It is determined by the condition being treated by the drug. If you are currently taking blood pressure medication, you will most likely need to continue taking it for the rest of your life. It depends on the patient condition, but even if you've quit smoking and your blood pressure has dropped, you may still require the medication because smoking is potentially harmful to your health. The average treatment course lasts six to eight weeks. Speak with your doctor if your condition has improved after six weeks of treatment.