Introduction
Cetirizine Hydrochloride (Cetirizine HCl) is a second-generation antihistamine widely used for allergy management. Unlike first-generation antihistamines, Cetirizine causes minimal drowsiness while effectively controlling allergic reactions. It is available in tablets, syrup, chewable tablets, and drops, making it suitable for adults and children.
What is Cetirizine HCl?
Cetirizine HCl is a selective H1 receptor antagonist. Histamine is a chemical released during allergic reactions that causes itching, swelling, redness, and watery eyes. By blocking histamine at H1 receptors, cetirizine reduces these symptoms without affecting other body functions significantly.
Chemical Formula: C21H25ClN2O3
Molecular Weight: 388.89 g/mol
Pharmacological Class: Second-generation antihistamine
How Cetirizine Works (Mechanism of Action)
When allergens (like pollen, dust, pet dander) enter the body:
1. Immune Response: The immune system releases histamine from mast cells.
2. Histamine Effects: Histamine binds to H1 receptors in the nose, eyes, and skin, causing sneezing, runny nose, itching, and hives.
3. Cetirizine Action: Cetirizine binds to these H1 receptors preventing histamine from acting, thus controlling allergy symptoms.
4. Additional Effects: It has mild anti-inflammatory properties and stabilizes mast cells, reducing the release of further histamine.
Uses of Cetirizine HCl
Cetirizine is prescribed for various allergy-related conditions:
Seasonal Allergic Rhinitis (Hay Fever): Sneezing, nasal congestion, itchy eyes caused by pollen.
Perennial Allergic Rhinitis: Year-round allergies caused by dust, mold, or pets.
Chronic Urticaria (Hives): Red, itchy, and swollen skin rashes.
Allergic Conjunctivitis: Red, watery, itchy eyes.
Atopic Dermatitis (Eczema) Relief: Reduces itching in mild eczema cases.
Food Allergies (Symptomatic Relief): Helps manage mild reactions but not suitable for anaphylaxis.
Other Allergies: Insect bites, drug allergies (as per doctor’s advice).
Benefits of Cetirizine HCl
24-Hour Relief: Once-daily dosing effectively controls symptoms for a whole day.
Non-Drowsy Formula: Suitable for daytime use.
Safe for Children: Approved for children above 2 years (with pediatric dosing).
Long-Term Management: Can be used for chronic allergies with minimal sedation.
Improves Quality of Life: Reduces discomfort and allows normal daily activities.
Dosage Guidelines
Age Group Form Recommended Dose
Adults & children ≥12 years Tablet 10 mg once daily
Children 6–12 years Tablet/Syrup 5–10 mg once daily
Children 2–6 years Syrup 2.5–5 mg once daily
Children <2 years Doctor’s guidance only Not generally recommended
Tips:
Take with or without food.
Do not exceed prescribed dosage.
Consult a doctor for kidney or liver disease.
Side Effects of Cetirizine HCl
Common Side Effects:
Mild drowsiness or fatigue
Headache
Dry mouth or throat
Nausea or stomach discomfort
Rare/Severe Side Effects:
Allergic reactions (swelling of face, lips, or tongue)
Severe dizziness
Fast or irregular heartbeat
Important: Stop medication and seek immediate medical attention if severe reactions occur.
Precautions and Warnings
Avoid alcohol or sedatives while taking cetirizine.
Use caution in pregnancy and breastfeeding (consult a doctor).
Adjust dose in kidney or liver impairment.
Not a substitute for emergency anaphylaxis treatment.
Interactions
Other sedating medications: May increase drowsiness.
Alcohol: Can amplify sedative effects.
Other antihistamines: Avoid taking multiple antihistamines without medical advice.
Cetirizine vs Other Antihistamines
Feature Cetirizine HCl Diphenhydramine Loratadine
Sedation Low High Very Low
Duration 24 hours 4–6 hours 24 hours
Pediatric Use ≥2 years ≥6 years ≥2 years
Non-Drowsy ✅ ❌ ✅
Conclusion
Cetirizine HCl is a safe, effective, and convenient antihistamine that provides relief from a wide range of allergic conditions. Its non-drowsy formula makes it ideal for daily use, while its long duration ensures all-day protection. Always consult a healthcare provider for the correct dosage and guidance, especially for children, pregnant women, or patients with chronic diseases.
