Latanoprost is absorbed well through the cornea and completely hydrolysed to the active latanoprost acid. Highest concentrations of the acid in the aqueous humour are reached two hours after application, lowering of intraocular pressure starts after 3 to 4 hours, the highest effect is found after 8 to 12 hours, and its action lasts at least 24 hours. When latanoprost acid reaches the circulation, it is quickly metabolised in the liver by beta oxidation to 1,2-dinor- and 1,2,3,4-tetranor-latanoprost acid; blood plasma half life is only 17 minutes. The metabolites are mainly excreted via the kidney.  
Shake the drops gently to be sure the medicine is well mixed. Tilt your head back slightly and pull down on your lower eyelid. Position the dropper above your eye. Look up and away from the dropper. Squeeze out a drop and close your eye. Apply gentle pressure to the inside corner of your eye (near your nose) for about 1 minute to prevent the liquid from draining down your tear duct. If you are using more than one drop in the same eye, repeat the process with about 5 minutes between drops. If you are using drops in both eyes, repeat the process in the other eye.