Orthostatic hypotension. Orthostatic hypotension is a sudden drop in blood pressure when a person stands up from a lying-down or seated position. This may cause dizziness, lightheadedness, and, in extreme cases, loss of balance or fainting. Studies have suggested that, in PD, this problem results from a loss of nerve endings in the sympathetic nervous system that controls heart rate, blood pressure, and other automatic functions in the body. The medications used to treat PD may also contribute to this symptom. Orthostatic hypotension may improve by increasing salt intake. Physicians treating the disorder may also reduce anti-hypertension drug dosage or by prescribing medications such as fludrocortisone.