Abstract: A new topical drug (ointment or eye drop) for treating glaucoma or ocular hypertension in a patient, which comprises a mixture of a nitric oxide (NO) donor such as nitrovasodilators like minoxidil, nitroglycerin, L-arginine, isosorbide dinitrate, or nitroprusside, and a cyclic guanosine 3′,5′-monophosphate (cGMP) specific phosphodiesterase type 5 (PDE5) inhibitor such as sildenafil citrate (ViagraRTM) in an ophthalmologically acceptable solution mix. In this manner there will be increased blood circulation to the optic nerve and the ocular hypotensive effect of the combined compounds is enhanced synergistically.