The S-enantiomer of Ketorolac is majorly responsible for its pharmacological activity. It inhibits the major pathways in prostaglandin synthesis. The COX-enzymes play a major role in the synthesis of prostaglandins. The COX-2 enzyme is responsible for the conversion of arachidonic acid to prostaglandins, which produces inflammation and pain. By hindering this pathway, the active constituent Ketorolac Tromethamine which is present in acular eye drops decreases pain and reduces inflammation. The effect of this medication begins within an hour and its action lasts for the duration of eight hours.