Clopidogrel works within 2 hours of taking it. Although you may not feel any difference after you start taking clopidogrel, it doesn’t mean the drug isn’t working. It is recommended to not discontinue clopidogrel without consulting with your doctor even if you feel well. You may need to continue taking it for as long as your doctor prescribed you to. Clopidogrel is generally a safe medicine for long-term consumption. Premature stopping of medication may increase risk of cardiovascular events such as heart attacks or strokes. It takes about 5 days for bleeding time to return to baseline values after treatment is discontinued.