Indications

CTZ (Cetirizine Hydrochloride) is indicated for the relief of symptoms associated with:

• Seasonal and perennial allergic rhinitis.
• Uncomplicated skin manifestations of chronic idiopathic urticaria (hives).
• Allergen-induced asthma.

Pharmacology

Cetirizine is a potent H1​ receptor antagonist that works without significant anticholinergic or antiserotonic effects. It inhibits the early phase of the allergic reaction mediated by histamine and also reduces the migration of inflammatory cells and the release of mediators associated with the late phase of allergic reactions.

Dosage & Administration

• Oral Dosage:
  • Adults and Children 6 years and older: 1 tablet or 2 teaspoonfuls daily (or 1 teaspoonful twice daily).
  • Children 2-6 years: 1 teaspoonful once daily or 1/2 teaspoonful twice daily.
  • Children 6 months to 2 years: 1/2 teaspoonful once daily. The dose can be increased to a maximum of 1/2 teaspoonful every 12 hours for children 12-23 months.
• Injectable Dosage (Intravenous only): For acute urticaria, once every 24 hours. Administer as an IV push over 1 to 2 minutes.
  • Adults and adolescents 12 years and older: 10 mg.
  • Children 6 to 11 years: 5 mg or 10 mg, depending on symptom severity.
  • Children 6 months to 5 years: 2.5 mg.

Interaction

No clinically significant drug interactions have been found with Theophylline, Azithromycin, Pseudoephedrine, Ketoconazole, or Erythromycin.

Contraindications

CTZ is contraindicated in patients with a history of hypersensitivity to Cetirizine or Hydroxyzine.

Side Effects

The most common side effect is somnolence (drowsiness).

Pregnancy & Lactation

Cetirizine is a US FDA Pregnancy Category B drug. There are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if clearly needed. Cetirizine is known to be excreted in human milk, so caution should be exercised when administering it to a nursing woman.

Precautions & Warnings

Caution should be exercised when driving a car or operating heavy machinery due to the potential for drowsiness.

Use in Special Populations

• Hepatic or Renal Insufficiency: Total body clearance is reduced, and half-life is increased by about 2 to 3-fold in patients with mild to moderate hepatic and renal impairment. Dosage adjustments may be necessary.
• Elderly Use: The clearance is reduced in elderly patients, but only in proportion to the decrease in creatinine clearance.

Therapeutic Class

Cetirizine is a sedating anti-histamine.

Storage Conditions

Keep in a dry place away from light and heat. Keep out of the reach of children.