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- 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.
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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.
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.
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