[Comparison of three antiallergic eyedrops in a specific conjunctival provocation test: mequitazine, levocabastine and dexamethasone]

Abstract

Purpose: In order to assess the efficacy of an antihistaminic eye drop containing 0.05% mequitazine in the prevention of allergy induced by a conjunctival provocation test, a double-masked, randomized, intraindividual study compared this eye drop to 0.05% levocabastine and 0.1% dexamethasone eye drops in 24 subjects allergic to grass pollen.

Method: During the first phase of treatment, randomized subjects received one drop of dexamethasone in one eye and one drop of either mequitazine or levocabastine in the fellow eye. During the second phase of treatment, they were given one drop of dexamethasone in the same eye as previously, and one drop of the treatment that had not been given during the first phase (levocabastine or mequitazine) in the fellow eye. Fifteen minutes after each instillation phase, a conjunctival provocation test was performed. Hyperemia, itching, tearing, chemosis and palpebral edema were the five signs or symptoms taken into account to assess the treatment efficacy. Their intensity was evaluated 3, 5 and 10 min after the conjunctival provocation test. The primary efficacy criterion was the global score obtained by measuring hyperemia and itching intensity.

Results: The score was reduced significantly more (p < 0.0001) for the eyes treated with mequitazine or levocabastine than for those treated with dexamethasone at all evaluation times. The difference was also significant for hyperemia (p < 0.001), itching (p < 0.001), and tearing (p < 0.05). The tolerability of the three eyedrops was satisfactory.

Conclusion: Mequitazine and levocabastine were safe and significantly more effective than dexamethasone in preventing the allergic response induced by a conjunctival provocation test when they were instilled 15 min before contact with the allergen.