Indications
Cetirizine is an antihistamine used to relieve allergy symptoms:
- Tablets and syrup: hay fever and year-round allergic rhinitis (sneezing, runny or itchy nose, itchy watery eyes), hives (urticaria) and itchy skin rashes caused by allergy.
- Eye drops: itching of the eyes caused by allergic conjunctivitis.
How It Works
When the body reacts to an allergen such as pollen, dust or pet hair, it releases histamine, which causes itching, sneezing, swelling and redness. Cetirizine blocks histamine (H1) receptors so histamine cannot act, easing these symptoms. It causes less drowsiness than older antihistamines.
Dosage and Administration
- Adults and children aged 12 and over: 10 mg once a day.
- Children 6 to 11 years: 5 mg twice a day (or 10 mg once a day).
- Children 2 to 5 years: 2.5 mg (2.5 ml of 5 mg/5 ml syrup) twice a day.
- Children under 2 years: only if a doctor prescribes it.
- Kidney disease: a lower dose is needed; follow the doctor’s advice.
- Eye drops: usually 1 drop in each affected eye twice a day, about 8 hours apart, for adults and children aged 2 and over.
Tablets can be taken with or without food. For eye drops, do not let the dropper touch the eye.
Interactions
- Alcohol, sleeping pills, sedatives and other medicines that cause drowsiness can increase sleepiness.
- Theophylline and Ritonavir may slightly raise cetirizine levels.
- Stop taking it at least 3 days before an allergy skin test, as it can affect the result.
Contraindications
- Allergy to cetirizine, Levocetirizine, Hydroxyzine or any ingredient.
- Severe kidney failure (tablets and syrup).
Side Effects
Common: drowsiness, tiredness, dry mouth, headache, dizziness and sore throat. Children may sometimes become restless. Eye drops may cause brief stinging, redness or blurred vision.
Get urgent medical help if you have signs of a serious allergic reaction (swelling of the face, lips or throat, difficulty breathing), a fit (seizure), fainting, a fast or irregular heartbeat, or inability to pass urine.
Pregnancy and Lactation
Cetirizine is among the better-studied antihistamines in pregnancy and is not known to harm the baby, but use it only if needed and after asking your doctor. Small amounts pass into breast milk; occasional use at normal doses is usually considered acceptable, but ask your doctor and watch the baby for drowsiness or irritability.
Precautions and Warnings
- It can cause drowsiness in some people; do not drive or use machines until you know how it affects you.
- Use with care in epilepsy and in people at risk of urine retention, such as men with an enlarged prostate.
- Remove soft contact lenses before using eye drops and wait at least 10 minutes before putting them back.
- If symptoms do not improve, or you have breathing difficulty or wheeze, see a doctor.
Overdose
Too much can cause marked drowsiness, confusion, dizziness, tiredness, restlessness (especially in children), fast heartbeat, tremor and difficulty passing urine. Seek medical help, particularly if a child has taken it.
Therapeutic Class
Second-generation (non-sedating) antihistamine.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Discard eye drops 4 weeks after opening, or as stated on the pack.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.