Of those cured by surgery, some will later develop the disease in the other adrenal gland, and will require medical therapy. Short answer - no. Balanced against this are the demands of the work-up, both in terms of the blood tests and the inpatient stays. A fludrocortisone suppression test involves a 5 day inpatient stay with up to 4 blood tests daily. The adrenal venous sampling involves a 2 day hospital stay with an invasive procedure in the X-Ray department.
Medical therapy is usually effective in reducing blood pressure and is usually well tolerated.
However, it does not reduce aldosterone levels. There is evidence to suggest that elevated aldosterone levels may contribute to thickening of the heart and blood vessels even if blood pressure has been returned to normal by medications. Spironolactone, which blocks the aldosterone receptor, is the better agent from this point of view. There are several options. Which is chosen depends on the availability of tests in your area, the advice of your doctor, and your informed choice.