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Second-Generation Antihistamine✓ Over-the-counter

What Is Cetirizine (Zyrtec) Used For?

Brand names: Zyrtec, Reactine

Cetirizine is a popular second-generation antihistamine that relieves allergy symptoms with less drowsiness than older antihistamines.

What is Cetirizine used for?

Hay fever (seasonal allergies)
Year-round allergies
Hives (urticaria)
Allergic skin reactions
Allergic conjunctivitis
Pet allergies

How does Cetirizine work?

Cetirizine blocks histamine H1 receptors, preventing histamine from triggering allergy symptoms like runny nose, itching, sneezing, and watery eyes.

Dosage information

💊Available forms

5mg tablets
10mg tablets
1mg/ml syrup
10mg dissolving tablets

📏Typical dosage

Adults and children over 6: 10mg once daily. Children 2–6: 5mg once daily. Any time with or without food.

⚠️ Dosage varies by individual. Always follow your doctor's or pharmacist's instructions — never self-dose based on general information.

Side effects

Common

Drowsiness (less than older antihistamines)
Dry mouth
Headache
Fatigue
Dizziness

⚠️ Serious — contact your doctor

Severe allergic reaction to the drug itself (rare)
Urinary retention (rare)

Important warnings

May cause drowsiness — be cautious when driving

Alcohol increases drowsiness

Lower doses for kidney or liver problems

Drug interactions

These substances may interact with Cetirizine. This is not a complete list — always tell your doctor and pharmacist ALL medications and supplements you take.

Alcohol (increased sedation)Other sedating medicationsRitonavir

Pregnancy & breastfeeding

🤰 Generally considered safe — discuss with your doctor

Always consult your doctor or obstetrician before taking any medication during pregnancy or while breastfeeding.

Frequently asked questions

What is cetirizine (Zyrtec) used for?

Cetirizine relieves allergy symptoms including runny nose, sneezing, itchy/watery eyes, and hives. Treats seasonal and year-round allergies.

Does cetirizine cause drowsiness?

Less than older antihistamines. About 10–15% of people still experience some drowsiness. Taking it at night can help.

How long does cetirizine take to work?

Typically starts within 1 hour and provides relief for 24 hours. Daily use gives better results than only taking when symptomatic.

What's the difference between cetirizine and loratadine?

Cetirizine works faster and may be stronger but causes drowsiness in more people. Loratadine (Claritin) is considered slightly less sedating.

Can I take cetirizine every day?

Yes — safe for daily long-term use. Studies show no significant safety concerns with extended daily use at recommended doses.

Related medications

💊LoratadineSecond-Generation Antihistamine 💊DiphenhydramineFirst-Generation Antihistamine / Sleep Aid 💊MontelukastLeukotriene Receptor Antagonist

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This is an information resource — not medical advice.

🚨 If you are experiencing a medical emergency or think you may have taken too much of a medication, call emergency services (911 in the US) or go to your nearest emergency room immediately.

Information on this page is sourced from general pharmaceutical references and is provided for educational purposes only. Drug information may change — always verify with your pharmacist or prescriber. PillCodex.com is not affiliated with any pharmaceutical company.