Cetirizine is an OTC drug used to Treat allergies such as pet allergies, dust mite allergies (seasonal and perennial allergic rhinitis) and hay fever.
- It works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction.
- Treating itchy, allergic skin rashes (urticaria or hives).
- Treating a chronic idiopathic urticaria (chronic itchy nettle-type rash where cause is unknown)
- Cetirizine and other second-generation antihistamines do not readily enter the brain from the blood, and, therefore, they cause less drowsiness as compare to first generation antihistamine.
- The FDA approved cetirizine in September 1996.
Cetirizine side effects
Cetirizine can cause adverse effects, such as:
- Excessive tiredness
- Dry mouth
- Stomach pain
Warnings and precautions
Avoid It if
- You have problems with your kidneys
- You suffer from epilepsy or are at risk of convulsions
- You have predisposition factors of urinary retention (eg: spinalcord lesion, prostatic hyperplasia) as cetirizine increases the risk of urinary retention
Mechanism Of Action of Cetirizine
It is a H1 receptor Blocker Antihistamine agent that works by blocking histamine type(H-1) receptors on cells. It is similar to the other second generation antihistamines fexofenadine,loratadine and azelastine. Histamine is released from mast cells and then attaches to other cells that have receptors for histamine. The attachment of the histamine to the receptors causes the cells to be “activated,” releasing other chemicals that produce the effects that we associate with allergy, for example, sneezing. This drug blocks one type of receptor (H1 Receptor) for histamine and thus prevents activation of H1 receptor-containing cells by histamine. It may cause more drowsiness than other second generation antihistamines.
Dose for Allergies, Hay Fever and Urticaria
- Seasonal allergic and vasomotor rhinitis; relief of symptoms from colds, urticaria,allergic conjunctivitis,anaphylactic reactions,angioedema, pruritus. Use 5-10 mg PO qDay depending on severity of symptoms.
- Do not exceed from 10 mg q Day