(-)-Cetirizine

388.89

388.89

1312995-182-4

6U5EA9RT2O

DTXSID60156294

C66008

R06AE09|R - Respiratory system

29335990

53

2.16

white powder

1.237±0.06 g/cm3(Predicted)

205-208°C (dec.)

542.1±45.0 °C(Predicted)

281.6±28.7 °C

1.589

-20°C Freezer

1.39E-12mmHg at 25°C

P264, P270, P301+P312, P330, P501

H302

Patients experiencing an overdose may present with drowsiness. Children may become agitated and restless before drowsiness. Patients should be treated with supportive measures. Dialysis will not assist in removing the drug from the body. The maximal nonlethal dose in mice and rats is 240mg/kg.

Cetirizine and levocetirizine use are not generally associated with liver enzyme elevations, but have been linked to rare instances of clinically apparent liver injury. In published reports, the time to onset varied widely, from 1 to 40 weeks and the pattern of injury ranged from cholestatic hepatitis to hepatocellular jaundice. The reported cases were mild to moderate in severity and self-limited in course with rapid recovery after stopping the medication. Immunoallergic and autoimmune features were rare, but recurrence of acute liver injury upon reexposure to cetirizine has been described.

Plasma protein binding of levocetirizine was on average 96.1% 1 hour post dose and 91.9% 6 hours post dose.

Levocetirizine is indicated to treat symptoms of perennial allergic rhinitis and uncomplicated skin manifestations of chronic idiopathic urticaria. It is also used over the counter for a variety of mild allergy symptoms.|FDA Label|Treatment of allergic rhinitis

Cetirizine and its enantiomer levocetirizine are second generation antihistamines that are used for the treatment of allergic rhinitis, angioedema and chronic urticaria. Cetirizine and levocetirizine have been linked to rare, isolated instances of clinically apparent acute liver injury.

Antihistamines

Cetirizine has known transformation products that include 1-[(4-Chlorophenyl)phenylmethyl]piperazine, 4-Chlorobenzophenone, and Cetirizine N-oxide.

Levocetirizine is a second generation histamine H₁ antagonist used to treat various allergic symptoms. It has a long duration of action as it is generally taken once daily, and a wide therapeutic window as animal studies show the maximal nonlethal dose is over 100x a normal dose. Patients are cautioned to avoid tasks that require complete alertness, avoid alertness, and use caution in patients with factors predisposing urinary retention.

A class of non-sedating drugs that bind to but do not activate histamine receptors (DRUG INVERSE AGONISM), thereby blocking the actions of histamine or histamine agonists. These antihistamines represent a heterogenous group of compounds with differing chemical structures, adverse effects, distribution, and metabolism. Compared to the early (first generation) antihistamines, these non-sedating antihistamines have greater receptor specificity, lower penetration of BLOOD-BRAIN BARRIER, and are less likely to cause drowsiness or psychomotor impairment. (See all compounds classified as Histamine H1 Antagonists, Non-Sedating.)

Following a 5mg oral dose of levocetirizine, a C_max of 0.27±0.04µg/mL with a T_max of 0.75±0.50h. The AUC of levocetirizine is 2.31±0.50µg\*h/mL. Taking levocetirizine with food does not affect the AUC but delays T_max by 1.25 hours and lowers C_max by 36%.|168 hours post dose an average of 85.4% of a radiolabeled dose was recovered with an average of 80.8% in the urine and 9.5% in the feces. In the urine, 77% of the dose was recovered as unchanged drug, 0.5% as the M8 and M9 metabolites, 0.4% as the M10a metabolite, 0.4% as the M10b metabolite, 0.3% as the M3 metabolite, 0.3% as the M4 and M5 metabolite, 0.2% as the M2 metabolite, and 0.1% as the M1 metabolite. In the feces, 9.0% of the dose was recovered as unchanged drug, 1.0% as the M4 and M5 metabolite, and 0.1% as the M1 metabolite.|The volume of distribution of levocetirizine is 0.33±0.02L/kg.|The average clearance of levocetirizine is 0.57±0.18mL/min/kg.

Levocetirizine is poorly metabolized with 85.8% of an oral dose being excreted as the unchanged drug. Levocetirizine can be metabolized to a dihydrodiol (M2), an N-oxide (M3), a hydroxymethoxy derivative (M4), a hydroxy derivative (M5), an O-dealkylated derivative (M6), a taurine conjugate (M8), and an N-dealkylated and aromatic hydroxylated derivative (M9). The M5 metabolite can be glucuronidated to form the M1 metabolite and the M9 metabolite can form 4-chloro-4'-hydroxybenzhydryl mercapturates (M10a and M10b).

The average half life of levocetirizine is 7.05±1.54 hours.

Levocetirizine selectively inhibits histamine H₁ receptors. This action prevents histamine from activating this receptor and causing effects like smooth muscle contraction, increased permeability of vascular endothelium, histidine uptake in basophils, stimulation of cough receptors, and stimulation of flare responses in the nervous system.

(2-(4-((R)-(4-chlorophenyl)phenylmethyl)piperazin-1-yl)ethoxy)acetic acid dihydrochloride

Human Drugs -> EU pediatric investigation plans|Human Drugs -> FDA Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book) -> Active Ingredients|Pharmaceuticals -> Antihistamines