The systolic and diastolic blood pressure (BP), with the patient in the standing, sitting and recumbent positions, and the pulse rate were determined at various time intervals in 51 parkinsonian patients during prolonged levodopa therapy. Hypotension was observed in 10 patients (19.6 per cent). In 5 of these cases it was clinically significant and associated with syncope, so the drug had to be discontinued after two to sixteen weeks of therapy. In the other 5 cases the hypotension was transitory and not clinically significant, so the drug did not have to be discontinued. These 5 cases were included with the 46 cases subjected to statistical analysis. In the 46 cases, both the analysis of variance and the correlation coefficients showed that the dosages of levodopa had no significant effect either on the BP or the pulse. In attempting to produce a clinically significant therapeutic effect with a minimum of toxic effects it was found that a statistically significant lower dosage of levodopa was necessary for the “older” subjects (those over age 70) as compared to the “younger” subjects (those aged 70 or younger). Furthermore, such dosage differences appeared to be more marked in women than in men. In both the normotensive and the hypotensive responses to levodopa, no orthostatic effect was observed nor was there a dose‐related response of the BP within the dosage range used in this study (a maximal level between 2.0 and 4.0 gm daily).
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