Increased ocular hypertension is one of the main characteristics of glaucoma. Monatepil belongs to a class of calcium channel blockers with special characteristic of α1-adrenergic receptor blocking effect. Calcium channel blockers and α1-adrenergic receptor blocker act as antihypertensive agents.Monatepil has been studied for its effect on ocular hypertension in experimental glaucoma and for its mechanism of action for effect in glaucoma.After pretreatment with topical monatepil (1%), 5% dextrose has been administered intravenously through marginal ear vein in healthy New Zealand white rabbits. Pilocarpine (1%) was used as the reference standard. Freshly prepared 50 units of α-chymotrypsin was injected in the posterior chamber of the eye to induce chronic model of glaucoma. After achievement of steady ocular hypertension, single dose treatment with monatepil (1%) and pilocarpine (1%) was given. To find possible mechanism of action, interaction of monatepil with pilocarpine and indomethacin has been studied.Topical administration of monatepil prevented acute increase in intraocular pressure. Monatepil (1%) and pilocarpine (1%) produced a significant decrease in intraocular pressure in α-chymotrypsin induced chronic ocular hypertensive rabbits. Indomethacin (1%) and pilocarpine (1%) pretreatment did not alter intraocular pressure lowering effect of monatepil.Monatepil give beneficial effect in ocular hypertension by enhancement of aqueous humor outflow.