Glaucoma is a multifactorial disease involving progressive optic neuropathy and altered intraocular hemodynamics; furthermore, glaucoma can cause blindness if it is left untreated. The aim of the present study, to explore effects of topical Sumatriptan, Fluoxetine and Metoclopramide on the intraocular pressure values of normal rabbits eyes and experimentally induced ocular hypertension in rabbits. Also to explore the possible local adverse effects of the tested drugs. A group of 78 rabbits were included in the present study. Induction of ocular hypertension was achieved by injection of hydroxyl propyl methylcellulose (0.25 ml) of (2% w/v) in the anterior chamber of rabbit right eyes. The parameters which had been frequently detected in both left and right eyes were: intraocular pressure, pupil diameter, light reflex, corneal reflex and conjunctival redness. Part I, the distilled water, timolol 0.5%, pilocarpine 2% and tested agents (inactive ingredients, sumatriptan 1%, fluoxetine 0.25% and metoclopramide 0.5%) were instilled to right eye 3 times daily for 7 days (except timolol instilled twice daily) in normotensive rabbits eyes. In normotensive eyes, all of Sumatriptan(1%), fluoxetine(0.25%), metoclopramide (0.5%), after instillation to right eyes they caused highly significant reduction in the mean intraocular pressure (P < 0.01), both sumatriptan (1%) and fluoxetine (0.25%) had a comparable effect when compared with timolol and pilocarpine (2%) effect (P > 0.05), while, metoclopramide (0.5%) had significant difference (0.01 < P 0.05) with timolol (0.5%) effect, but, it comparable to pilocarpine (2%) effect (P > 0.05). Part ΙΙ of the present study involved evaluation of the pilocarpine 2% and tested agents (sumatriptan 1%, fluoxetine 0.25% and metoclopramide 0.5%) were instilled to right eye 3 times daily for 10 days after the disease being induced (acute elevated of IOP). In acute ocular hypertension, all of Sumatriptan (1%), fluoxetine (0.25%) and metoclopramide (0.5%) after instillation to right eyes they caused highly significant reduction in the mean intraocular pressure (P < 0.01), both sumatriptan (1%) and fluoxetine (0.25%) had significant differences (0.01 < P 0.05) when compared to pilocarpine (2%) effect, while, metoclopramide (0.5%) had comparable to pilocarpine (2%) effect (P > 0.05). Part III of the present study involved evaluation of the timolol 0.5% and metoclopramide 0.5%, only after continuous induction of ocular hypertension, and maintain elevated of IOP for more than one month (chronic elevated of IOP), were instilled to right for 14 days. In chronic ocular hypertension, metoclopramide (0.5%) simulated timolol (0.5%) effect (P > 0.05). it caused highly significant reduction in the mean intraocular pressure (P < 0.01). The tested drugs had no change in pupil diameter (except metoclopramide produced significant difference (0.01 < P 0.05) to distilled water, but highly significant effect (P < 0.01) to pilocarpine 2%. Also there was no significant effect (P > 0.05) regarding light reflex, corneal reflex, but conjunctival redness caused highly significant effect (P < 0.01) with fluoxetine and metoclopramide.
In conclusion, each of Sumatriptan (1%), fluoxetine (0.25%), metoclopramide (0.5%) exerted a detectable ocular hypotensive effect on the normal eyes of rabbits when applied 3 times daily. A tested agents have beneficial ocular hypotensive effect on hydroxy propyl methyl cellulose induced ocular hypertensive of rabbits when each of them given topically 3 times daily.