Latanoprost in the treatment of glaucoma and ocular hypertension.
Latanoprost (Xalatan) is a prostaglandin F(2alpha) analog prodrug which is activated when hydrolyzed in the cornea and plasma. Latanoprost reduces the intraocular pressure (IOP) by increasing uveoscleral outflow. Other locally applied medications reduce IOP either by increasing the outflow of fluid through the trabecular drainage system or by reducing the production of fluid in the eye. Latanoprost, which is used topically in the eye at the low dose of 0.005% once daily, has been shown in phase III studies carried out in Scandinavia, the U.K. and the U.S. to be capable of lowering the IOP in patients with open-angle glaucoma and ocular hypertension by 35%. This low IOP is maintained over at least a 2-year period. Latanaprost is as effective, or possible slightly more effective than timolol in its pressure reducing effects. Additional pressure reduction can be achieved by adding latanoprost to existing glaucoma medications. Because latanoprost is rapidly metabolized outside the eye, systemic side effects do not occur. Increased iris pigmentation occurs in at least 10% of hazel (but not blue or dark-eyed patients). So far no ocular problem has occurred because of the increased production of pigment which is not released from the iris. Isolated cases of cystoid macular edema have occurred, so that anyone complaining of reduction of vision while using the drug should be fully investigated.