loratadine (Claritin)
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Introduction
Tradename: Claritin. (now over the counter {2002}[5][6])
Indications
- treatment of allergies
- seasonal allergic rhinitis
- safe during pregnancy
Dosage
- 10 mg PO QD
- 10 mg PO QOD if creatinine clearance < 30 mL/min
- 10 mg PO QOD with hepatic failure
Tabs: 10 mg. Claritin-D: 10 mg loratadine/240 mg pseudoephedrine sulfate. 1 tab PO QD. Claritin Reditabs: long-acting, rapidly disintegrating micronized form 10 mg PO QD Phamacokinetics:
- onset of action: 3 hours[7]
- take on an empty stomach
- peak plasma concentrations are delayed 1 hour when taken with food
- plasma concentrations increased by 75% in patient with chronic renal failure
- metabolized by cyt P450 2D6 & cyt P450 3A4
- elimination 1/2life 12-15 hours, 18 hours (geriatrics)
- dose adjustment with liver & renal failure
Adverse effects
- dry mouth
- drowsiness
- ataxia
- headache
- dizziness
- does not cause prolongation of QT interval
Drug interactions
- additive effects with other CNS depressants
- MAO inhibitors increase anticholinergic effects
- any pharmaceutical agent that inhibits cyt P450 2D6 or cyt P450 3A4 may increase levels of loratadine
- any drug that induces cyt P450 3A4 may diminish levels of loratadine
Laboratory
Mechanism of action
- H1 receptor antagonist (long-acting non-sedating antihistamine)
More general terms
Additional terms
- cytochrome P450 2D6 (cytochrome P450 2D, cytochrome P450 DB1, debrisoquine-4-hydroxylase, CYP2D6)
- cytochrome P450 3A4 (cytochrome P450 C3, nifedipine oxidase, P450-PCN1, NF-25, CYP3A4)
Component of
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Schering Corporation, prescribing information, 12/98
- ↑ Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ Prescriber's Letter 13(3): 2006 Cytochrome P450 drug interactions Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=220233&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 5.0 5.1 Prescriber's Letter 9(4):24 2002
- ↑ 6.0 6.1 Prescriber's Letter 9(12):69 2002
- ↑ 7.0 7.1 Prescriber's Letter 15(7): 2008 Comparison of Antihistamines Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=240707&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ Deprecated Reference