Levofloxacin and ciprofloxacin decrease procainamide and N-acetylprocainamide renal clearances.

Ten healthy adults participated in a randomized, crossover drug interaction study testing procainamide only, procainamide plus levofloxacin, and procainamide plus ciprofloxacin. During levofloxacin therapy, most procainamide and N-acetylprocainamide (NAPA) pharmacokinetic parameters, including decreased renal clearances and renal clearance/creatinine clearance ratios, changed (P < 0.05). During ciprofloxacin treatment, only procainamide and NAPA renal clearances decreased significantly.