"Rapid Acting – Non-Drowsy – Once a Day” Zyrtec is an antihistamine used to treat seasonal rhinitis and conjunctivitis (hayfever), pruitus (itching) of allergic origin, and insect bites. It is fast acting, (usually within 20 minutes of taking) non-sedating and its effect lasts for 24 hours. Active Ingredient Cetirizine hydrochloride 1mg/ml Dosage For Children 1-6 years, 2.5ml twice daily, or 5ml once daily. Adults and Children over 6 years, 5ml twice daily or 10ml once daily. A measuring spoon is provided. Caution Do not exceed a maximum dose. People with kidney problems, and pregnant or breast-feeding women should seek medical advice before taking this medicine. Although this medicine is unlikely to affect your ability to drive or operate machinery, a few people may be impaired and care should be taken. Pharmacy Only Medicine This website does not contain all the information available on this medicine. It does not take the place of talking to your doctor or pharmacist. All medicines have risks and benefits. If you have any questions about using this medicine please feel free to ask us.