Infectious Diseases EFFECTS OF OFLOXACIN ADMINISTRATION ON THE RELIABILITY OF URINE GLUCOSE TESTING Tsong-Mei Tsai, Brian F Shea, Paul F Souney, Fred G Volinsky, Joseph M Scavone, and Suellen O'Neill OBJECTIVE: To study the effects of ofloxacin on the reliability of urine glucose testing. DFSIGN: Open-label, nonrandomized. SETIlNG: A university-affiliated tertiary care hospital, ambulatory clinic. PARTICIPANTS: Ten healthy volunteers (8 men and 2 women) aged 22-39 years. MAIN OUTCOME MEASURES: Phase I (in vitro) involved the addition of selected amounts of ofloxacin to a set of standard 50-mL urine samples prepared to simulate glycosuria. Phase II (in vivo) involved the oral administration of ofloxacin 400 mg to 10 subjects. Urine was collected: (I) immediately predose, (2) pooled 0-4 hours postdose, and (3) pooled 4-8 hours postdose. Known glucose concentrations were then added to these samples. Clinitest and Diastix tests were performed on all samples. The accuracy of these tests in determining glucose concentrations was compared among urine samples taken before and after ofloxacin dosing. RFSULTS: None of the ofloxacin concentrations in phase I (0, 25, 50, 100,200,400, and 800 IJg/mL) influenced these testing methods at the urine glucose concentrations of 0.0%, 0.5%, I%, and 2%. Likewise, the accuracy of these two tests was unaffected by ofloxacin administration in phase II. Tsong-Mei Tsai MS PharmD, at the time of the study, PharmD Student, Massachusetts College of Pharmacy and Allied Health Sciences. Boston, MA; now Staff Phar- macist, Cape Cod Hospital. Hyannis, MA Brian F Shea PharmD, Assistant Director for Clinical Services, Department of Phar- macy Services. Brigham and Women's Hospital, Boston, MA Paul F Souney MS, at the time of the study, Assistant Director for Clinical Services, Department of Pharmacy Services, Brigham and Women's Hospital, Boston, MA; now Medical Information Scientist, Astra Merck, Wayne, PA Fred G Volinsky MD, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital, Boston. MA Joseph M Scavone MS PharmD, at the time of the study, Professor, Clinical Phar- macy, Massachusetts College of Pharmacy and Allied Health Sciences, Boston, MA; now Professor and Head. Division of Clinical and Administrative Phar- macy, University of Iowa, Iowa City, IA Suellen O'Neill MS PharmD, Associate Professor, Clinical Pharmacy, Massachusetts College of Pharmacy and Allied Health Sciences, 179 Longwood Ave, Boston, MA 02115, FAX 617n32-2801; and Clinical Pharmacist, Brigham and Wom- en's Hospital, Boston, MA Reprints: Suellen O'Neill MS PharmD Supported by a grant from the RW Johnson Pharmaceutical Research Institute. Presented in abstract form at the American College of Clinical Pharmacy 1994 Win- ter Practice and Research Forum, February 6-9, 1994, San Diego, CA. CONCLUSIONS: In single-dose administration, ofloxacin does not interfere with Clinitest or Diastix for determining urine glucose concentrations, Ann Pharmacother 1996;30:469-72, URINE GLUCOSE TESTS are used by some patients with dia- betes to monitor their glucose control. Although blood glu- cose concentrations correlate moderately with urine glu- cose concentrations and urine glucose testing has fallen out of favor in recent years, urine glucose testing still repre- sents an inexpensive monitoring method for some patients. Patients who may choose this testing method include those who refuse to lance themselves and/or who cannot be taught the proper blood glucose monitoring technique! (e.g., elderly patients with diabetes who experience diffi- culty performing blood glucose tests or young children with diabetes who resist blood testing). Therefore, it is im- portant to identify drugs with potential to alter the accuracy of urine glucose test results. A variety of antibiotic agents, such as cephalosporins and penicillins or their metabolites, are reducing agents whose presence may render inaccurate the results of urine glucose tests.2,3 The possibility of an interaction of fluoro- quinolone antibiotics with urine glucose tests was raised by findings that some penicillins, cephalosporins, and nalidixic acid may cause false-positive reactions for glu- cose when a copper-reduction method is used.' Nalidixic acid, a naphthopyridine derivative related to the fluoro- quinolones, was found to cause false-positive urine glu- cose results when tested with Clinitest (Miles Diagnostics, Elkhart, IN).s In an in vitro study published in 1985,6the effects of several antibiotics, including ciprofloxacin, a fluoroquino- lone compound, on the accuracy of urine glucose tests were studied. Ciprofloxacin was added to the urine sam- ples of two healthy volunteers to which known quantities of dextrose also were added to simulate glycosuria. Glu- cose concentrations then were tested with several commer- cially available systems. The results suggested that cipro- The Annals of Pharmacotherapy • 1996 May, Volume 30 • 469