Monday, October 20, 2014

Antibiotic Proliferation

There is a staggering array of antibiotics available to the modern clinician, from the old standby, penicillin, to the newest antibiotic available. “Old” antibiotics, penicillin and the sulfonamides, are effective most of the time in treating routine outpatient infections.[38] When enough infections that don’t respond to the ‘old standbys’ arise, new antibiotics soon follow.

Between 1945 and 1968, drug companies invented 13 new categories of antibiotics, but between 1968 and today, just two new categories of antibiotics have been added. According to the National Institutes of Health the lack of new antibiotics is threefold:[39]
  • There is not much money in it;
  • Inventing new antibiotics is technically challenging;
  • In light of drug safety concerns, the FDA has made it difficult for companies to get new antibiotics approved.

Antibiotics come in numerous “flavors,” there are hundreds of types and brands of antibiotics. These antibiotics each have a unique purpose in medicine and many have been developed strictly to replace an out-dated brand that no longer works.  The different categories of antibiotics in use today are:[40]
  • Penicillins
  • Cephalosporins
  • Carbapenems
  • Macrolides
  • Aminoglycosides
  • Quinolones (Fluoroquinolones)
  • Sulfonamides
  • Tetracyclines
  • Other Antibiotics

Each one of these categories has possibly dozens of different generic types and even more brand names associated with it.  For instance, penicillin, not the largest category by any means, but quite impressive:


Brand Name
Amoxil, Polymox, Trimox, Wymox
Omnipen, Polycillin, Polycillin-N, Principen, Totacillin
Geocillin, Geopen
Dynapen, Dycill, Pathocil
Flopen, Floxapen, Staphcillin
Nafcil, Nallpen, Unipen
Bactocill, Prostaphlin
Penicillin G
Bicillin L-A,
Crysticillin 300 A.S., Pentids, Permapen, Pfizerpen, Pfizerpen-AS, Wycillin
Penicillin V
Beepen-VK, Betapen-VK, Ledercillin VK, V-Cillin K



Despite all these categories and types, all antibiotics fall into one of two classifications: bactericidal and bacteriostatic.

Bactericidal antibiotics kill invading bacteria while bacteriostatic antibiotics stop new bacteria from being created. Bactericidal antibiotics include the cephalosporins and penicillins. Bacteriostatic antibiotics include tetracyclines and sulfonamides. The many variations seen and even synthetic creations are a result of the resistance that rapidly develops when a new antibiotic is unleashed on the public.

Special thanks to Dr. Grace Liu, PHARMD, from Animal Pharm for contributions to this article.

[38] Davies, J. "Antibiotic Resistance: Origins and Countermeasures ..." 2010. <>
[40] "List of Antibiotics -" 2007. 3 May. 2014 <>


  1. On an Antibiotic? You May Be Getting Only a False Sense of Security

    1. Good article! Yes, even doctors get it wrong, prescribing antibiotics for fungal or viral problems.

      I remember when our son was a baby, demanding antibiotics because we 'knew' he had an ear infection, and getting them. We'd even save unused antibiotics to give him when he seemed like he was getting an ear infection.

    2. When I worked as a cleaning lady, one of my clients went through 4 (4!) rounds of antibiotics for a sinus infection - to no avail. I pointed out to him that most sinus infections have a fungal component. He took that idea to his doctor who gave him an antifungal and the infection cleared. How sad is it when your cleaning lady knows more than your doctor?

  2. Wildcucumber,
    That reminds me of my friend who is a cleaning lady. She was fired merely because she brought up the notion of breastfeeding instead of formula to her new Mom client. The client's husband is an Obstetrician at a major hospital in Chicago. He thinks the baby is better off on formula. Regards, Regina

    1. Ouch. Regina, please tell your friend, from me, she'll have other clients who will *treasure* her for willingness to speak up like that.

  3. Here's an antibiotic issue: chronic urinary tract infections among older women. The loss of estrogen creates an environment in the urethra that is not conducive to the bacteria that fight e-coli, which is the cause of the great majority of these infections. About 30% of post-menopausal women get these infections, and a percentage of them end up with the drug resistant type.