Levocabastin (Levocabastine Hydrochloride)

• Levocabastine is an H1‑receptor antagonist used to manage allergic conditions affecting the eye and nasal mucosa.
• Allergic conjunctivitis: reduces ocular itching, redness and tearing caused by histamine release.
• Allergic rhinitis: relieves nasal itching, sneezing and rhinorrhea associated with seasonal or perennial allergies.
• Seasonal allergic rhinoconjunctivitis: provides combined relief of nasal and ocular symptoms during pollen season.

• Levocabastine Hydrochloride acts as a selective antagonist at histamine H1 receptors located on mast cells, sensory nerves and vascular endothelium in the conjunctiva and nasal mucosa. By competitively blocking these receptors, it prevents histamine‑induced vasodilation, increased vascular permeability and sensory nerve activation, thereby reducing itching, redness, swelling and secretions associated with allergic responses. The blockade is reversible and does not affect other histamine receptor subtypes.

Levocabastine may cause local and systemic adverse reactions, most of which are mild and transient.

Common Side Effects

• Burning or stinging sensation in the eye or nasal passages.
• Transient blurred vision after ocular application.
• Mild nasal irritation or dryness.
• Headache.
• Unpleasant taste sensation.

Serious or Rare Side Effects

• Severe allergic reaction (anaphylaxis) requiring immediate medical attention.
• Ocular inflammation or worsening of pre‑existing eye disease.
• Significant nasal bleeding or epistaxis.

When using Levocabastine, consider the following precautions:

• Pregnancy: consult a healthcare provider before use as safety data are limited.
• Breastfeeding: avoid unless the potential benefit justifies the potential risk to the infant.
• Concomitant ocular disease: use with caution in patients with corneal ulcer, severe dry eye, or active infection.
• Age: safety has not been established in children younger than two years.
• Drug interactions: review concomitant antihistamines or MAO inhibitors for additive effects.
• Store at below 25°C: keep in the original container, protect from light and moisture.

Levocabastine may interact with other medicines; monitor the following:

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): concurrent use may increase the risk of hypertensive reactions.
• Other H1‑receptor antagonists: combined use can lead to excessive anticholinergic effects.

Moderate Interactions (Monitor Closely)

• Alcohol: may enhance drowsiness or sedation.
• Systemic antihistamines: additive antihistaminic effects may increase dryness.
• Other ocular decongestants or drops: may increase local irritation or pressure changes.