Acute orthostatic hypotension when starting dopamine agonists in Parkinson's disease

Objective: To study the frequency and severity of acute orthostatic hypotension (OH) in patients with Parkinson's disease who are starting dopamine agonist therapy. Patients and Methods: In the context of an outpatient clinical practice, 29 consecutive patients with Parkinson's disease who were starting dopamine agonist therapy were brought into the clinic for their first dose of agonist. After a baseline supine and standing blood pressure assessment, patients were given a test dose of either pergolide mesylate (0.025, 0.05, 0.125, or 0.25 mg), pramipexole dihydrochloride (0.125 mg), or ropinirole hydrochloride (0.125 or 0.25 mg). At 3 selected times, blood pressure readings were repeated in the supine and standing positions. Main Outcome Measure: Orthostatic hypotension was defined as a drop in either systolic blood pressure of more than 25 mm Hg or diastolic pressure of more than 10 mm Hg. Patients with OH before the administration of the dopamine agonist were excluded. Results: Ten subjects (34%) met the criteria for acute OH. There was no evidence that OH was related to the use of a specific dopamine agonist or the concurrent use of levodopa. Of the patients who met the criteria for OH, only 3 (30%) had symptoms of OH, such as lightheadedness or general malaise. Conclusions: Acute OH occurs frequently when starting dopamine agonist therapy in Parkinson's disease, but is frequently not appreciated by patients. Knowledge of acute blood pressure responses may be useful when making decisions regarding agonist titration schedules in clinical practice.