Cozaar(losartan) is an antihypertensive medication, used for treating high blood pressure. It acts by blocking the vasocontricting effects of angiotensin II protein (this keeps the blood moving along in the circulatory system with less resistance, letting the heart work (pump) with less stress. Among the side effects/adverse reactions listed, bleeding is not one of them.
Excessive bruising can be caused by many conditions or medications (blood thinners for example). You need to discuss this with your doctor, who can order the appropriate tests and treatment.
Finally, do not stop or reduce the medication you are taking for your blood pressure on your own - your doctor prescribed it and you need to take it as ordered. High blood pressure is a silent disease with few symptoms, but with huge consequences. Many people do not know they have high blood pressure until they have a heart attack or stroke.