Effect of ranitidine on renal clearance of lomefloxacin

Abstract

Objective: To examine the effect of ranitidine on the renal clearance of lomefloxacin.

Setting:

Department of Clinical Pharmacology, Jichi Medical School.

Methods:

Lomefloxacin 200 mg and ranitidine 300 mg or its placebo were given orally in a randomised, double-blind, crossover design. Blood and urine samples were obtained during a 24-h period after dosing.

Results:

The area under the plasma concentration-time curve and the elimination half-life of lomefloxacin were significantly increased following coadministration with ranitidine. These effects were caused by significant decreases in total (7.8%) and renal (22%) clearance of lomefloxacin. In contrast, creatinine clearance and urinary excretion of electrolytes were not influenced by ranitidine.

Conclusion:

As lomefloxacin and ranitidine are excreted in urine by renal tubular secretion, the present results suggest that the renal tubular secretion of lomefloxacin is diminished by ranitidine. As the reduction in lomefloxacin clearance is only marginal, it is probable that the drug interaction observed in this study is not of clinical significance.