The anti-allergic effects of a cromolyn sodium-chlorpheniramine combination compared to ketotifen in the conjunctival allergen challenge model.
OBJECTIVE
To compare the inhibitory effects of a topical combination product, cromolyn sodium (DSCG) 4% with the antihistamine, chlorpheniramine, with those of topical ketotifen 0.05% on the clinical allergic reaction induced by the conjunctival allergen challenge (CAC).


METHODS
Ten allergic but non-active patients were challenged in both eyes with increasing doses of specific allergen to obtain a positive bilateral reaction (visit 1). They were then rechallenged after 1 week to confirm the allergic threshold dose response (visit 2). After 2 weeks, a third CAC was performed bilaterally 30 minutes after topical application of DSCG-chlorpheniramine in one eye and ketotifen in the contralateral eye in a double-masked fashion (visit 3). Clinical signs and symptoms were registered 5, 10, 15, and 20 minutes after challenge using the standard scoring system. Tear cytology was performed 30 minutes after challenge.


RESULTS
Comparing the two drug effects at visit 3, DSCG-chlorpheniramine was shown to be superior to ketotifen at all time points for itching (p < 0.01) and at 5 minutes for redness (p < 0.01). For the total signs score, DSCG-chlorpheniramine was shown to be superior to ketotifen at all time points (p < 0.01), and at 10 and 15 minutes for the total symptoms score (p < 0.05). Compared to visit 2, DSCG-chlorpheniramine significantly lowered itching (p < 0.001) and redness (p < 0.05) at 5, 10, 15, and 20 minutes after challenge. Ketotifen significantly lowered itching at 5 and 10 minutes (p < 0.001) and redness at 5, 10, and 15 minutes (p < 0.05). Both drugs reduced the total number of cells evaluated by tear cytology during the early-phase reaction (p < 0.05).


CONCLUSIONS
DSCG-chlorpheniramine was found to be more effective than ketotifen at preventing itching and redness in the CAC model.
Leonardi
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Department of Neuroscience, Ophthalmology and Ocular Inflammation Unit, University of Padova, Italy. andrea.leonardi@unipd.it
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D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000009:adverse effects; D018926:Anti-Allergic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D002744:Chlorpheniramine / Q000008:administration & dosage / Q000627:therapeutic use*; D003233:Conjunctivitis, Allergic / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D004205:Cromolyn Sodium / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D007665:Ketotifen / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009883:Ophthalmic Solutions; D011058:Pollen / Q000009:adverse effects
D000485:Allergens; D018926:Anti-Allergic Agents; D006634:Histamine H1 Antagonists; D009883:Ophthalmic Solutions; D002744:Chlorpheniramine; D004205:Cromolyn Sodium; D007665:Ketotifen