User:Mr. Ibrahem/Cetirizine
From Wikipedia, the free encyclopedia
Cetirizine, sold under the brand name Zyrtec among others,[5] is an antihistamine used to treat hay fever, dermatitis, and urticaria.[6] It is taken by mouth.[5] Effects generally begin within an hour and last for about a day.[5] The degree of benefit is similar to other antihistamines such as diphenhydramine.[5]
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Pronunciation | /sɛˈtɪrɪziːn/ |
Trade names | Zyrtec, Incidal, others |
AHFS/Drugs.com | Systemic: Monograph Eye: Monograph |
MedlinePlus | a698026 |
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Routes of administration | By mouth |
Drug class | Second-generation antihistamine |
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Bioavailability | Well-absorbed (>70%)[1] |
Protein binding | 88–96%[1] |
Metabolism | Minimal (non-cytochrome P450-mediated)[2][3] |
Onset of action | 20–42 minutes[3] |
Elimination half-life | Mean: 8.3 hours[2][3] Range: 6.5–10 hours[4] |
Duration of action | ≥24 hours[4] |
Excretion | Urine: 70–85%[2] Feces: 10–13%[2] |
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Formula | C21H25ClN2O3 |
Molar mass | 388.89 g·mol−1 |
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Common side effects include sleepiness, dry mouth, headache, and abdominal pain.[5] The degree of sleepiness that occurs with newer histamines is generally less than with first generation antihistamines.[6] Serious side effects may include aggression and angioedema.[6] Use in pregnancy appears safe, but use during breastfeeding is not recommended.[7] It is a second-generation antihistamine and works by blocking histamine H1 receptors, mostly outside the brain.[5]
Cetirizine was patented in 1981 and came into medical use in 1987.[8] It is on the World Health Organization's List of Essential Medicines as an alternative to loratadine.[9] It is available as a generic medication.[6] A month's supply in the United Kingdom costs the NHS just less than £1.20 as of 2021.[6] In the United States the wholesale cost of this amount is about US$2.50.[10] In 2017, it was the 66th most commonly prescribed medication in the United States, with more than eleven million prescriptions.[11][12]