False-Positive Urine Ketone Test with Captopril

To the Editor: The oral angiotensin-converting-enzyme inhibitor captopril (3-mercapto-2-D-methylpropanoyl-L-proline or SQ-14225, Squibb) has been in use at the San Diego Veterans Administration Hospital for more than a year. I have followed nine men taking captopril, by itself or in combination with a diuretic and propranolol, for a median period of 10 months. During this time I have observed the occurrence of urine positivity for ketones by the alkaline-nitroprusside test (Keto-diastix, Ames, Elkhart, Ind., and Chemstrip 6, Bio-Dynamics, Boehringer Mannheim, Indianapolis, Ind.). In 18 urinalyses in these patients, I have been unable to obtain a negative reaction for ketones. The degree . . . No extract is available for articles shorter than 400 words.