Cetirizine Explained

Watchedfields:changed
Verifiedrevid:460026203
Width:250
Width2:250
Tradename:Allacan, Piriteze, Zyrtec, others
Dailymedid:Cetirizine
Pregnancy Au:B2
Routes Of Administration:By mouth
Atc Prefix:R06
Atc Suffix:AE07
Legal Au:Unscheduled
Legal Ca:OTC
Legal Nz:OTC
Legal Uk:GSL
Legal Uk Comment:/ P
Legal Us:OTC
Legal Us Comment:/ Rx-only
Legal Status:OTC / Rx-only
Bioavailability:Well-absorbed (>70%)[1]
Protein Bound:88–96%
Metabolism:Minimal (non-cytochrome P450-mediated)
Onset:20–42 minutes
Elimination Half-Life:Mean: 8.3 hours
Range: 6.5–10 hours[2]
Duration Of Action:≥24 hours
Excretion:Urine

70–85%
Feces: 10–13%

Cas Number:83881-51-0
Pubchem:2678
Iuphar Ligand:1222
Drugbank:DB00341
Chemspiderid:2577
Unii:YO7261ME24
Kegg:D07662
Chebi:3561
Chembl:1000
Iupac Name:(±)-[2-[4-[(4-Chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetic acid
C:21
H:25
Cl:1
N:2
O:3
Smiles:Clc1ccc(cc1)C(c2ccccc2)N3CCN(CC3)CCOCC(=O)O
Stdinchi:1S/C21H25ClN2O3/c22-19-8-6-18(7-9-19)21(17-4-2-1-3-5-17)24-12-10-23(11-13-24)14-15-27-16-20(25)26/h1-9,21H,10-16H2,(H,25,26)
Stdinchikey:ZKLPARSLTMPFCP-UHFFFAOYSA-N

Cetirizine is a second-generation antihistamine used to treat allergic rhinitis (hay fever), dermatitis, and urticaria (hives). It is taken by mouth. Effects generally begin within thirty minutes and last for about a day. The degree of benefit is similar to other antihistamines such as diphenhydramine, which is a first-generation antihistamine.

Common side effects include sleepiness, dry mouth, headache, and abdominal pain. The degree of sleepiness that occurs is generally less than with first-generation antihistamines because second-generation antihistamines are more selective for the H1 receptor.[3] Compared to other second-generation anti-histamines, cetirizine can cause drowsiness. Second-generation antihistamines that do not cause drowsiness are fexofenadine, and loratadine.

Use in pregnancy appears safe, but use during breastfeeding is not recommended.[4] The medication works by blocking histamine H1 receptors, mostly outside the brain.[5]

Cetirizine can be used for paediatric patients. The main side effect to be cautious about is somnolence.[6]

It was patented in 1983[7] and came into medical use in 1987.[8] It is on the World Health Organization's List of Essential Medicines.[9] It is available as a generic medication.[10] In 2021, it was the 49th most commonly prescribed medication in the United States, with more than 13million prescriptions.[11] [12]

Medical uses

Allergies

Cetirizine's primary indication is for hay fever and other allergies. Because the symptoms of itching and redness in these conditions are caused by histamine acting on the H1 receptor, blocking those receptors temporarily relieves those symptoms.[13]

Cetirizine is also commonly prescribed to treat acute and (in particular cases) chronic urticaria (hives), more efficiently than any other second-generation antihistamine.

Available forms

Cetirizine is available over-the-counter in the US in the form of 5 and 10 mg tablets. A 20 mg strength is available by prescription only. It is also available as a 1 mg/mL syrup for oral administration by prescription. In the UK, up to 30 tablets of 10 mg are on the general sales list (of pharmaceuticals) and can be purchased without a prescription and without pharmacist supervision.[14] The drug can be in the form of tablets, capsules or a syrup.

