Latanoprost (pronounced la-TA-noe-prost) ophthalmic solution is a topical medication used for controlling the progression of glaucoma or ocular hypertension by reducing intraocular pressure. It is a prostaglandin analogue (more specifically an analogue of Prostaglandin]) that works by increasing the outflow of aqueous fluid from the eyes (through the uvealsclearal tract).
It is also known by the brand name of Xalatan manufactured by Pfizer. Annual sales are approximately $1.6 billion. The patent for latanoprost expired in March 2011, and at least one generic version is now widely available in the U.S.