Cetirizine (Zyrtec): Antihistamine Drug for Allergy and Asthma Prevention

  • Type of Drug: Antihistamine
  • Prescribed for: Seasonal allergy, stuffy and runny nose, itching of the eyes, scratchy throat caused by allergies, and other allergic symptoms, such as rash, itching, or hives. Cetirizine may be prescribed for the treatment of asthma in people whose disease is triggered by allergies
  • Brand Name: Zyrtec

General Information of Zyrtec

Cetirizine causes less sedation than most other antihistamines available in the United States. It has been widely used and accepted by people who find other antihistamines unacceptable because of the drowsiness and tiredness they cause. Cetirizine appears to work in exactly the same way as Chlorpheniramine and other widely used antihistamines.

Cautions and Warnings

Do not take Cetirizine if you are allergic to it.

People with kidney disease should receive a lower than normal dosage of Cetirizine because they are unable to clear the drug as rapidly from their bodies as others.

Possible Side Effects

  • Rare: headache, nervousness, weakness, upset stomach, nausea, vomiting, sore throat, nosebleeds, cough, stuffy nose, changes in bowel habits, and dry mouth, nose, or throat.

Drug Interactions

  • Cetirizine is less likely to interact than other antihistamines.

Food Interactions of Cetirizine (Zyrtec)

Cetirizine should be taken on an empty stomach, 1 hour before or 2 hours after food or meals, although it may be taken with food or milk if it upsets your stomach.

Usual Dose

Adult and Adolescent (age 12 and older): 5 to 20 mg once a day. Reduce dosage in people with kidney disease.
Child (age 6-11): 10 mg a day.
Child (age 2—5): 5 mg a day.


Cetirizine overdose is likely to cause exaggerated side effects. Overdose victims should be given Syrup of Ipecac to make them vomit and then should be taken to a hospital emergency room. ALWAYS bring the prescription bottle with you.

Cetirizine (Zyrtec): Special Information

Report sore throat, unusual bleeding, bruising, tiredness, or weakness or any other unusual side effects to your doctor. This drug is less sedating than most other antihistamines, yet it still may cause some drowsiness and should not be mixed with alcohol or other nervous-system depressants.

If you forget to take a dose of Cetirizine, take it as soon as you remember. If it is almost time for your next regularly scheduled dose, skip the one you forgot and continue with your regular schedule. Do not take a double dose.

Special Populations

Do not take any antihistamine without your doctor’s knowledge. Animal studies of Cetirizine have shown that doses several times larger than the human dose lower the baby’s weight and increase the risk of the baby’s death.
Small amounts of antihistamine medicines pass into breast milk and may affect a nursing infant. Nursing mothers should avoid antihistamines or use alternative feeding methods While taking the medicine.

Seniors are unlikely to experience nervous-system effects with this antihistamine.