Adverse effects

Commonly reported side effects of cetirizine include headache, dry mouth, drowsiness, and fatigue, while more serious, but rare, adverse effects reported include tachycardia and edema.[15]

Pruritus after discontinuation of cetirizine

Discontinuing cetirizine after prolonged use (typically, use beyond six months) may result in pruritus (generalized itchiness).[16] [17] [18]

The United States Food and Drug Administration (FDA) analyzed cases of pruritus after stopping cetirizine in the FDA Adverse Event Reporting System (FAERS) database and medical literature through 24 April 2017. Their report noted that some patients indicated the itchiness impacted their ability to work, sleep or perform normal daily activities.[19]

No specific schedule for weaning is currently provided in the drug information for cetirizine.[20]

Pharmacology

Pharmacodynamics

Cetirizine acts as a highly selective antagonist of the histamine H1 receptor.[21] The Ki values for the H1 receptor are approximately 6 nM for cetirizine, 3 nM for levocetirizine, and 100 nM for dextrocetirizine, indicating that the levorotatory enantiomer is the main active form. Cetirizine has 600-fold or greater selectivity for the H1 receptor over a wide variety of other sites, including muscarinic acetylcholine, serotonin, dopamine, and α-adrenergic receptors, among many others. The drug shows 20,000-fold or greater selectivity for the H1 receptor over the five muscarinic acetylcholine receptors, and hence does not exhibit anticholinergic effects.[22] [23] It shows negligible inhibition of the hERG channel (> 30 μM)[24] and no cardiotoxicity has been observed with cetirizine at doses of up to 60 mg/day, six times the normal recommended dose and the highest dose of cetirizine that has been studied in healthy subjects.[25]

Cetirizine crosses the blood–brain barrier only slightly, and for this reason, produces minimal sedation compared to many other antihistamines.[26] A positron emission tomography (PET) study found that brain occupancy of the H1 receptor was 12.6% for 10 mg cetirizine, 25.2% for 20 mg cetirizine, and 67.6% for 30 mg hydroxyzine.[27] (A 10 mg dose of cetirizine equals about a 30 mg dose of hydroxyzine in terms of peripheral antihistamine effect.)[28] PET studies with antihistamines have found that brain H1 receptor occupancy of more than 50% is associated with a high prevalence of somnolence and cognitive decline, whereas brain H1 receptor occupancy of less than 20% is considered to be non-sedative.[29] In accordance, H1 receptor occupancy correlated well with subjective sleepiness for 30 mg hydroxyzine but there was no correlation for 10 or 20 mg cetirizine. As such, brain penetration and brain H1 receptor occupancy by cetirizine are dose-dependent, and in accordance, while cetirizine at doses of 5 to 10 mg have been reported to be non-sedating or mildly sedating, a higher dose of 20 mg has been found to induce significant drowsiness in other studies.

Cetirizine also shows anti-inflammatory properties independent of H1 receptors.[30] The effect is exhibited through suppression of the NF-κB pathway, and by regulating the release of cytokines and chemokines, thereby regulating the recruitment of inflammatory cells.[31] [32] [33] [34] [35] It has been shown to inhibit eosinophil chemotaxis and LTB4 release.[36] At a dosage of 20 mg, Boone et al. found that it inhibited the expression of VCAM-1 in patients with atopic dermatitis.

Pharmacokinetics

Absorption

Cetirizine is rapidly and extensively absorbed upon oral administration in tablet or syrup form. The oral bioavailability of cetirizine is at least 70% and of levocetirizine is at least 85%. The Tmax of cetirizine is approximately 1.0 hour regardless of formulation. The pharmacokinetics of cetirizine have been found to increase linearly with dose across a range of 5 to 60 mg. Its Cmax following a single dose has been found to be 257 ng/mL for 10 mg and 580 ng/mL for 20 mg.[37] Food has no effect on the bioavailability of cetirizine but has been found to delay the Tmax by 1.7 hours (i.e., to approximately 2.7 hours) and to decrease the Cmax by 23%.[38] Similar findings were reported for levocetirizine, which had its Tmax delayed by 1.25 hours and its Cmax decreased by about 36% when administered with a high-fat meal. Steady-state levels of cetirizine occur within 3 days and there is no accumulation of the drug with chronic administration. Following once-daily administration of 10 mg cetirizine for ten days, the mean Cmax was 311 ng/mL.[39]

Distribution

The mean plasma protein binding of cetirizine has been found to be 93 to 96% across a range of 25 to 1,000 ng/mL independent of concentration. Plasma protein binding of 88 to 96% has also been reported across multiple studies. The drug is bound to albumin with high affinity, while α1-acid glycoprotein and lipoproteins contribute much less to total plasma protein binding. The unbound or free fraction of levocetirizine has been reported to be 8%. The true volume of distribution of cetirizine is unknown but is estimated to be 0.3 to 0.45 L/kg. Cetirizine poorly and slowly crosses the blood–brain barrier, which is thought to be due to its chemical properties and its activity as a P-glycoprotein substrate.[40] [41]

