The effectiveness of midodrine administration for the treatment of dizziness in patients with orthostatic dysregulation (OD) was investigated. Midodrine (4mg/day) was administered for 8 weeks to 42 patients with dizziness who were confirmed to have orthostatic dysregulation based on a questionnaire. The patients were subdivided into 3 groups on the basis of blood pressure and Schellong test results. Twenty patients had low systolic pressure, less than 100mmHg at rest in the supine position, twelve patients had orthostatic hypotension, and the other ten patients were diagnosed to have orthostatic dysregulation without low systolic pressure or orthostatic hypotension.
The effects of the drug were evaluated objectively on the basis of improvement in the Schellong test results, and subjectively on the basis of the patient's perception of symptoms as described in the OD questionnaire results at 4 and 8 weeks after midodrine administration. In general, the symptoms tended to decrease after treatment in most of the patients. In patients with hypotension or orthostatic hypotension, in particular, excellent improvement was achieved. Improvement occurred not only in the patients symptoms, but also in low blood pressure at bed rest and Schellong test results. These observations suggest that administration of midodrine was efficacious in the treatment of dizziness in patients with orthostatic dysregulation as a probable consequence of poor cir culatory function due to autonomic imbalance.
