Overview
11 DESCRIPTION Levocetirizine dihydrochloride, USP the active component of levocetirizine dihydrochloride tablets, USP is an orally active H 1 -receptor antagonist. The chemical name is (R)-[2-[4-[(4-chlorophenyl) phenylmethyl]-1-piperazinyl] ethoxy] acetic acid dihydrochloride. Levocetirizine dihydrochloride is the R enantiomer of cetirizine hydrochloride, a racemic compound with antihistaminic...
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Levocetirizine, the active enantiomer of cetirizine, is an antihistamine; its principal effects are mediated via selective inhibition of H 1 receptors. The antihistaminic activity of levocetirizine has been documented in a variety of animal and human models. In vitro binding studies revealed that levocetirizine has an affinity for the human H 1 -receptor 2-fold higher than that of cetirizine (Ki = 3 nmol/L vs. 6 nmol/L, respectively). The clinical relevance of this finding is unknown. 12.2 Pharmacodynamics Studies in adult healthy subjects showed that levocetirizine at doses of 2.5 mg and 5 mg inhibited the skin wheal and flare caused by the intradermal injection of histamine.
Indications
- 1 INDICATIONS AND USAGE Levocetirizine dihydrochloride is a histamine H 1 -receptor antagonist indicated for: The treatment of the uncomplicated skin manifestations of chronic idiopathic urticaria ( 1.2 ) 1.2 Chronic Idiopathic Urticaria Levocetirizine dihydrochloride tablets are indicated for the treatment of the uncomplicated skin manifestations of chronic idiopathic urticaria in adults and children 6 years of age and older.
Common Doses
- 5 mg
- 2.5 mg
- 80 mL
- 50 mL
Dosage
2 DOSAGE AND ADMINISTRATION Levocetirizine dihydrochloride tablets are available as 5 mg breakable (scored) tablets, allowing for the administration of 2.5 mg, if needed. Levocetirizine tablets can be taken without regard to food consumption. Chronic Idiopathic Urticaria ( 2.2 ) Adults and children 12 years of age and older: 5 mg once daily in the evening Children 6 to 11 years of age: 2.5 mg once daily in the evening Renal Impairment Adjust the dose in patients 12 years of age and older with decreased renal function ( 12.3 ) 2.
Contraindications
- 4 CONTRAINDICATIONS The use of levocetirizine dihydrochloride is contraindicated in: Patients with a known hypersensitivity to levocetirizine or any of the ingredients of levocetirizine dihydrochloride tablets or to cetirizine ( 4.1 ) Patients with end-stage renal disease at less than 10 mL/min creatinine clearance or patients undergoing hemodialysis ( 4.2 ) Children 6 months to 11 years of age with renal impairment ( 4.3 ) 4.
Side Effects
- 6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Somnolence [see Warnings and Precautions (5.1) ] Urinary Retention [see Warnings and Precautions (5.2) ] Risk of New Onset Pruritus After Discontinuation of Levocetirizine dihydrochloride tablets [see Warnings and Precautions (5.3) ] The most common adverse reactions (rate ≥2% and > placebo) were somnolence, nasopharyngitis, fatigue, dry mouth, and pharyngitis in subjects 12 years of age and older, and pyrexia, somnolence, cough, and epistaxis in children 6 to 12 years of age.
Interactions
- 7 DRUG INTERACTIONS In vitro data indicate that levocetirizine is unlikely to produce pharmacokinetic interactions through inhibition or induction of liver drug-metabolizing enzymes. No in vivo drug-drug interaction studies have been performed with levocetirizine. Drug interaction studies have been performed with racemic cetirizine. 7.1 Antipyrine, Azithromycin, Cimetidine, Erythromycin, Ketoconazole, Theophylline, and Pseudoephedrine Pharmacokinetic interaction studies performed with racemic cetirizine demonstrated that cetirizine did not interact with antipyrine, pseudoephedrine,...