This is a popular glaucoma eye drop. Xalatan was the first prostaglandin drop available and is considered by many doctors the best initial treatment for glaucoma given its action and easy dosing. This drop is taken only once a day, usually at bedtime. This drug is now available as the generic drop latanoprost. Alternative drops in the same drug class include Travatan, Lumigan, and preservative-free Zioptan.