Metabolism

Cetirizine is notably not metabolized by the cytochrome P450 system.[42] Because of this, it does not interact significantly with drugs that inhibit or induce cytochrome P450 enzymes such as theophylline, erythromycin, clarithromycin, cimetidine, or alcohol. Studies with cetirizine synthesized with radioactive carbon-14 show that 90% of excreted cetirizine is unchanged at 2 hours, 80% at 10 hours, and 70% at 24 hours, indicating limited and slow metabolism. While cetirizine does not undergo extensive metabolism or metabolism by the cytochrome P450 enzyme, it does undergo some metabolism by other means, the metabolic pathways of which include oxidation and conjugation. The enzymes precise enzymes responsible for transformation of cetirizine have not been identified.

Elimination

Cetirizine is eliminated approximately 70 to 85% in the urine and 10 to 13% in the feces. In total, about 60% of cetirizine eliminated in the urine is unchanged. It is eliminated in the urine via an active transport mechanism. The elimination half-life of cetirizine ranges from 6.5 to 10 hours in healthy adults, with a mean across studies of approximately 8.3 hours. The elimination half-life of cetirizine is increased in the elderly (to 12 hours), in hepatic impairment (to 14 hours), and in renal impairment (to 20 hours). Concentrations of cetirizine in the skin decline much slower than concentrations in the blood plasma. Its duration of action is at least 24 hours.

Chemistry

Cetirizine contains L- and D-stereoisomers. Chemically, levocetirizine is the active L-enantiomer of cetirizine. The drug is a member of the diphenylmethylpiperazine group of antihistamines. Analogues include cyclizine and hydroxyzine.[43]

Synthesis

The 1-(4-chlorophenylmethyl)-piperazine is alkylated with methyl (2-chloroethoxy)-acetate in the presence of sodium carbonate and xylene solvent to produce the Sn2 substitution product in 28% yield. Saponification of the acetate ester is done by refluxing with potassium hydroxide in absolute ethanol to afford a 56% yield of the potassium salt intermediate. This is then hydrolyzed with aqueous HCl and extracted to give an 81% yield of the carboxylic acid product.[44]

Availability

Cetirizine is available without a prescription.[45] In some countries, it is only available over-the-counter in packages containing seven or ten 10 mg doses.[46] [47]

Cetirizine is available as a combination medication with pseudoephedrine, a decongestant.[48] The combination is often marketed using the same brand name as the cetirizine with a "-D" suffix (for example, Zyrtec-D).[49] [50]

Cetirizine is marketed under the brand names Alatrol, Alerid, Allacan, Allercet, Alzene, Cerchio, Cetirin, Cetizin, Cetriz, Cetzine, Cezin, Cetgel, Cirrus, Histec, Histazine, Humex, Letizen, Okacet (Cipla), Piriteze, Reactine, Razene, Rigix, Sensahist (Oethmann, South Africa), Triz, Zetop, Zirtec, Zirtek, Zodac, Zyllergy, Zynor, Zyrlek, and Zyrtec (Johnson & Johnson), inter alios.[51] [52]

