Description

Simple

A medication used to manage allergy symptoms such as itchy eyes and runny nose.

Clinical

A second generation antihistamine used to manage the symptoms of allergic rhinitis.

Overview

Loratadine is a second generation antihistamine used to manage symptoms of allergic rhinitis.[5] A lack of sedative and CNS adverse effects make loratadine, along with other second generation antihistamines, preferable over their 1st generation counterparts in many clinical situations.[7]

Pharmacology

Indication

Loratadine is a 2nd generation antihistamine and is used to manage symptoms of allergic rhinitis, wheal formation, urticaria, and other allergic dermatologic conditions.[ Read more

Pharmacodynamic

Like other 2nd generation antihistamines, loratadine is selective for peripheral H1 receptors.[ Read more

Mechanism of action

Histamine release is a key mediator in allergic rhinitis and urticaria.[12][ Read more

Absorption

Loratadine is rapidly absorbed and achieves peak plasma concentration in 1-2 hours, while it's main metabolite achieves peak plasma concentration in 3-4 hours.[ Read more

Protein binding

97 - 99% of the loratadine is bound to plasma proteins.[17]

Volume of distribution

The volume of distribution of loratadine is 120 L/Kg.[18]

Clearance

The clearance of loratadine after single oral doses of 20 mg and 40 mg are 12 L/h/kg and 9 L/h/kg respectively.[ Read more

Half life

The elimination half life is approximately 10 hours for loratadine and 20 hours for descarboethoxyloratadine.[6]

Route of elimination

Over a 10 day period, 40% of loratadine is excreted in the urine, and 42% is eliminated in the faeces.[17]

Toxicity

Second generation antihistamines such as loratadine have very few adverse effects; however, insomnia, headache, fatigue, drowsiness and rash have been reported.[ Read more

Adverse Effects

Contraindications

  • Route:
    • Oral
  • Hypersensitivity:
    • true
  • Regions: US

Food Interactions

    Information currently not available.

