Efficacy of ketotifen fumarate 0.025% ophthalmic solution compared with placebo in the conjunctival allergen challenge model.
BACKGROUND
Ketotifen fumarate blocks histamine1 (H1) receptors, stabilizes mast cells, and acts as an eosinophil inhibitor (decreases chemotaxis and activation of eosinophils).


OBJECTIVE
To assess the efficacy of ketotifen 0.025% ophthalmic solution in the prevention of symptoms of allergic conjunctivitis, using the conjunctival allergen challenge model.


METHODS
This was a single-center, double-masked, randomized, placebo-controlled, contralateral-eye comparison, allergen challenge trial conducted in the United States. Subjects were randomized to receive ketotifen 0.025% in one eye and placebo in the other. At visits 1 and 2, allergen challenges were performed to determine the allergen concentration eliciting a qualifying reaction for each subject. At the 3 subsequent visits, subjects received 1 drop of ketotifen 0.025% ophthalmic solution in one eye and vehicle solution as placebo in the other eye 15 minutes (visit 3), 6 hours (visit 4), and 8 hours (visit 5) before allergen challenge. The primary efficacy measure was the subject's rating of itching at 3, 7, and 10 minutes after challenge.


RESULTS
Of the 89 subjects randomly assigned to masked trial medication at visit 3, 72 completed the study. At visits 3, 4, and 5, mean itching scores were significantly better for ketotifen-treated eyes at all postchallenge time points, compared with placebo (P<.001). Also at visits 3, 4, and 5, ketotifen was statistically superior to placebo in reducing ocular hyperemia at all postchallenge time points (P<.05).


CONCLUSIONS
Ketotifen was safe and statistically effective in reducing ocular itching and hyperemia associated with allergic conjunctivitis. Ketotifen's rapid onset of action (within 15 minutes) and extended duration of action (at least 8 hours) make it a valuable treatment for allergic conjunctivitis.
Abelson
Mark B
MB
Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, MA, USA. mabelson@oraclinical.com
Chapin
Matthew J
MJ
Kapik
Barry M
BM
Shams
Naveed B K
NB
D000328:Adult; D000368:Aged; D000485:Allergens / Q000009:adverse effects; D018926:Anti-Allergic Agents / Q000008:administration & dosage*; D003228:Conjunctiva / Q000098:blood supply / Q000187:drug effects; D003233:Conjunctivitis, Allergic / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D006634:Histamine H1 Antagonists / Q000008:administration & dosage*; D006801:Humans; D006940:Hyperemia / Q000517:prevention & control; D007665:Ketotifen / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009883:Ophthalmic Solutions; D011537:Pruritus / Q000517:prevention & control; D012449:Safety
D000485:Allergens; D018926:Anti-Allergic Agents; D006634:Histamine H1 Antagonists; D009883:Ophthalmic Solutions; D007665:Ketotifen