Notes and References

  1. Chen C . Physicochemical, pharmacological and pharmacokinetic properties of the zwitterionic antihistamines cetirizine and levocetirizine . Current Medicinal Chemistry . 15 . 21 . 2173–2191 . 2008 . 18781943 . 10.2174/092986708785747625 .
  2. Simons FE . Comparative pharmacology of H1 antihistamines: clinical relevance . The American Journal of Medicine . 113 . Suppl 9A . 38S–46S . December 2002 . 12517581 . 10.1016/s0002-9343(02)01436-5 .
  3. Slater JW, Zechnich AD, Haxby DG . Second-generation antihistamines: a comparative review . Drugs . 57 . 1 . 31–47 . January 1999 . 9951950 . 10.2165/00003495-199957010-00004 . 46984477 .
  4. Web site: Cetirizine Pregnancy and Breastfeeding Warnings . Drugs.com . 3 March 2019 . en . 6 March 2019 . https://web.archive.org/web/20190306044632/https://www.drugs.com/pregnancy/cetirizine.html . live .
  5. Web site: Cetirizine Hydrochloride Monograph for Professionals . Drugs.com . American Society of Health-System Pharmacists . 3 March 2019 . 28 August 2021 . https://web.archive.org/web/20210828025357/https://www.drugs.com/monograph/cetirizine.html . live .
  6. Zhou P, Jia Q, Wang Z, Zhao R, Zhou W . Cetirizine for the treatment of allergic diseases in children: A systematic review and meta-analysis . Frontiers in Pediatrics . 10 . 940213 . 25 August 2022 . 36090559 . 9452751 . 10.3389/fped.2022.940213 . free .
  7. US4525358A. 2-[4-(Diphenylmethyl)-1-piperazinyl]-acetic acids and their amides]. 1985-06-25. Baltes. Lannoy. Rodriguez. Eugene. Jean de. Ludovic.
  8. Book: Fischer J, Ganellin CR . Analogue-based Drug Discovery . 2006 . John Wiley & Sons . 9783527607495 . 549 . en . 19 September 2020 . 8 October 2022 . https://web.archive.org/web/20221008080257/https://books.google.com/books?id=FjKfqkaKkAAC&pg=PA549 . live .
  9. Book: ((World Health Organization)) . World Health Organization model list of essential medicines: 22nd list (2021) . 2021 . 10665/345533 . World Health Organization . World Health Organization . Geneva . WHO/MHP/HPS/EML/2021.02 . free .
  10. Book: British national formulary : BNF 76. 2018. Pharmaceutical Press. 9780857113382. 279. 76.
  11. Web site: The Top 300 of 2021 . ClinCalc . 14 January 2024 . 15 January 2024 . https://web.archive.org/web/20240115223848/https://clincalc.com/DrugStats/Top300Drugs.aspx . live .
  12. Web site: Cetirizine - Drug Usage Statistics . ClinCalc . 14 January 2024 .
  13. Book: Rang HP, Dale MM, Flower RJ, Henderson G . Rang and Dale's pharmacology. 21 January 2015 . 978-0-7020-5362-7. Eighth. [United Kingdom]. 332. 903083639.
  14. Web site: CETIRIZINE HYDROCHLORIDE. 17 October 2020. 10 October 2022. https://web.archive.org/web/20221010052416/https://www.nice.org.uk/bnf-uk-only. live.
  15. Web site: Zyrtec Side Effects. drugs.com. 21 August 2015. 23 July 2019. https://web.archive.org/web/20190723081747/https://www.drugs.com/sfx/zyrtec-side-effects.html. live.
  16. Ekhart C, van der Horst P, van Hunsel F . Unbearable Pruritus After Withdrawal of (Levo)cetirizine . Drug Safety: Case Reports . 3 . 1 . 16 . December 2016 . 27889900 . 5124431 . 10.1007/s40800-016-0041-9 .
  17. Web site: Cetirizine (Zyrtec) Withdrawal & Unbearable Itching . https://web.archive.org/web/20130814045348/http://www.peoplespharmacy.com/2013/05/06/cetirizine-zyrtec-withdrawal-unbearable-itching/. dead. 14 August 2013. People's Pharmacy. 9 September 2017.
  18. Web site: addicted to zyrtec?. MedHelp. 9 September 2017. 16 September 2017. https://web.archive.org/web/20170916010832/http://www.medhelp.org/posts/Allergy/addicted-to-zyrtec/show/600862. live.
  19. Chung AH, La Grenade L, Harinstein LM . Pruritus after discontinuation of cetirizine . Therapeutic Advances in Drug Safety . 10 . 2042098619859996 . 2019 . 31308927 . 6613055 . 10.1177/2042098619859996 .
  20. Web site: Borst H . 18 May 2023 . Did you know stopping Zyrtec can cause withdrawal? . 23 July 2023 . The Checkup . en-US.
