OCULAR HYPOTENSIVE EFFECT OF TOPICAL KETANSERIN IN TIMOLOL USERS

Background: Ketanserin is a specific antagonist of 5-HT2 and 5-HT1c re ceptors. These receptors are linked to the stimulation of phosphoinosi tide metabolism and are involved in IOP controls. Orally and topically administered ketanserin reduces IOP in normotensive and glaucomatous eyes. Methods: Ketanserin 0.5% eye drops were administered to 20 patie nts with primary open-angle glaucoma in a randomised, crossover, doubl e-masked fashion to evaluate the effect of ketanserin in glaucomatous patients already receiving timolol who did not have controlled IOP (>2 1 mmHg). Mean and range of IOP curve (8.00 a.m.-8.00 p.m.), pupil diam eter, Schirmer I, basal secretion test and BUT values were recorded at baseline and after 2 weeks of topical administration of ketanserin or placebo twice daily. The alternative treatment was given 2 weeks late r and the same protocol was repeated. Results: When patients received placebo no significant variations were found in the analysed parameter s. Ketanserin significantly reduced mean IOP (19.5%) and was effective for up to 12 h without inducing variations of tear secretion or pupil diameter. No systemic side effects were observed, and no significant variations in ocular symptoms and signs were reported. Conclusion: The se results indicate that topical administration of ketanserin may be u seful to reduce IOP in patients not controlled with beta-blockers.