Clinical laboratory abnormalities

Data on repeated laboratory findings in 974 patients from 25 collaborative centers conducting studies on levodopa in parkinsonism have been analyzed in an attempt to evaluate the significance of laboratory abnormalities. The hematologic tests included hemoglobin, hematocrit determinations, white cell count, and Coombs test; the blood chemistry tests consisted of blood urea nitrogen, serum glutamic oxalacetic transaminase and other standard liver function tests, fasting blood sugar, uric acid, and protein‐bound iodine. The data show that, to date, there has been no significant interference with the hematologic system, renal function, liver function, or endocrine function. Occasional abnormalities in blood urea nitrogen, the serum glutamic oxalacetic transaminase test for liver function, fasting blood sugar, and protein‐bound iodine were found. The percentages of abnormalities for each of the tests are tabulated. Also studied were electrocardiogram, repeated 1,209 times and found abnormal in 28 per cent, and the electroencephalogram 334 times, found abnormal in 150. In general, few, if any, abnormalities could be clearly related to the ingestion of levodopa. Minor elevations in liver function test values returned to normal spontaneously within a month or two without discontinuation of levodopa. Continued careful monitoring by laboratory tests is nonetheless urged, because patients with Parkinson's disease tend to develop other illnesses.