Severe hemorrhage, patients at risk of bleeding eg, GI ulcer, patients w/ underlying disorders of haemostasis, history of haemorrhagic CVA, undergoing major surgery including dental surgery, using anticoagulants or platelet antiaggregant drugs including low dose ASA. Renal insufficiency. Avoid abrupt discontinuation as may induce myoclonic or generalised seizures in myoclonic patients. May affect ability to drive or operate machinery. Pregnancy & lactation. Elderly.