The active ingredient is Cetirizine. Cetirizine is an antihistamine used to treat allergies including hayfever. 

Other ingredients include microcrystalline cellulose, lactose monohydrate, colloidal anhydrous silica, magnesium stearate. The film coat contains hydroxypropylmethyl cellulose, titanium dioxide (E171) and polyethlene glycol.

Do not take Zirtek:

• If you have a severe kidney disease (severe renal failure with creatinine clearance below 10 ml/min)
• If you are allergic to cetirizine dihydrochloride, to any of the other ingredients listed on the product, to hydroxyzine or to any piperazine derivatives (closely related active ingredients of other medicines)
• Pregnancy and breastfeeding
• Zirtek should not be taken by pregnant women. Consult your doctor.
• Driving and using machines

Zirtek is a non-drowsy drug in most people that take this medication. However, if you drive or operate machinery or take part in hazardous activities while taking this medication, you should closely observe your response to the drug.

Common Side Effects (up to 1 in 10 patients)

• Dizziness, diarrhoea, nausea, dry mouth, fatigue, somnolence, pharyngitis, rhinitis (in children)

How to take Zirtek:

• Take with a glass of liquid. The tablet can be divided into 2 equal doses.
• Adults and adolescents above 12 years: 1 tablet daily
• Children between 6 and 12 years: half of a tablet twice daily.