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Topical levocabastine protects better than sodium cromoglycate and placebo in conjunctival provocation tests
M Rimås1, N I Kjellman, L O Blychert
1Department of Pediatrics, Faculty of Health Sciences, Linköping University, Sweden.
Insights
Levocabastine significantly improved allergic conjunctivitis treatment by increasing the allergen threshold dose in children. This H1 receptor antagonist demonstrated superior efficacy compared to cromoglycate and placebo in a conjunctival provocation test.
Area of Science:
- Ophthalmology
- Allergology
- Pharmacology
Background:
- Allergic conjunctivitis is a common condition often treated with antihistamines.
- Topical H1 receptor antagonists are a key treatment modality.
- Evaluating drug efficacy through conjunctival provocation tests (CPT) is crucial.
Purpose of the Study:
- To evaluate the protective effect of levocabastine against allergic conjunctivitis.
- To compare levocabastine's efficacy with cromoglycate and placebo using CPT.
- To assess the utility of determining the allergenic threshold dose (ATD) for drug assessment.
Main Methods:
- A double-blind study involving 25 children (aged 9-17) with confirmed pollen allergy.
- Administration of levocabastine, cromoglycate, or placebo drops to the conjunctival sac.
- Conjunctival provocation test (CPT) with escalating doses of pollen extract to determine the ATD.
Main Results:
- Levocabastine pretreatment resulted in a median ATD of 32,000 BU.
- Cromoglycate and placebo groups showed significantly lower median ATDs (10,000 BU).
- Levocabastine was also more effective in reducing subjective eye itch.
Conclusions:
- Levocabastine demonstrates superior efficacy in treating allergic conjunctivitis compared to cromoglycate and placebo.
- The ATD determination via CPT is a valuable and relatively rapid method for assessing anti-allergic drugs for the eyes.
- Levocabastine offers a promising topical treatment option for allergic conjunctivitis.
Abstract:
Levocabastine is a new H1 receptor blocking antihistamine which is intended for topical use in the treatment of allergic conjunctivitis. The protective effect of the drug in conjunctival provocation test (CPT) was evaluated in a double blind study of 25 children aged 9-17 years with confirmed pollen allergy. One drop of levocabastine, cromoglycate or placebo was instilled into the conjunctival sac of both eyes. After 15 min CPT was performed, starting with 320 BU of pollen extract. The allergen dose was increased every 10 min in half 10-log steps in the right eye until a positive reaction occurred, or the top dose 320,000 BU was reached. The lowest dose resulting in a positive CPT reaction, i.e. at least 50% of the conjunctiva with erythema, was defined as the allergenic threshold dose (ATD). Pretreatment with levocabastine resulted in a median ATD of 32,000 BU, compared with 10,000 after cromoglycate (P less than 0.001) or placebo (P less than 0.01). Levocabastine was also superior in reducing subjective itch in the eyes. Determination of the ATD can be used as a relatively quick assessment of drugs intended for the treatment of allergic conjunctivitis.