1. Classification of antibiotics.
| A. Penicillins | Penicillins consist of a thiazolidine ring connected to a B‐lactam ring to which is attached a side chain. The penicillin nucleus itself is the chief structural requirement for biological activity. Penicillins are the oldest class of antibiotics and function by inhibiting cell wall synthesis (bactericidal). A1. Natural penicillins are based on the original penicillin‐G structure. Examples include: penicillin G; procaine, penicillin V; benzathine. A2. Penicillinase‐resistant penicillins are active even in the presence of the bacterial enzyme that inactivates most natural penicillins. Examples include: cloxacillin; dicloxacillin; methicillin; nafcillin; oxacillin. A3. Extended spectrum penicillins which are effective against a wider range of bacteria. Examples include: ticarcillin; piperacillin; carbenicillin; timentin. A4. Aminopenicillins also have an extended spectrum of action compared with the natural penicillins. Examples include: ampicillin; amoxicillin. A+. Penicillin combinations. Examples include: co‐amoxyclav = 'ampicillin+ clavulanic acid' (Trade names include: Augmentin; Clavamox; Tyclav); 'ampicillin + sulbactam' (Trade names include: Ampictam; Unasyn). |
| B. Cephalosporins | Cephalosporins have a similar basic structure to penicillins but with different side chains. They function by inhibiting cell wall synthesis. B1. First generation cephalosporins; examples include: cephalothin; cefazolin; cephapirin; cephradine; cephalexin; cefadroxil. B2. Second generation cephalosporins; examples include: cefoxitin; cefaclor; cefuroxime; cefotetan; cefprozil; cefamandole, cefonicid; ceforanide, cefotiam. B3. Third generation cephalosporins, examples include: cefotaxime; ceftizoxime; ceftriaxon; cefpodoxime; cefditoren; ceftibuten; ceftazidine; cefcapene; cefdaloxime; cefetamet; cefixime; cefmenoxime; cefodizime; cefoperazone; cefpimizole. B4. Fourth generation cephalosporins, examples include: cefepime; cefpirome; cefclidine; cefluprenam; cefozopran; cefquinome. B+: Cephalosporin combinations. Examples include: 'cephradine + metronidazole'; 'ceftriaxone + metronidazole'; 'cloxacillin + gentamicin'. |
| C. Fluoroquinolones | The fluoroquinolones target the bacterial DNA gyrase and topoisomerase. They are potent bacteriocidal agents against a broad variety of micro‐organisms. Examples include: ciprofloxacin; levofloxacin; lomefloxacin; norfloxacin; sparfloxacin; clinafloxacin; gatifloxacin; ofloxacin; trovafloxacin. |
| D. Tetracyclines | Tetracyclines are bacteriostatic antibiotics active against a wide range of aerobes and anaerobic gram‐positive and gram‐negative bacteria. They inhibit bacterial protein synthesis by binding to the 30S bacterial ribosome. Examples include: tetracycline; doxycycline; minocycline. Tetracyclines should not be used with children under 8 and specifically during teeth development as they can cause a permanent brown discolouration to the teeth. This antibiotic is, therefore, unlikely to be used at caesarean section. Chloramphenicol is considered to have similar action to tetracycline. |
| E. Macrolides | Macrolide antibiotics inhibit bacterial protein synthesis. Resistance can arise. Examples include: erythromycin; clarithromycin; azithromycin. |
| F. Other beta‐lactams (carbapenems) | Carbapenems are beta‐lactams that have a broader spectrum of activity than most other beta‐lactam antibiotics. Examples include: imipenem; meropenem; ertapenem; aztreonam, mezlocillin. |
| G. Aminoglycosides | Aminoglycosides are first‐line therapy for a limited number of very specific, often historically prominent infections, such as plague, turaremia and tuberculosis. Examples include: streptomycin; gentamicin, kanamycin. |
| H. Lincosamides | Lincosamides are protein synthesis inhibitors which bind to the 50s subunit of bacterial ribosomes and inhibit early elongation of peptide chain by inhibiting transpeptidase reaction. Examples include: lincomycin; clindamycin. |
| I. Nitroimidazoles | Nitroimidazole is an imidazole derivative that contains a nitro group. It is used for the treatment of infection with anaerobic organisms. Examples include: metronidazole, tinidazol. |
| J. Others |
SeeGoodman 2008 for more detailed information about the classification and BNF 2009. Also from Wikipedia (http://www.wikipedia.org/)