ZYRTEC – Allergy Relief, Side Effects & Dosage



Allergies are a widespread health condition, especially during spring and summer. For patients who are allergic to pollen and other environmental irritants, allergens can negatively impact quality of life for many months each year. Zyrtec (also available as a generic under the name of Cetirizine) helps relieve allergy symptoms. Available as syrup or tablets, it is an antihistamine manufactured by Pfizer and belongs to a all new modern class of drugs that reduce and eliminate allergic reactions. This antihistamine has been in use since 1996 when it was given the green light by the FDA. It is safe for children as long as it is given under the supervision of a qualified doctor.

It is ideal for many types of allergic reactions including (but not limited to):

– Watery eyes
– Runny nose
– Nasal congestion
– Sneezing
– Itching

How Does ZYRTEC Work? How Long Does ZYRTEC Take To Work? How Long Does ZYRTEC Last?

Zyrtec is an antihistamine which works by blocking histamine receptors from releasing chemicals which lead to a cascade of biological reactions culminating in sneezing, itchiness, watery eyes and sniffling. It specifically targets histamine H1 receptor in the body, switching off the resultant reaction. What’s great about this new drug is the fact that it doesn’t enter the brain from the bloodstream, which in effect lessens drowsiness and motor impairment compared to first generation drugs such as Allegra and Claritin.

A single dose of Zyrtec usually takes only 1 hour to start working, and it keeps allergy symptoms under control for roughly 24 hours.

ZYRTEC Side Effects

Zyrtec may impair your thought process as well as motor skills. It is therefore advised not to drive or operate heavy machinery while on it. Stop taking Zyrtec if you experience breakthrough itching, and see your doctor if your condition doesn’t improve after 6 days of being on this medication.

Side effects include:

1. Dry mouth
2. Pounding heartbeat
3. Drowsiness (Zyrtec can make you sleepy)
4. Dizziness
5. Stomach pain
6. Tinnitus
7. Constipation
8. Fatigue

ZYRTEC Contraindications

Before taking it, make sure to tell your doctor or your pharmacist if you are allergic to hydroxyzine, levocetirizine or any other constituent ingredients in this medication. You should also disclose and discuss your medical history, especially if you have kidney or liver problems, have difficulty passing urine due to an enlarged prostate, have diabetes or a mental condition such as anxiety or depression.


The recommended daily dose is 5mg to 10mg for patients over 12 years old.