  21. Portnoy JM, Dinakar C . Review of cetirizine hydrochloride for the treatment of allergic disorders . Expert Opinion on Pharmacotherapy . 5 . 1 . 125–135 . January 2004 . 14680442 . 10.1517/14656566.5.1.125 . 28946859 .
  22. Zhang L, Cheng L, Hong J . The clinical use of cetirizine in the treatment of allergic rhinitis . Pharmacology . 92 . 1–2 . 14–25 . 2013 . 23867423 . 10.1159/000351843 . doi . free .
  23. Orzechowski RF, Currie DS, Valancius CA . Comparative anticholinergic activities of 10 histamine H1 receptor antagonists in two functional models . European Journal of Pharmacology . 506 . 3 . 257–264 . January 2005 . 15627436 . 10.1016/j.ejphar.2004.11.006 .
  24. Taglialatela M, Pannaccione A, Castaldo P, Giorgio G, Zhou Z, January CT, Genovese A, Marone G, Annunziato L . 6 . Molecular basis for the lack of HERG K+ channel block-related cardiotoxicity by the H1 receptor blocker cetirizine compared with other second-generation antihistamines . Molecular Pharmacology . 54 . 1 . 113–121 . July 1998 . 9658196 . 10.1124/mol.54.1.113 .
  25. Hulhoven R, Rosillon D, Letiexhe M, Meeus MA, Daoust A, Stockis A . Levocetirizine does not prolong the QT/QTc interval in healthy subjects: results from a thorough QT study . European Journal of Clinical Pharmacology . 63 . 11 . 1011–1017 . November 2007 . 17891537 . 10.1007/s00228-007-0366-5 . The equivalent dose of 60 mg cetirizine is also the highest dose ever administered in healthy subjects [13]. . 36218027 .
  26. Gupta A, Chatelain P, Massingham R, Jonsson EN, Hammarlund-Udenaes M . Brain distribution of cetirizine enantiomers: comparison of three different tissue-to-plasma partition coefficients: K(p), K(p,u), and K(p,uu) . Drug Metabolism and Disposition . 34 . 2 . 318–323 . February 2006 . 16303872 . 10.1124/dmd.105.007211 . 9111905 .
  27. Tashiro M, Kato M, Miyake M, Watanuki S, Funaki Y, Ishikawa Y, Iwata R, Yanai K . 6 . Dose dependency of brain histamine H(1) receptor occupancy following oral administration of cetirizine hydrochloride measured using PET with [11C]doxepin . Human Psychopharmacology . 24 . 7 . 540–548 . October 2009 . 19697300 . 10.1002/hup.1051 . 5596000 .
  28. van den Elzen MT, van Os-Medendorp H, van den Brink I, van den Hurk K, Kouznetsova OI, Lokin AS, Laheij-de Boer AM, Röckmann H, Bruijnzeel-Koomen CA, Knulst AC . 6 . Effectiveness and safety of antihistamines up to fourfold or higher in treatment of chronic spontaneous urticaria . Clinical and Translational Allergy . 7 . 4 . 2017 . 28289538 . 5309999 . 10.1186/s13601-017-0141-3 . [...] 30 mg of hydroxyzine equals about 10 mg cetirizine [11] [...] . free .
  29. Yanai K, Tashiro M . The physiological and pathophysiological roles of neuronal histamine: an insight from human positron emission tomography studies . Pharmacology & Therapeutics . 113 . 1 . 1–15 . January 2007 . 16890992 . 10.1016/j.pharmthera.2006.06.008 .
  30. Köller M, Hilger RA, Rihoux JP, König W . Cetirizine exerts anti-inflammatory effects on human neutrophils . International Archives of Allergy and Immunology . 110 . 1 . 52–56 . May 1996 . 8645978 . 10.1159/000237310 .
  31. Bielory L, Lien KW, Bigelsen S . Efficacy and tolerability of newer antihistamines in the treatment of allergic conjunctivitis . Drugs . 65 . 2 . 215–228 . 2005 . 15631542 . 10.2165/00003495-200565020-00004 . 46791611 .
  32. Walsh GM . The anti-inflammatory effects of cetirizine . Clinical and Experimental Allergy . 24 . 1 . 81–85 . January 1994 . 8156449 . 10.1111/j.1365-2222.1994.tb00921.x . 32269456 .
  33. Gelfand EW, Appajosyula S, Meeves S . Anti-inflammatory activity of H1-receptor antagonists: review of recent experimental research . Current Medical Research and Opinion . 20 . 1 . 73–81 . January 2004 . 14741075 . 10.1185/030079903125002586 . 20451677 .
  34. Fumagalli F, Baiardini I, Pasquali M, Compalati E, Guerra L, Massacane P, Canonica GW . Antihistamines: do they work? Further well-controlled trials involving larger samples are needed . Allergy . 59 . Suppl 78 . 74–77 . August 2004 . 15245363 . 10.1111/j.1398-9995.2004.00573.x . 39936983 .
