Cetirizine for hay fever

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Cetirizine for hay fever

This leaflet is about the use of cetirizine for hay fever.

Information-Standard-logoThis leaflet has been written for parents and carers about how to use this medicine in children. Our information sometimes differs from that provided by the manufacturers, because their information is usually aimed at adult patients. Please read this leaflet carefully. Keep it somewhere safe so that you can read it again.

Name of drug

Common brands: Benadryl® Allergy, Piriteze, Zirtek

Why is it important for my child to take this medicine?

Hay fever is an allergic reaction to pollen. The body releases a chemical called histamine, which causes symptoms such as sneezing, runny nose and itchy, watery eyes. Cetirizine blocks the effects of histamine and so reduces the symptoms of hay fever.

People get hay fever at different times of the year depending on the type of pollen they are allergic to. Your child should take cetirizine regularly during their allergy season when the pollen count is high, which will help to keep symptoms under control.

What is cetirizine available as?

  • Tablets: 10 mg
  • Liquid medicine: 5 mg in 5 mL; sugar free versions are available

When should I give cetirizine?

Cetirizine is usually given once or twice each day. 

  • Once a day: it can be given in the morning or the evening.
  • Twice a day: give once in the morning and once in the evening. Ideally, these times are 10–12 hours apart, for example some time between 7 and 8 am, and between 7 and 8 pm. 

Give the medicine at about the same time(s) each day so that this becomes part of your child’s daily routine, which will help you to remember.

How much should I give?

Your doctor will work out the amount of cetirizine (the dose) that is right for your child. The dose will be shown on the medicine label. 

It is important that you follow your doctor’s instructions about how much to give.

How should I give it?

TabletsTablets should be swallowed with a glass of water, milk or juice. Your child should not chew the tablet.

You can crush the tablet and mix it with a small amount of soft food such as yogurt, jam or mashed potato. Make sure your child swallows it straight away, without chewing.

Liquid-medicineLiquid medicine: Measure out the right amount using a medicine spoon or oral syringe. You can get these from your pharmacist. Do not use a kitchen teaspoon as it will not give the right amount.

When should the medicine start working?

Cetirizine starts to work within 30 - 60 minutes after being taken.

What if my child is sick (vomits)?

  • If your child is sick less than 30 minutes after having a dose of cetirizine, give them the same dose again.
  • If your child is sick more than 30 minutes after having a dose of cetirizine, you do not need to give them another dose. Wait until the next normal dose.

If your child is sick again, seek advice from your GP, pharmacist or hospital. They will decide what to do based on your child’s condition and the specific medicine involved.

What if I forget to give it?

If you normally give it once a day in the morning

  • Give the missed dose when you remember during the day.

If you normally give it once a day in the evening

  • If you remember before bedtime, give the missed dose. If you remember after this, you do not need to wake your child up to give them the missed dose. You can give the missed dose in the morning.

If you normally give it twice a day 

  • If you remember up to 4 hours after you should have given a dose, give your child the missed dose. For example, if you usually give a dose at about 7 am, you can give the missed dose at any time up to 11 am. If you remember after that time, do not give the missed dose. Wait until the next normal dose.

What if I give too much? 

Cetirizine is generally a safe drug, and you are unlikely to do harm if you give your child an extra dose of cetirizine by mistake. If you are worried that you may have given your child too much, contact your doctor or local NHS services (111 in England and Scotland; 0845 4647 in Wales). Have the medicine packet with you if you telephone for advice.

Are there any possible side-effects?

We use medicines to make our children better, but sometimes they have other effects that we don’t want (side-effects).

Side-effects you must do something about

If your child gets palpitations (they may feel a fluttery feeling in chest or say that their heart is racing), contact your doctor straight away or take your child to hospital.

Other side-effects you need to know about
  • Your child may feel sleepy, drowsy or sluggish after taking cetirizine. This can last for a few hours, so it may be better to give cetirizine in the evening rather than the morning.
  • Your child may get a dry mouth. Eating citrus fruits (e.g. oranges) or taking sips of water may help.
  • Your child’s eyesight may be blurred (fuzzy).
  • Your child may have constipation (difficulty doing a poo, or doing a poo less often than usual). Encourage them to drink plenty of fluid and to eat foods that contain fibre (e.g. wholemeal foods, fruit and vegetables). If this is still a problem after 2 weeks, contact your doctor. 
  • Your child may find that they urinate (do a wee) less often, or have difficulty doing a wee.
  • Your child may feel light headed and faint (dizziness). Encourage them not to stand up too quickly, and to sit or lie down if they feel dizzy.
  • They may get headaches when they first start taking cetirizine.

There may, sometimes, be other side-effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor. You can report any suspected side-effects to a UK safety scheme at http://www.mhra.gov.uk/yellowcard.

Can other medicines be given at the same time as cetirizine?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.
  • Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal or complementary medicines.

Is there anything else I need to know about cetirizine?

  • If your child continues to get symptoms of hay fever, contact your doctor. They may consider other treatments.
  • Symptoms of eczema and asthma may get worse during the hay fever season. If this happens, contact your doctor.

General advice about medicines 

  • Try to give medicines at about the same times each day, to help you remember.
  • Only give this medicine to your child. Never give it to anyone else, even if their condition appears to be the same, as this could do harm. 
  • If you think someone else may have taken the medicine by accident, contact your doctor for advice.
  • Make sure that the medicine you have at home has not reached the ‘best before’ or ‘use by’ date on the packaging. Give old medicines to your pharmacist to dispose of.

Where should I keep this medicine?

  • Keep the medicine in a cupbord, away from heat and direct sunlight. It does not need to be kept in the fridge.
  • Make sure that children cannot see or reach the medicine.
  • Keep the medicine in the container it came in.

Who to contact for more information 

Your doctor, pharmacist or nurse will be able to give you more information about cetirizine and about other medicines used to treat hay fever.

You can also get useful information from: 
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