To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefaclor extended-release tablets USP and other antibacterial drugs, cefaclor extended-release tablets USP should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy. The safety and effectiveness of cefaclor extended-release tablets in treating some of the indications and pathogens for which other formulations of cefaclor are approved have NOT been established. When administered at the recommended dosages and durations of therapy, cefaclor extended-release tablets are indicated for the treatment of patients with the following mild to moderate infections when caused by susceptible strains of the designated organisms. Acute bacterial exacerbations of chronic bronchitis due to Haemophilus influenzae , Moraxella catarrhalis, or Streptococcus pneumoniae. NOTE: In view of the insufficient numbers of isolates of ß-lactamase-producing isolates of Haemophilus influenzae that were obtained from clinical trials with cefaclor extended-release tablets for patients with acute bacterial exacerbations of chronic bronchitis, it was not possible to adequately evaluate the effectiveness of cefaclor extended-release tablets for bronchitis known, suspected, or considered potentially to be caused by ß-lactamase-producing H. influenzae. Pharyngitis and tonsillitis due to Streptococcus pyogenes. NOTE: Only penicillin by the intramuscular route of administration has been shown to be effective in the prophylaxis of rheumatic fever. Cefaclor extended-release tablets are generally effective in the eradication of S. pyogenes from the oropharynx; however, data establishing the efficacy of cefaclor extended-release tablets for the prophylaxis of subsequent rheumatic fever are not available. Uncomplicated skin and skin and structure infections due to Staphylococcus aureus . NOTE: In view of the insufficient numbers of isolates of Streptococcus pyogenes that were obtained from clinical trials with cefaclor extended-release tablets for patients with uncomplicated skin and skin structure infections, it was not possible to adequately evaluate the effectiveness of cefaclor extended-release tablets for skin infections known, suspected, or considered potentially to be caused by S. pyogenes.