I have found Googling about Urine antiseptic. I do not understand completely but it sounds right. It was posted by a doctor of Pharmacology of Lithuanian University of Health Sciences Kaunas, Lithuania
Many people usually get confused with the terms "antibiotic" and "synthetic antimicrobial". I suppose, instead of "synthetic antimicrobial drug" you use a term "antiseptic". Antibiotic is usually described as a substance of natural origin (plant, bacteria, fungi etc.) which was synthesized in a live organism in order to fight with infections coming from surrounding area - other live organism (thus it is called "anti-biotic"). Of course, nowadays many antibiotics are semi-synthetic or even synthetic, made purely by synthesis, as the natural antibiotics are often not very stable. Synthetic antimicrobial drugs usually are made by chemical synthesis (eg. sulfanilamides, nitrofurans, quinolones etc.). The latter group is used very often for urinary tract infections as most of fluoroquinolones are active against gram-negative bacteria causing those infections. As this group is very popular for such indication, commonly it is called "urinary antiseptics". Several aminoglycosides (antibiotics) also may be indicated for urinary tract infections, but they should be administered i.v., thus synthetic antimicrobials are more popular as they can be used orally.