Cetirizine Side Effects, How it Works, Upsides & Downsides

Cetirizine is an antihistamine that is used to treat allergy symptoms like watery eyes, sneezing, runny nose, itching, and cold. It can also be used to cure swelling and itching caused by hives. It is available in the form of tablets, and in liquid form. Cetirizine works by limiting the production of a natural chemical (histamine) during an allergic reaction, reducing symptoms like itching, runny nose, watery eyes, and sneezing.


However, Cetirizine should not be used to treat hives or a severe allergic reaction like anaphylaxis. If you have been prescribed epinephrine, use it to treat a severe allergic reaction instead of Cetirizine.


Side effects

Cetirizine can treat allergy symptoms and swelling, but it also has some side effects. Most of the side effects are common and may even go away as your body adjusts to the use of Cetirizine. However, visit your doctor immediately if any of the minor side effects persist or worsen.

Minor side effects

  • Dry mouth
  • Fatigue
  • A sore throat
  • Nausea
  • Drowsiness
  • A cough
  • Dizziness
  • Constipation
  • Tiredness
  • Vomiting
  • Stomach pain
  • Headaches


However, some of the side effects are serious and can lead to death if not treated immediately. Seek immediate medical help if you experience any of the following major side effects.

Major side effects

  • Rapid or irregular heartbeat
  • Confusion
  • Insomnia
  • Restlessness or hyperactivity
  • Tremors
  • Little or no urination
  • Weakness
  • Problems with vision
  • Symptoms of an allergic reaction including itching, trouble breathing, dizziness, swelling, and rash


How to use?

Take Cetirizine only according to the prescribed amount, without increasing or decreasing your dose. You can take Cetirizine with food if you feel nauseous. It is advisable to take Cetirizine once every day unless prescribed otherwise by your doctor. Do not take this medicine for longer than it is prescribed. If you are taking the chewable tablet, make sure you chew before swallowing. If you are taking the rapidly-dissolving tablet, keep it on your tongue until it fully dissolves, then swallow, ideally with water. If you are taking the liquid form, it is advisable to use a dose-measuring device to make sure you get the correct dosage. Cetirizine should not take long to take effect; however, visit your doctor if any of the allergy symptoms or hives worsen after using Cetirizine for three days or if your hives do not go away after six weeks.



  • Do not take Cetirizine if you are allergic to any of the active or inactive ingredients found in it, including hydroxyzine and levocetirizine. It is advisable to ask for a list of ingredients from your pharmacist to avoid a severe allergic reaction.
  • Inform your doctor of all the diseases you have had, especially if you have a history of kidney disease, liver disease, or if you have difficulty urinating.
  • As one of the side effects of Cetirizine is drowsiness, avoid operating machinery or driving a car until you are sure about the way Cetirizine affects your body. Avoid drinking any alcoholic beverages or using marijuana as they can worsen these side effects.


  • The liquid form of Cetirizine contains sugar; hence use it with caution if you have diabetes. Consult your doctor about the safe use of Cetirizine.
  • Inform your doctor and dentist of all the medications you are taking before undergoing any surgery.


  • It is uncertain whether Cetirizine can harm an unborn baby and should only be taken if necessary. Consult your doctor about the use of Cetirizine if you are pregnant or plan to become pregnant.
  • Cetirizine can pass into breast milk and can have harmful effects on a nursing infant. Consult your doctor about the use of Cetirizine before breastfeeding.