Urothelial mucosal concentration of levofloxacin administered before transurethral resection: Is the mucosal concentration predictable?

Background: Although it is an established surgical technique, transurethral resection (TUR) is associated with a certain incidence of postoperative ba cteriuria. Assessment was made whether the urothelial mucosal concentration of an antibiotic administered before TUR was high enough to decrease the i ncidence of urinary tract infection (UTI). Also investigated were factors p redicting the organ concentration. Methods: Forty-nine patients (45 men and four women aged 51-79 years with a median age of 70 years) who underwent TUR between August 1996 and Septembe r 1997 were enrolled in the study. Each patient received 200 mg of levoflox acin (LVFX) about two hours before surgery. Blood and bladder urine were co llected and urothelial mucosa was harvested at the time of TUR. Then the LV FX concentration in these samples was measured using high-performance liqui d chromatography. The association between drug levels, or the ratio to the serum concentration, and factors likely to affect the vascular system that delivers the drug (age, bodyweight, blood pressure, pulse rate, total chole sterol and diabetes mellitus) were investigated. Results: The mean serum drug level was 2.4 mug/mL, and it was 206.4 mug/mL in the urine and 5.7 mug/mL in the urothelial mucosa. The mean ratio of the mucosal to serum concentrations was 2.6. The urinary drug concentration sh owed no association with any of the factors assessed, while the serum conce ntration decreased with increasing bodyweight (P = 0.03). As the diastolic blood pressure increased, both the mucosal drug concentration and the mucos a/serum ratio decreased (P < 0.01). When the relationship between the serum and mucosal concentrations was investigated, no correlation was found. How ever, the mucosa/serum ratio (indicating the transfer of LVFX from the bloo d) was positively correlated with the mucosal concentration. Conclusion: Preoperative administration of LVFX was demonstrated to have po tential value for the prophylaxis of UTI after TUR. Both the mucosal concen tration and the mucosa/serum ratio were correlated with the diastolic blood pressure. As the diastolic blood pressure seems to be an indicator of the tissue concentration of LVFX, it may be possible to set the optimum dose ba sed on the diastolic pressure.