Simvastatin is for cholesterol, it's controlling the levels of "bad" cholesterol in your blood. Your levels may go up if you stop taking them altogether. 40mg is a standard dose of this particular brand, it's what I was on.
Why are you asking, thebarron? Sounds like you have a selection of drugs for hihg blood pressure and related vascular problems, why would you stop taking 'em?
You could if you were a woman.......but it would not be advisable as all 3 drugs are secreted in the mother;s milk and would adversely affect the baby.