  35. Grob JJ, Castelain M, Richard MA, Bonniol JP, Béraud V, Adhoute H, Guillou N, Bonerandi JJ . 6 . Antiinflammatory properties of cetirizine in a human contact dermatitis model. Clinical evaluation of patch tests is not hampered by antihistamines . Acta Dermato-Venereologica . 78 . 3 . 194–197 . May 1998 . 9602225 . 10.1080/000155598441512 . doi . free .
  36. Boone M, Lespagnard L, Renard N, Song M, Rihoux JP . Adhesion molecule profiles in atopic dermatitis vs. allergic contact dermatitis: pharmacological modulation by cetirizine . Journal of the European Academy of Dermatology and Venereology . 14 . 4 . 263–266 . July 2000 . 11204513 . 10.1046/j.1468-3083.2000.00017.x . 24026684 .
  37. Simons FE, Simons KJ . Clinical pharmacology of new histamine H1 receptor antagonists . Clinical Pharmacokinetics . 36 . 5 . 329–352 . May 1999 . 10384858 . 10.2165/00003088-199936050-00003 . 21360079 .
  38. Paśko P, Rodacki T, Domagała-Rodacka R, Palimonka K, Marcinkowska M, Owczarek D . Second generation H1 - antihistamines interaction with food and alcohol-A systematic review . Biomedicine & Pharmacotherapy . 93 . 27–39 . September 2017 . 28622592 . 10.1016/j.biopha.2017.06.008 .
  39. Web site: Zyrtec prescribing information . May 2006 . 19 November 2009 . dead . https://web.archive.org/web/20100104143424/http://www.pfizer.com/files/products/uspi_zyrtec.pdf . 4 January 2010 .
  40. Hu Y, Sieck DE, Hsu WH . Why are second-generation H1-antihistamines minimally sedating? . European Journal of Pharmacology . 765 . 100–106 . October 2015 . 26291661 . 10.1016/j.ejphar.2015.08.016 .
  41. Conen S, Theunissen EL, Vermeeren A, van Ruitenbeek P, Stiers P, Mehta MA, Toennes SW, Ramaekers JG . 6 . The role of P-glycoprotein in CNS antihistamine effects . Psychopharmacology . 229 . 1 . 9–19 . September 2013 . 23564211 . 10.1007/s00213-013-3075-z . 10416220 .
  42. Book: Mahmoudi M . Allergy and Asthma: Practical Diagnosis and Management. 2 June 2016. Springer. 978-3-319-30835-7. 574–.
  43. Web site: PubChem . Cetirizine . 4 April 2022 . U.S. Naionatl Library of Medicine .
  44. Reiter J, Trinka P, Bartha FL, Pongó L, Volk B, Simig G . 20 July 2012 . New Manufacturing Procedure of Cetirizine . Organic Process Research & Development . en . 16 . 7 . 1279–1282 . 10.1021/op300009y . 1083-6160.
  45. Web site: Cetirizine: Clinical Review . U.S. Food and Drug Administration . 11 September 2016 .
  46. Aaronson DW . Evaluation of cetirizine in patients with allergic rhinitis and perennial asthma . Annals of Allergy, Asthma & Immunology . 76 . 5 . 440–446 . May 1996 . 8630718 . 10.1016/s1081-1206(10)63461-8 .
  47. Jobst S, van den Wijngaart W, Schubert A, van de Venne H . Assessment of the efficacy and safety of three dose levels of cetirizine given once daily in children with perennial allergic rhinitis . Allergy . 49 . 8 . 598–604 . September 1994 . 7653736 . 10.1111/j.1398-9995.1994.tb00125.x . 46312788 .
  48. Wellington K, Jarvis B . Cetirizine/pseudoephedrine . Drugs . 61 . 15 . 2231–2240 . 2001 . 11772135 . 10.2165/00003495-200161150-00009 . 263997602 .
  49. Nathan RA, Finn AF, LaForce C, Ratner P, Chapman D, de Guia EC, Hewlett D, Kramer B . 6 . Comparison of cetirizine-pseudoephedrine and placebo in patients with seasonal allergic rhinitis and concomitant mild-to-moderate asthma: randomized, double-blind study . Annals of Allergy, Asthma & Immunology . 97 . 3 . 389–396 . September 2006 . 17042147 . 10.1016/S1081-1206(10)60806-X .
  50. Web site: Antihistamine/Decongestant Combination (Oral Route) Description and Brand Names . Mayo Clinic . 7 February 2023 . 23 February 2023.
  51. Web site: 30 October 2018 . Cetirizine: antihistamine that relieves allergy symptoms . 23 October 2023 . nhs.uk . en.
  52. Web site: Protriptyline . AHFS Patient Medication Information [Internet] . Bethesda (MD) . American Society of Health-System Pharmacists, Inc. . 2019 . Medlineplus .

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cetirizine".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.