I have been taking lisonopril for about three months. I haven't stopped having lightheadedness since then. I would like to try a different medication, so haven't taken it for a week, but still have this dizzy sensation at different times of day, sometimes strong sometimes faint. Have I waited long enough for this medication to leave my system? Maybe I have not waited long enough for my body to adjust to the side effects? I have taken Atenolol for many years with no side effects. I am a 55 year old male. I am sedentary at work, but exercise actively after hours six days a week.