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Does Zyrtec (cetirizine) cause side effects?
Zyrtec (cetirizine) is a non-sedating second-generation antihistamine used to relieve symptoms such as sneezing, runny nose, itchy nose and eyes, postnasal discharge, tearing, eye redness, and hives associated with seasonal allergic rhinitis, perennial allergic rhinitis, and hives and itching.
It works by blocking histamine (H-1) receptors on cells. 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. Zyrtec 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, Zyrtec and other second-generation antihistamines do not readily enter the brain from the blood, and, therefore, they cause less drowsiness. Zyrtec may cause more drowsiness than other second-generation antihistamines.
Common side effects of Zyrtec include
Serious but rare side effects of Zyrtec include
Drug interactions of Zyrtec include theophylline, which reduces the breakdown of Zyrtec by 16% and can increase blood levels of Zyrtec. Drugs that cause drowsiness may add to drowsiness resulting from Zyrtec.
Zyrtec has not been adequately evaluated in pregnant women. Available evidence suggests that risk to the developing fetus is low.
What are the important side effects of Zyrtec (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:
Zyrtec (cetirizine) side effects list for healthcare professionals
When Using This Product
- drowsiness may occur
- avoid alcoholic drinks
- alcohol, sedatives, and tranquilizers may increase drowsiness
- be careful when driving a motor vehicle or operating machinery
Stop use and ask a doctor if an allergic reaction to this product occurs. Seek medical help right away.
If Pregnant or Breastfeeding
If breastfeeding: not recommended
If pregnant: ask a health professional before use.
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Related Disease Conditions
What Are the Four Types of Allergic Reactions?
Allergists recognize four types of allergic reactions: Type I or anaphylactic reactions, type II or cytotoxic reactions, type III or immunocomplex reactions and type IV or cell-mediated reactions.
An allergy refers to a misguided reaction by our immune system in response to bodily contact with certain foreign substances. When these allergens come in contact with the body, it causes the immune system to develop an allergic reaction in people who are allergic to it. It is estimated that 50 million North Americans are affected by allergic conditions. The parts of the body that are prone to react to allergies include the eyes, nose, lungs, skin, and stomach. Common allergic disorders include hay fever, asthma, allergic eyes, allergic eczema, hives, and allergic shock.
How Long Does an Allergic Reaction Last?
Allergic reactions may last for varying lengths of time. They may take a few hours to a few days to disappear. If the exposure to the allergen continues, such as during a spring pollen season, allergic reactions may last for longer periods such as a few weeks to months.
Indoor allergens are substances that can cause an allergic reaction in some people. Common sources of indoor allergens include dust mites, cockroaches, molds, pets, and plants. Avoiding indoor allergens is one way to reduce allergy and asthma symptoms.
Hay Fever (Allergic Rhinitis)
Hay fever (allergic rhinitis) is an irritation of the nose caused by pollen and is associated with the following allergic symptoms: nasal congestion, runny nose, sneezing, eye and nose itching, and tearing eyes. Avoidance of known allergens is the recommended treatment, but if this is not possible, antihistamines, decongestants, and nasal sprays may help alleviate symptoms.
Cold, Flu, Allergy Treatments
Before treating a cold, the flu, or allergies with over-the-counter (OTC) medications, it's important to know what's causing the symptoms, which symptoms one wishes to relieve, and the active ingredients in the OTC product. Taking products that only contain the medications needed for relieving your symptoms prevents ingestion of unnecessary medications and reduces the chances of side effects.
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Sinus Infection vs. Allergies
Both sinus infections and allergies (allergic rhinitis) cause symptoms such as runny or stuffy nose and fatigue. Sinus infection (known as sinusitis) is inflammation of the sinuses, caused by infection from bacteria, viruses, and/or fungi (molds). Allergic rhinitis occurs when certain allergies cause nasal symptoms. When a person with allergies breathes in an allergen, such as pollen, dust, or animal dander, symptoms such as runny or stuffy nose, itching, sneezing, and fatigue occur.
The allergic cascade refers to allergic reactions that happen in the body in response to allergens. A variety of immune cells and chemical messengers participate in the allergic cascade. Symptoms of the allergic cascade range from mild swelling and itching to full-blown anaphylactic shock. Allergen avoidance and medications are used to prevent or treat allergies.
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COVID-19 vs. Allergies
Though there is some overlap in allergy and COVID-19 signs and symptoms there are also significant differences. Symptoms that they have in common include headache, fatigue, tiredness, shortness of breath, wheezing, and sore throat. Fever does not occur with allergies but is one of the defining symptoms of COVID-19 infections.
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Treatment & Diagnosis
Medications & Supplements
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.
Professional side effects and drug interactions sections courtesy of the U.S. Food and Drug Administration.