Overview
Cetirizine helps block the effects of histamine, a chemical your body releases during allergic reactions. By reducing histamine activity, cetirizine can relieve symptoms such as:
- Sneezing and runny nose
- Itchy or watery eyes
- Itchy throat
- Skin itching and hives (urticaria)
What is cetirizine used for?
Cetirizine tablets are commonly used for:
- Allergic rhinitis (seasonal or year-round): sneezing, runny/blocked nose, itchy eyes
- Chronic urticaria (hives): itchy raised red welts
- Other allergy-related itching (as advised by a doctor)
How does it work?
Allergens (like pollen, dust mites, pet dander) can trigger your immune system to release histamine. Cetirizine blocks H1 histamine receptors, reducing itching, swelling, watery eyes, and runny nose.
Dosage & how to take it
| Group | Typical tablet dose | Notes |
|---|---|---|
| Adults & ≥12 years | 10 mg once daily | Some people use 5 mg if they get drowsy. |
| Children 6–11 years | 5–10 mg once daily | Depends on weight/doctor advice; many use 5 mg. |
| Children <6 years | Use pediatric form (drops/syrup) | Tablets may not be suitable; dose is different. |
| Kidney problems / elderly | May need lower dose (often 5 mg) | Ask a doctor/pharmacist if you have kidney disease. |
When should you take it?
- Once daily, at the same time each day.
- If it makes you sleepy, take it at night.
- Can be taken with or without food.
If you miss a dose
Take it when you remember. If it’s close to your next dose, skip the missed dose. Do not double dose.
How fast does it work and how long does it last?
- Many people feel relief within 1–2 hours.
- Effects typically last about 24 hours.
Side effects
Cetirizine is usually well-tolerated. Side effects can still happen, especially at higher doses or if combined with alcohol/sedatives.
Common side effects
- Drowsiness or sleepiness
- Dry mouth
- Headache
- Fatigue
- Mild stomach upset
Less common side effects
- Dizziness
- Nausea
- Restlessness (more in some children)
Warnings & who should be careful
- Drowsiness: Avoid driving or risky work until you know how it affects you.
- Alcohol: Alcohol can increase sleepiness and impairment.
- Kidney disease: Dose adjustment may be needed.
- Pregnancy/breastfeeding: Ask your doctor before use.
- Other sedatives: Combining can increase drowsiness.
Drug interactions
Cetirizine has fewer interactions than older antihistamines, but some combinations can still cause problems.
- Alcohol → more drowsiness and reduced coordination
- Sleeping pills / sedatives / some anti-anxiety meds → extra sedation
- Other antihistamines → higher side-effect risk (dry mouth, drowsiness)
antihistamine to avoid accidental duplication.
Practical tips
- If allergies are daily, taking it regularly can work better than “only when bad”.
- For nasal congestion, antihistamines may help less than nasal sprays—ask a pharmacist if congestion is your main symptom.
- Keep windows closed during high pollen days; shower after outdoor exposure.
- Dust mite control (washing bedding, reducing soft toys) helps long-term.
Storage
- Store at room temperature, away from moisture and heat.
- Keep out of reach of children.
- Do not use after expiry date on the strip/box.
FAQ
Is cetirizine a “sleeping tablet”?
No. It’s an allergy medicine, but some people feel sleepy on it—especially at first, or with alcohol.
Can I take cetirizine every day?
Many people do during allergy seasons or chronic hives, but it’s best to follow medical advice if you need it long-term.
Does it work for cough and cold?
It can reduce runny nose/itching if allergies are involved, but it does not treat viral infections directly.
What’s the difference between cetirizine and levocetirizine?
Levocetirizine is a closely related version of cetirizine. Some people find one causes less drowsiness, but it varies.
Medical disclaimer
This site provides general educational information. It does not replace professional medical advice. If symptoms are severe, persistent, or unusual—especially breathing trouble, swelling, or severe rash—seek urgent care.