SEASONIX TABLET

Indications

• Allergic rhinitis
• Chronic idiopathic urticaria

Dosage

Children: For children aged 6 to 12 years, the usual dose is 2.5 mg once daily. For children aged 12 years and older, the usual dose is 5 mg once daily.

Adults: The usual dose is 5 mg once daily.

Mechanism of action

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.

Pharmacodynamics

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 100 times a normal dose. Patients are cautioned to avoid tasks that require complete alertness and to use caution in those with factors predisposing to urinary retention.

Pharmacokinetics

Levocetirizine is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 0.9 hours after oral administration. It has a volume of distribution of about 0.4 L/kg and is approximately 90% protein-bound. The elimination half-life is about 8 hours, and it is primarily excreted unchanged in the urine. Renal impairment may necessitate dosage adjustments.

Adverse effects

• Drowsiness
• Dry mouth
• Fatigue
• Headache
• Gastrointestinal disturbances

Precautions

• Use caution in patients with a history of urinary retention
• Patients should be advised to avoid tasks requiring full alertness

Pregnancy

The safety of levocetirizine in pregnancy has not been established. It should only be used if clearly needed.

Breast-feeding

Levocetirizine is excreted in breast milk. Caution is advised when administered to nursing women.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Tablets
• Oral solution

Mechanism of action

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.

Pharmacodynamics

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.