“Comprehensive Overview of Levocetirizine and Pseudoephedrine: Pharmacology, Uses, and Safety Profile”

Levocetirizine & Pseudoephedrine Combination

This combination medication includes:

1. Levocetirizine – a third-generation non-sedating antihistamine.
2. Pseudoephedrine – a sympathomimetic agent with decongestant properties.

It is commonly used to treat symptoms of allergic rhinitis, including nasal congestion, sneezing, runny nose, and itchy/watery eyes.

1. Levocetirizine

Mechanism of Action:

Levocetirizine is the R-enantiomer of cetirizine. It selectively blocks histamine H1 receptors, which prevents histamine from causing allergic symptoms like inflammation, itching, and swelling.

Pharmacokinetics:

• Onset: Within 1 hour
• Peak effect: 1–3 hours
• Half-life: ~8–10 hours
• Excretion: Mainly via urine

2. Pseudoephedrine

Mechanism of Action:

Pseudoephedrine stimulates alpha-adrenergic receptors in the nasal mucosa, leading to vasoconstriction, which reduces swelling and nasal congestion. It also has mild beta-adrenergic effects.

Pharmacokinetics:

• Onset: 15–30 minutes
• Duration: 3–6 hours
• Excretion: Unchanged in urine (pH-dependent)

Indications (Uses):

• Seasonal allergic rhinitis
• Perennial allergic rhinitis
• Nasal congestion associated with allergies or upper respiratory infections
• Sinus pressure and congestion

Dosage (Typical):

Usually available in extended-release tablet form (e.g., Levocetirizine 5 mg + Pseudoephedrine 120 mg).

Adults and children ≥12 years:

• One tablet every 12 or 24 hours, depending on the formulation.
• Not recommended for children <12 years without medical advice.

Side Effects

Levocetirizine:

• Drowsiness (rare, less than other antihistamines)
• Dry mouth
• Fatigue
• Headache
• Dizziness
• Sore throat

Pseudoephedrine:

• Insomnia
• Nervousness
• Restlessness
• Increased blood pressure
• Palpitations
• Urinary retention (especially in men with prostate enlargement)

Precautions

• Hypertension or cardiovascular disease (due to pseudoephedrine)
• Renal impairment (adjust levocetirizine dose)
• Glaucoma
• Hyperthyroidism
• Prostatic hypertrophy
• Seizure disorders

Drug Interactions

• MAO inhibitors (e.g., selegiline, phenelzine): contraindicated within 14 days due to risk of hypertensive crisis.
• Other CNS stimulants or decongestants: risk of additive side effects.
• Alcohol: may increase drowsiness or dizziness.
• Beta-blockers: may reduce effectiveness or increase hypertension risk.

Contraindications

• Hypersensitivity to either drug
• Severe hypertension or coronary artery disease (due to pseudoephedrine)
• Severe renal impairment (for levocetirizine)
• Narrow-angle glaucoma (relative contraindication)

Pregnancy and Lactation

• Pregnancy: Category B for levocetirizine; pseudoephedrine is generally avoided, especially in the first trimester due to possible risk of abdominal wall defects in infants.
• Lactation: Both drugs can pass into breast milk; caution advised.

Storage

• Store at room temperature away from moisture and heat.
• Protect from light and keep out of reach of children.