benefit is similar to other antihistamines such as diphenhydramine. 

Indications: Cetirizine is primarily used to treat symptoms associated with allergic conditions, including:

1. Allergic Rhinitis: Relief of symptoms such as sneezing, runny nose, itching, and nasal congestion associated with seasonal or perennial allergic rhinitis (hay fever).
2. Allergic Conjunctivitis: Management of symptoms like redness, itching, and tearing of the eyes due to allergic conjunctivitis.
3. Chronic Urticaria: Treatment of itching and redness caused by chronic idiopathic urticaria (long-term hives without a known cause).

Dosage and Administration: The dosage of cetirizine can vary depending on the age of the individual and the specific formulation (tablet, syrup, or chewable tablet). It is typically taken once daily.

Side Effects: Common side effects of cetirizine may include drowsiness, dry mouth, fatigue, and headache. However, cetirizine is generally considered a non-sedating antihistamine, meaning it is less likely to cause drowsiness compared to some other antihistamines.