Cetirizine

Oral
Allergic conditions

CrCl (mL/min)	Dosage
<10	Contraindicated.
<30	5 mg every other day.
30-49	5 mg once daily.
50-79	Same as adult dose.

May be taken with or without food.

Severe renal impairment.

Patients with increased risk of urinary retention (e.g. spinal cord lesion, prostatic hyperplasia), epileptic patients and patients at risk of convulsions. Hepatic and mild to moderate renal impairment. Children. Pregnancy and lactation.

Cardiac disorders: Tachycardia.
Gastrointestinal disorders: Abdominal pain, dry mouth, nausea, diarrhea, vomiting.
General disorders and administration site conditions: Fatigue, asthenia, malaise, oedema.
Nervous system disorders: Dizziness, headache, convulsions, agitation.
Psychiatric disorders: Somnolence, aggression, confusion, depression, hallucination, insomnia, epistaxis, bronchospasm.
Respiratory, thoracic and mediastinal disorders: Pharyngitis, rhinitis.
Skin and subcutaneous tissue disorders: Pruritus, rash, urticaria.

This drug may cause CNS depression (e.g. somnolence), if affected, do not drive or operate machinery.

Monitor relief of symptoms, sedation and anticholinergic effects.

Symptoms: Confusion, diarrhoea, dizziness, fatigue, headache, malaise, mydriasis, pruritus, restlessness, sedation, somnolence, stupor, tachycardia, tremor, urinary retention. Management: Symptomatic and supportive treatment. Gastric lavage may be performed following early ingestion.

Additive CNS depression when administered concomitantly with other CNS depressants (e.g. sedatives, tranquilisers).

Decreased rate of absorption with food. May enhance the CNS depressant effect with alcohol.

May cause false-positive serum TCA screen. May suppress the wheal and flare reactions to skin test antigens.

Description: Cetirizine, a piperazine derivative and metabolite of hydroxyzine, is an antihistamine which competitively and selectively inhibits H₁ receptors in the gastrointestinal tract, blood vessels, and respiratory tract.
Onset: Suppression of skin wheal and flare: 0.7 hours.
Duration: Suppression of skin wheal and flare: ≥24 hours.
Pharmacokinetics:
Absorption: Rapidly absorbed from gastrointestinal tract. Decreased rate of absorption with food. Time to peak plasma concentration: Approx 1 hour
Distribution: Enters breast milk. Volume of distribution: 0.56 L/kg. Plasma protein binding: 93%
Metabolism: Metabolised limitedly in the liver.
Excretion: Mainly via urine (50% as unchanged drug), as faeces (10%). Elimination half-life: 10 hours.

Source: National Center for Biotechnology Information. PubChem Database. Cetirizine, CID=2678, https://pubchem.ncbi.nlm.nih.gov/compound/Cetirizine (accessed on Jan. 21, 2020)

Store between 20-25°C

Antihistamines & Antiallergics

R06AE07 - cetirizine ; Belongs to the class of piperazine derivatives used as systemic antihistamines.

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Cetirizine Hydrochloride (Allergy) Tablet (NorthStar Rx LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 14/02/2019.

Cetirizine Hydrochloride (Caraco Pharmaceutical Laboratories, Ltd.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 21/01/2014.

Joint Formulary Committee. Cetirizine Hydrochloride. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 14/02/2019.

McEvoy GK, Snow EK, Miller J et al (eds). Cetirizine Hydrochloride. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 21/01/2014.