- 10 Common Allergy Triggers Slideshow Pictures
- Take the Quiz on Allergies
- Nasal Allergy Relief Products Slideshow
- What is cetirizine, and how does it work (mechanism of action)?
- What brand names are available for cetirizine?
- Is cetirizine available as a generic drug?
- Do I need a prescription for cetirizine?
- What are the side effects of cetirizine?
- What is the dosage for cetirizine?
- Which drugs or supplements interact with cetirizine?
- Is cetirizine safe to take if I'm pregnant or breastfeeding?
- What else should I know about cetirizine?
What is cetirizine, and how does it work (mechanism of action)?
Cetirizine is a non-sedating antihistamine that works by blocking histamine (H-1) receptors on cells. It is similar to the other second generation antihistamines loratadine (Claritin), fexofenadine (Allegra) and azelastine (Astelin). Histamine is a chemical that is responsible for many of the signs and symptoms of allergic reactions, for example, swelling of the lining of the nose, sneezing, and itchy eyes. Histamine is released from histamine-storing cells (mast cells) and then attaches to other cells that have receptors for histamine. The attachment of the histamine to the receptors causes the cells to be "activated," releasing other chemicals that produce the effects that we associate with allergy, for example, sneezing. Certirizine blocks one type of receptor for histamine (the H1 receptor) and thus prevents activation of H1 receptor-containing cells by histamine. Unlike the first generation antihistamines, cetirizine and other second-generation antihistamines do not readily enter the brain from the blood, and, therefore, they cause less drowsiness. Cetirizine may cause more drowsiness than other second generation antihistamines. The FDA approved cetirizine in September 1996.
What are the side effects of cetirizine?
Side effects that have been reported with cetirizine include:
- sleepiness (occurs in 14% of patients),
- dry mouth,
- jitteriness, and
- sore throat.
Other important but rare side effects include:
What is the dosage for cetirizine?
The recommended dose is 5 to 10 mg daily depending on the severity of symptoms.
Which drugs or supplements interact with cetirizine?
Theophylline (Theo-Dur, Respbid, Slo-Bid, Theo-24, Theolair, Uniphyl, Slo-Phyllin)reduces the breakdown of cetirizine by 16% and can increase blood levels of cetirizine. Drugs that cause drowsiness may add to drowsiness resulting from cetirizine.
Quick GuideBad Bugs: Identify Bug Bites From Mosquitos, Spiders and More
Is cetirizine safe to take if I'm pregnant or breastfeeding?
Cetirizine has not been adequately evaluated in pregnant women. Available evidence suggests that risk to the developing fetus is low.
Cetirizine is excreted in human breast milk.
What else should I know about cetirizine?
What preparations of cetirizine are available?
Tablets: 5 and 10 mg. Tablets (Chewable or orally disintegrating): 10 mg. Syrup: 5 mg/5 ml.
How should I keep cetirizine stored?
Cetirizine should be stored in a dry place at 15 C to 30 C (59 F to 86 F).
Cetirizine (Zyrtec, Zyrtec Allergy, Zyrtec Hives) is a drug prescribed to treat seasonal or perennial allergies and hives. Side effects, drug interactions, dosing, and pregnancy safety information should be reviewed prior to taking this medication.
Multimedia: Slideshows, Images & Quizzes
Picture of Fixed Drug Eruption
A large red-violet plaque on the arm of a child. See a picture of Fixed Drug Eruption and learn more about the health topic....
Picture of Urticaria
This is a close-up view of wheals with white-to-light-pink color centrally and peripheral erythema. See a picture of Urticaria...
Related Disease Conditions
19 Tips on How to Stop a Cough
Coughing is a reflex that helps a person clear their airways of irritants. There are many causes of an excessive or severe...
Chronic Rhinitis and Post-Nasal Drip (Symptoms, Treatment)
Chronic rhinitis and post-nasal drip symptoms include an itchy, runny nose, sneezing, itchy ears, eyes, and throat. Seasonal...
Hives (Urticaria & Angioedema)
Hives, also called urticaria, is a raised, itchy area of skin that is usually a sign of an allergic reaction. The allergy may be...
An allergy refers to a misguided reaction by our immune system in response to bodily contact with certain foreign substances. ...
Eye allergy (or allergic eye disease) are typically associated with hay fever and atopic dermatitis. Medications and cosmetics...
Hay Fever (Allergic Rhinitis)
Hay fever (allergic rhinitis) is an irritation of the nose caused by pollen and is associated with the following allergic...
Indoor allergens are substances that can cause an allergic reaction in some people. Common sources of indoor allergens include...
Are Hives (Urticaria) Contagious?
Hives are not contagious are triggered by an allergic response to a substance. Symptoms and signs of hives include a raised,...
Allergy Treatment Begins At Home
Avoiding allergy triggers at home is one of the best ways to prevent allergy symptoms. Controlling temperature, humidity, and...
The allergic cascade refers to allergic reactions that happen in the body in response to allergens. A variety of immune cells and...
Treatment & Diagnosis
- Drugs: Buying Prescription Drugs Online Safely
- Asthma Rates Increasing
- How To Reduce Your Medication Costs
- Pharmacy Visit, How To Get The Most Out of Your Visit
- Indications for Drugs: Approved vs. Non-approved
- Medication Disposal
- Dangers of Mixing Medications
- Drugs: The Most Common Medication Errors
- OTC Cold and Cough Medications
- Generic Drugs, Are They as Good as Brand-Names?
Medications & Supplements
- Antihistamines (Oral)
- Drug Interactions
- Drugs: Questions to Ask Your Doctor or Pharmacist about Your Drugs
- Claritin (loratadine) vs. Zyrtec (cetirizine)
- fexofenadine, Allegra, Allegra Allergy, Allegra Hives, Children's Allegra, Mucinex Allergy
- loratadine, Claritin, Claritin RediTabs, Alavert, Claritin Hives Relief, Children's Claritin
- loratadine and pseudoephedrine (Alavert Allergy & Sinus, Claritin-D, Claritin-D 24 hour)
- fexofenadine and pseudoephedrine, Allegra-D
- azelastine hydrochloride and fluticasone propionate (Dymista)
Prevention & Wellness
Daily Health News
Health Solutions From Our Sponsors
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
FDA Prescribing Information