How Often Can You Take Zyrtec (Cetirizine)?

In our latest question and answer, our pharmacist discusses how often you can dose Zyrtec (cetirizine).

Dec 05, 2017

Enqui asked

How frequently can I take Zyrtec (cetirizine)?


Zyrtec (certirizine) is a second generation antihistamine that is dosed once daily (every 24 hours). There are a few situations where twice daily dosing has been used in children which is discussed below.

Zyrtec is most commonly used to treat urticaria, allergic rhinitis, allergies from mold, pets, dust, seasonal allergies from pollen and grasses, as well as post nasal drip. It comes in a variety of dosage forms including tablets, liquid gels, dissolvable tablets, and a solution.

Dosing Recommendations For Zyrtec


Zyrtec 5 mg to 10 mg once daily based on severity of allergy symptoms.


Zyrtec 5 mg to 10 mg once daily. In those over 77 years of age, 5 mg is recommended to avoid side effects and the risk of falls.

Children 6 Years Old & Over

Zyrtec 5 mg to 10 mg once daily. There have been studies that suggest taking 5 mg twice daily (every 12 hours) may be more effective than one 10 mg dose to maintain symptom control for some patients.

Children 2 Years Old To 5 Years Old

Zyrtec 2.5 mg once or twice daily, or 5 mg once daily. Similar to the dosing mentioned above, studies show that twice daily dosing may provide better symptoms control.

Infatnts & Toddlers Aged 6 Months To 2 Years Old

Zyrtec 2.5 mg once every daily. For children 12 months and older, they can potentially be given 2.5mg twice daily.

Overall, Zyrtec is most often often dosed once daily, especially in adults. Children doses range from once to twice daily. If you are experiencing continuous symptoms of allergy, itchy eyes/nose, postnasal drip or congestion, it may be time to see a doctor. He or she may prescribe a nasal steroid for better relief. Zyrtec is generally a safe medication but always consult your doctor first before starting new medications.

Lastly, we want to mention that off-label doses of Zyrtec are sometimes used for resistant cases of uticarta (itching). Studies suggest that 20 mg in adults (10 mg tablet twice daily) is effective and safe to use in certain cases.

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