Interactions

Type in a drug name to check for interaction with Loratadine
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  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
(R)-warfarin
The metabolism of (R)-warfarin can be decreased when combined with Loratadine.
(S)-Warfarin
The metabolism of (S)-Warfarin can be decreased when combined with Loratadine.
2,5-Dimethoxy-4-ethylamphetamine
2,5-Dimethoxy-4-ethylamphetamine may decrease the sedative and stimulatory activities of Loratadine.
2,5-Dimethoxy-4-ethylthioamphetamine
2,5-Dimethoxy-4-ethylthioamphetamine may decrease the sedative and stimulatory activities of Loratadine.
4-Bromo-2,5-dimethoxyamphetamine
4-Bromo-2,5-dimethoxyamphetamine may decrease the sedative and stimulatory activities of Loratadine.
Aclidinium
Aclidinium may increase the anticholinergic activities of Loratadine.
Agmatine
Agmatine may increase the anticholinergic activities of Loratadine.
Alcuronium
Alcuronium may increase the anticholinergic activities of Loratadine.
Almotriptan
The metabolism of Almotriptan can be decreased when combined with Loratadine.
Amantadine
Amantadine may increase the anticholinergic activities of Loratadine.
Aminophenazone
The metabolism of Aminophenazone can be decreased when combined with Loratadine.
Amiodarone
The risk or severity of QTc prolongation can be increased when Loratadine is combined with Amiodarone.
Amitriptyline
The metabolism of Amitriptyline can be decreased when combined with Loratadine.
Amobarbital
Amobarbital may increase the anticholinergic activities of Loratadine.
Amodiaquine
The metabolism of Amodiaquine can be decreased when combined with Loratadine.
Amoxapine
Amoxapine may increase the anticholinergic activities of Loratadine.
Amphetamine
Amphetamine may decrease the sedative and stimulatory activities of Loratadine.
Anastrozole
The metabolism of Anastrozole can be decreased when combined with Loratadine.
Anisotropine methylbromide
Anisotropine methylbromide may increase the anticholinergic activities of Loratadine.
Antipyrine
The metabolism of Antipyrine can be decreased when combined with Loratadine.
18 References
  1. 1 . See S: Desloratadine for allergic rhinitis. Am Fam Physician. 2003 Nov 15;68(10):2015-6.PubMed: 14655812
  2. 2 . Menardo JL, Horak F, Danzig MR, Czarlewski W: A review of loratadine in the treatment of patients with allergic bronchial asthma. Clin Ther. 1997 Nov-Dec;19(6):1278-93; discussion 1523-4.PubMed: 9444440
  3. 3 . Howarth PH: Histamine and asthma: an appraisal based on specific H1-receptor antagonism. Clin Exp Allergy. 1990 Aug;20 Suppl 2:31-41.PubMed: 1977506
  4. 4 . Baroody FM, Naclerio RM: Antiallergic effects of H1-receptor antagonists. Allergy. 2000;55 Suppl 64:17-27.PubMed: 11291777
  5. 5 . Tenn MW, Steacy LM, Ng CC, Ellis AK: Onset of action for loratadine tablets for the symptomatic control of seasonal allergic rhinitis in adults challenged with ragweed pollen in the Environmental Exposure Unit: a post hoc analysis of total symptom score. Allergy Asthma Clin Immunol. 2018 Jan 16;14:5. doi: 10.1186/s13223-017-0227-4. eCollection 2018.PubMed: 29371864
  6. 6 . Barenholtz HA, McLeod DC: Loratadine: a nonsedating antihistamine with once-daily dosing. DICP. 1989 Jun;23(6):445-50.PubMed: 2525847
  7. 7 . Randall KL, Hawkins CA: Antihistamines and allergy. Aust Prescr. 2018 Apr;41(2):41-45. doi: 10.18773/austprescr.2018.013. Epub 2018 Apr 3.PubMed: 29670310
  8. 8 . Church MK, Church DS: Pharmacology of antihistamines. Indian J Dermatol. 2013 May;58(3):219-24. doi: 10.4103/0019-5154.110832.PubMed: 23723474
  9. 9 . Clissold SP, Sorkin EM, Goa KL: Loratadine. A preliminary review of its pharmacodynamic properties and therapeutic efficacy. Drugs. 1989 Jan;37(1):42-57.PubMed: 2523301
  10. 10 . Ghosal A, Gupta S, Ramanathan R, Yuan Y, Lu X, Su AD, Alvarez N, Zbaida S, Chowdhury SK, Alton KB: Metabolism of loratadine and further characterization of its in vitro metabolites. Drug Metab Lett. 2009 Aug;3(3):162-70. Epub 2009 Aug 1.PubMed: 19702548
  11. 11 . Zhang YF, Chen XY, Zhong DF, Dong YM: Pharmacokinetics of loratadine and its active metabolite descarboethoxyloratadine in healthy Chinese subjects. Acta Pharmacol Sin. 2003 Jul;24(7):715-8.PubMed: 12852841
  12. 12 . Naclerio RM: The role of histamine in allergic rhinitis. J Allergy Clin Immunol. 1990 Oct;86(4 Pt 2):628-32. doi: 10.1016/s0091-6749(05)80227-1.PubMed: 1977783
  13. 13 . Obradovic T, Dobson GG, Shingaki T, Kungu T, Hidalgo IJ: Assessment of the first and second generation antihistamines brain penetration and role of P-glycoprotein. Pharm Res. 2007 Feb;24(2):318-27. doi: 10.1007/s11095-006-9149-4. Epub 2006 Dec 19.PubMed: 17180728
  14. 14 . Conen S, Theunissen EL, Vermeeren A, van Ruitenbeek P, Stiers P, Mehta MA, Toennes SW, Ramaekers JG: The role of P-glycoprotein in CNS antihistamine effects. Psychopharmacology (Berl). 2013 Sep;229(1):9-19. doi: 10.1007/s00213-013-3075-z. Epub 2013 Apr 7.PubMed: 23564211
  15. 15 . Kazmi F, Barbara JE, Yerino P, Parkinson A: A long-standing mystery solved: the formation of 3-hydroxydesloratadine is catalyzed by CYP2C8 but prior glucuronidation of desloratadine by UDP-glucuronosyltransferase 2B10 is an obligatory requirement. Drug Metab Dispos. 2015 Apr;43(4):523-33. doi: 10.1124/dmd.114.062620. Epub 2015 Jan 16.PubMed: 25595597
  16. 16 . Aratyn-Schaus Y, Ramanathan R: Advances in high-resolution MS and hepatocyte models solve a long-standing metabolism challenge: the loratadine story. Bioanalysis. 2016 Aug;8(16):1645-62. doi: 10.4155/bio-2016-0094. Epub 2016 Jul 27.PubMed: 27460981
  17. 17 . Health Canada Product Monograph: Claritin (loratadine) Link
  18. 18 . Comparative Pharmacology of the H1 Antihistamines Link