Flagyl or Metronidazole is the effective modern antibiotic. When administered systemically via oral tablets, Metronidazole works by inhibiting bacterial DNA synthesis hence preventing the replication of bacteria.
"An upper respiratory tract infection. Follow the procedures you are taught when you use a dose. Levofloxacin is effective against a number of gram-positive and gram-negative bacteria. Levaquin is known as the fluoroquinolone antibiotic, which is in a group of medications used generally to treat difficult infections, most commonly those that affect the urinary tract in patients."