levocetirizine

Relief of symptoms associated with seasonal (adults and children ≥2 yrs) and perennial (adults and children ≥6 months) allergic rhinitis. Treatment of uncomplicated skin manifestations of chronic idiopathic urticaria in adults and children ≥6 months.

Adult: As hydrochloride: 5 mg daily in the evening; 2.5 mg may be adequate in some patients. Max dose: 5 mg daily.

Child: As hydrochloride: 6-11 yr: 2.5 mg once daily. Max dose: 2.5 mg daily. ≥12 yr: 5 mg once daily; 2.5 mg may be adequate is some patients. Max dose: 5 mg daily. All doses to be taken in the evening.

Special Populations: If CrCl 30-50 mL/minute, 5 mg on alternate days. If CrCl < 30 mL/minute, avoid.

End-stage renal disease (ESRD) (CrCl <10mL/min) .

Patients undergoing hemodialysis.

Pediatrics 6 months-11 yrs with renal impairment.

Lactation

Renal impairment.

Somnolence, fatigue, and asthenia reported, May impair ability to drive or operate machinery. May impair mental/physical abilities. Urinary retention reported; caution with predisposing factors of urinary retention (eg, spinal cord lesion, prostatic hyperplasia). D/C if urinary retention occurs. Caution in elderly.

Somnolence, fatigue, nasopharyngitis, dry mouth, constipation, diarrhea, cough, pyrexia, pharyngitis,epistaxis.

Avoid with alcohol and other CNS depressants because additional reductions in alertness and additional CNS performance impairment may occur. Decreased clearance with theophylline. Increased plasma area under the curve with ritonavir.

Levocetirizine, an active isomer of cetirizine, selectively inhibits histamine H₁-receptors.

Absorption: Rapid and extensive. C_max=270ng/mL (single dose), 308ng/mL (multiple doses); T_max=0.9 hr (tab), 0.5 hr (PO sol).

Distribution: V_d=0.4L/kg; plasma protein binding (91-92%); found in breast milk.

Metabolism: <14% metabolized through aromatic oxidation (via CYP isoforms), N- and O-dealkylation (via CYP3A4), and taurine conjugation pathways.

Elimination: Urine (85.4%), feces (12.9%); T_1/2=8-9 hrs.

B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women OR Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in any trimester.