Overview
It blocks histamine, a chemical released during allergic reactions. It causes less drowsiness than older antihistamines like diphenhydramine, but some people still feel sleepy.
What it's used for
- Seasonal and indoor allergies: sneezing, runny nose, and itchy eyes
- Hives
How to take it
- Take it once a day, with or without food.
- For children, use the children's product and follow the label by age.
- It works within about an hour.
Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.
Side effects
Common side effects
- Sleepiness
- Dry mouth
- Tiredness
- Sore throat
Warnings
- Ask a provider before using it if you have kidney or liver disease.
- Don't drive until you know whether it makes you sleepy.
- Some people get itching after stopping it after long daily use.
Other medicines, foods, and alcohol
- Alcohol and sedating medicines add to drowsiness.
Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.
Pregnancy and breastfeeding
Ask your provider before using it in pregnancy or while breastfeeding.
Missed doses, overdose, and storage
If you miss a dose
This medicine is often taken only when needed. If you take it on a schedule, take a missed dose when you remember, unless it's almost time for the next one. Don't double up.
If someone takes too much
Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.
Storing it
Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.
Conditions it's used for
Sources
- DailyMed: FDA drug label for Cetirizine (U.S. National Library of Medicine)
- MedlinePlus: Drugs, herbs, and supplements
- FDA: Drugs@FDA
Last updated 2026-11-13.