Effect of methyldopa on urine glucose test methods
Ives, T.J.; Pevonka, M.P.; Andresen, B.D.; Yost, R.L.
American Journal of Hospital Pharmacy 37(5): 683-687
1980
ISSN/ISBN: 0002-9289 PMID: 7386480 Document Number: 158747
The effect of methyldopa on the copper sulfate reduction and glucose oxidase methods of testing for glucose in urine was studied. In an in vitro phase of the study, various concentrations of methyldopa in aqueous solution, alone and with 0.5% glucose, were tested by the reduction (Clinitest) and glucose oxidase (Tes Tape, and Clinistix), methods. Study subjects (67) were divided into 4 groups: diabetics receiving no medication for hypertension, diabetics with hypertension and receiving methyldopa, no diagnosis of diabetes mellitus or hypertension and receiving no medications, and hypertensives receiving methyldopa. Two urine samples from each subject were tested with each urine glucose test method. The glucose content of each sample was measured by o-toluidine spectrophotometry at 625 nm. No false reactions were observed in the in vitro study, except the Clinitest method gave a false-positive reaction to saturated solutions of methyldopa. The urine glucose test methods gave no false reactions in the urine of subjects receiving methyldopa. A patient in Group 2 had a glucose concentration consideraly greater than that shown by the Clinitest method. This discrepancy appears to be due to a lack of precision in the color chart at high glucose levels, not a false-positive reaction. Either testing method can be used for glucose tests in urine of diabetic patients on methyldopa regimes without concern for methyldopa-induced modification of results.