Like all medications, cetirizine can cause side effects in some people. Most side effects of cetirizine are mild and last a short amount of time.
Common side effects (affecting 1 in 10 people) include:
- dizziness
- drowsiness (feeling sleepy)
- dry mouth
- diarrhoea (frequent, runny, or watery poo)
- nausea (feeling sick)
- headache
- fatigue ( feeling tired and low in energy)
- sore throat, and cold-like symptoms (more common in children)
If you experience the above side effects and they are causing you distress, getting worse, or not going away, talk to your GP or pharmacist about an alternative medication.
Uncommon side effects (affecting 1 in 100 people) include:
- agitation (feeling nervous or anxious)
- abdominal (stomach) pain
- severe fatigue (feeling tired and low in energy)
- paraesthesia ( abnormal sensations in the skin such as burning, prickling, tingling, numbness, or itching)
- itchy rash
- feeling generally unwell
Rare side effects (affecting 1 in 1000 people) include:
- changes in your mood such as depression (feeling sad, or low in mood) or aggression (feeling angry or hostile)
- confusion
- hallucinations (hearing or seeing things)
- hives (an itchy rash on the skin)
- insomnia (difficulty sleeping)
- fast heartbeat
- water retention (when your body tissues hold more water than usual)
- weight gain
- liver problems
Very rare side effects (affecting 1 in 10,000 people) include:
- unusual bruising or bleeding caused by low blood platelets
- changes in vision like blurring or difficulty focusing
- involuntary movements like tics, spasms, tremors, or muscle contractions
- problems urinating (peeing) or controlling urination
If you experience any of the above side effects, stop taking your medication and contact your GP or healthcare provider.
Cetirizine is a non drowsy antihistamine, but it can still cause drowsiness in some people. Do not drive, participate in potentially dangerous activities, or operate machinery if you feel sleepy after taking cetirizine.
In very rare cases a severe allergic reaction called anaphylaxis can occur after taking cetirizine. Call an ambulance immediately if you experience any of the following symptoms:
- swelling of the face, throat, lips, or tongue
- a red, itchy rash
- blistering and peeling skin
- difficulty breathing
- collapse
How long do cetirizine side effects last?
Cetirizine stays in your system for around 24 hours. Some side effects such as headaches normally improve after around a week of taking your medication. If you find your side effects unpleasant, or if they are getting worse, or not going away, talk to your doctor or pharmacist about switching to a different medication.
What to do if you get cetirizine side effects
Below are some of the most common side effects of cetirizine, and some things you can do to reduce or alleviate them.
Side effect
|
What you can do |
Headaches |
- Drink plenty of fluids
- Take a painkiller. Your GP or pharmacist can recommend one.
- Avoid alcohol.
- If your headaches are severe, or not going away, talk to your doctor about trying a different medication.
|
Drowsiness |
Talk to your doctor or pharmacist about switching to a different medication. |
Dry mouth |
- Drink plenty of water.
- Chewing sugar-free gum or sucking sugar-free sweets can also help.
|
Diarrhoea |
- Drink plenty of fluids.
- If you have signs of dehydration such as extreme thirst, peeing less than usual, dark coloured pee, dry mouth and tongue, dizziness, and lack of energy, contact your GP or healthcare provider.
- If your diarrhoea gets worse or doesn’t go away, talk to your GP about switching to a different medication.
|
Drowsiness |
Talk to your GP or pharmacist about switching to a different medication. |
Nausea (feeling sick) |
- Take your medication with food.
- Stick to small, plain food and avoid spicy or greasy food.
|
Sore throat |
- Take painkillers recommended by your GP or pharmacist.
- If you are over 16 years of age, try gargling with a soluble aspirin or medicated mouthwash.
|
Cold-like symptoms (sneezing, blocked or runny nose) |
Talk to your GP or pharmacist about switching to a different medication. |
Dizziness |
Sometimes cetirizine can make you feel dizzy or shaky especially when you stand up. Try sitting down until the feeling has passed, and when you stand from a sitting position do so slowly. If your dizziness gets worse or does not go away, talk to your GP or pharmacist about switching to a different medication. |
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