False-Positive Hemoccult Reaction with Cimetidine

To the Editor: Because of the serious diagnostic confusion that could result if false-positive Hemoccult reactions were caused by cimetidine, I further evaluated this conclusion from the letter of Dr. Norfleet and his colleagues in the February 21 issue and must disagree with their assessment of the problem. In prospective studies of cimetidine disposition in the critically ill, we have often measured nasogastric-fluid concentrations of this compound; values have been one to five times the concomitant serum level 15 minutes after intravenous dosing and several thousand times the serum concentration 15 minutes after oral tablets. However, when these same concentrations. . . No extract is available for articles shorter than 400 words.