Early data suggest that taking Paroxetine with Warfarin may increase your risk of bleeding. This can happen even when your blood clotting test (prothrombin time) shows no change, so a steady test result does not rule out extra bleeding.
These medicines can affect each other in a serious way. Do not start taking them together unless your doctor has said it is OK. If you already take both, do not stop either one on your own: speak to your doctor or pharmacist soon.