Cetirizine is known as a non-drowsy antihistamine. It's much less likely to make you feel sleepy than some other antihistamines.

Undesirable effects are described according to MedDRA System Organ Class and by estimated frequency based on post-marketing experience. Different medications, including antihistamines used to treat hay fever, can be problematic when taken together, so it’s better to be safe than sorry. Although there's currently no cure for hay fever, you can make certain tweaks to your lifestyle to help ease hay fever symptoms. Frequencies are defined as follows: Very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1,000 to <1/100); rare (≥ 1/10,000 to < 1/1,000); very rare (<1/10,000), not known (cannot be estimated from the available data). Now we know which antihistamines are non-drowsy, we can take a look at our drowsy antihistamines too.Antihistamine tablets and liquids are available over the counter from a pharmacy without the need for a prescription. Antihistamine nasal sprays are only available on prescription. Antihistamines can be used on their own for mild cases of hay fever, or with other products. Your GP or pharmacist can advise you on what treatments are most suitable for you. Elderly: Following a single 10 mg oral dose, half-life increased by about 50 % and clearance decreased by 40 % in 16 elderly subjects compared to the younger subjects. The decrease in cetirizine clearance in these elderly volunteers appeared to be related to their decreased renal function. You may only need to take Cetirizine on a day you have symptoms - for example, if you have been exposed to a trigger like animal hair.

Non-drowsy - non-drowsy antihistamines are less likely to make you feel sleepy – such as cetirizine, fexofenadine and loratadine. Clinical studies have shown that cetirizine at the recommended dosage has minor undesirable effects on the CNS, including somnolence, fatigue, dizziness and headache. In some cases, paradoxical CNS stimulation has been reported. If you forget to give a dose to a child who is taking cetirizine twice a day, you can give the missed dose if it's within 4 hours of when they should have had it. Antihistamines that are less likely to cause drowsiness, although this can occasionally happen to some people (including cetirizine, acrivastine and loratadine) Antihistamines are medicines often used to relieve symptoms of allergies, such as hay fever, hives, conjunctivitis and reactions to insect bites or stings.If you're struggling with your hay fever symptoms, ask your pharmacist for advice on different treatment options that may be suitable for you, or use the Boots Hayfever Treatment Online Clinic* Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take cetirizine film-coated tablets. At therapeutic doses, no clinically significant interactions have been demonstrated with alcohol (for a blood alcohol level of 0.5 g/L). Nevertheless, precaution is recommended if alcohol is taken concomitantly.