Fig. 1: Common Antibacterial Antibiotics


Selected antibiotics and their modes of action.
(U.S. Brand names are in parentheses; ®.)

1. Inhibit synthesis of peptidoglycan causing osmotic lysis.

a. Penicillins: penicillin G (Pfizerpen; Bicillin; Wycillin), penicillin V (Betapen; Pen-Vee K), methicillin (Staphcillin), ampicillin (Omnipen; Polycillin), oxacillin (Bactocill ), amoxicillin (Amoxil; Biomox; Polymox), ticarcillin (Ticar), carbenicillin (Geocillin), piperacillin (Pipracil), mezlocillin (Mezlin), bacampicillin (Spectrobid), dicloxacillin (Dynapen), nafcillin (Nallpen; Unipen).

b. Penicillins plus beta lactamase inhibitors or compounds preventing antibiotic degradation on the kidneys: amoxicillin + clavulanate (Augmentin), ticarcillin + clavulanate (Timentin), ampicillin + sulbactam (Unasyn), piperacillin + tazobactam (Zosyn), imipenem + cilastatin (Primaxin) .

c. Cephalosporins: cefaclor (Ceclor), cefadroxil (Duricef), cefazolin (Ancef; Kefzol), cefixime (Sulprax), cefepime (Maxipime), ceftibuten (Cedax), cefprozil (Cefzil), cefpodoxime (Vantin), cefotaxime (Claforan), cefotetan (Cefotan), cefoxitin (Cefoxitin; Mefoxin), ceftazidime (Ceptaz; Fortaz; Tazicef; Tazidime), ceftizoxime (Cefizox), ceftriaxone (Rocephin), cefuroxime (Ceftin; Kefurox; Zinacef), cephalexin (Biocef; Keflex; Keftab), cephradine (Velosef), cefdinir (Omnicef), cefditoren pivoxil (Spectracef), loracarbef (Lorabid), cefpirome (Cefrom), cefoperazone (Cefobid), cefepime (Maxipime).

d. Carbapenems: imipenem (Primaxin), meropenem (Merrem), ertapenem (Invanz), doripenem (Doribax). .

e. Monobactems: aztreonam (Azactam).

f. Glycopeptides: vancomycin (Lyphocin; Vancocin).

g. Bacitracin (AK-Tracin; Baci-IM; Baci-Rx; Ocu-Tracin; Ziba-Rx)

h. Fosfomycin (Monurol )

2. Alter cytoplasmic membrane causing cellular leakage

a. Polymyxins: colistimethate(Coly Mycin M), polymyxin B (Aerosporin; also mixed with other antibiotics in ointments such as Cortisporin, Neosporin, and LazerSporin).

b. daptomycin (Cubicin)  Daptomycin disrupts the bacterial cytoplasmic membrane function by apparently binding to the membrane and causing rapid depolarization. This results on  a loss of membrane potential and leads  to inhibition of protein, DNA and RNA synthesis, resulting in bacterial cell death.

3. Alter bacterial ribosomes, blocking translation and causing faulty protein synthesis

a. Causing faulty protein synthesis by binding to the 30S ribosomal subunit

1. Aminoglycosides: amikacin (Amikin), tobramycin (Nebcin), gentamicin (Garamycin; Genoptic; Gentacidin; Gentak; Gentasol; Ocu-Mycin), kanamycin (Kantrex), neomycin (mixed with other antibiotics in antibiotic ointments such as Neosporin, Cortisporin, and LazerSporin), paromomycin (Humatin), tobramycin (AK-Tob; Tobrasol; Tobrex; Nebcin; Tobi).

2. Tetracyclines: tetracycline (Ala-Tet; Brodspec; Panmycin; Sumycin; Tetracon), minocycline (Arestin; Dynacin; Minocin; Vectrin), doxycycline (Adoxa; Atridox; Doryx; Monodox; Vibramycin), demeclocycline (Declomycin), tigecycline (Tygacil).

3. Spectinomycin (Trobicin)

b. Causing faulty protein synthesis by binding to the 50S ribosomal subunit

1. Macrolides: erythromycin (A/T/S; Akne-Mycin; E.E.S.; Emgel; E-Mycin; Eryc; Erycette; Erygel; Erymax; EryPed; Ery-Tab; Erythra-Derm; Erythrocin; Erythrocot; PCE; Romycin; Roymicin; Staticin; Theramycin; T-Stat), azithromycin (Zithromax), clarithromycin (Biaxin), dirithromycin ( Dynabac), roxithromycin (Roxl-150, Roxo, Surlid, Rulide, Biaxsig, Roxar, Roximycin, Roxomycin, Tirabicin and Coroxin).

2. Lincosamides: lincomycin (Bactramycin; Lincocin; Lincomycin), clindamycin (Cleocin; Clinda-Derm; Clindagel; Clindamax ).

3. Chloramphenicol: (AK-Chlor; Chloromycetin; Chloroptic; Ocu-Chlor)

4. Oxazolidinones: linezolid (Zyvox), sivextro

5. Streptogramins: a combination of quinupristin and dalfopristin (Synercid)

6. Telithromycin (Ketek)

4. Inhibiting bacterial nucleic acid synthesis

a. Inhibit DNA replication by inhibiting one or more of a group of enzymes called topoisomerases that are essiential for bacterial DNA replication and transcription

Quinolones: norfloxacin (Noroxin, Chibroxin), ciprofloxacin (Cipro; Ciloxan; Ciprodex), ofloxacin (Floxin; Ocuflox), enoxacin (Penetrex), lomefloxacin (Maxaquin), levofloxacin (Levaquin; Quixin), gatifloxacin (Tequin), moxifloxacin (Avelox), nalidixic acid (NegGram), gemifloxacin (Factive).

b. Inhibit bacterial DNA synthesis by blocking synthesis of tetrahydrafolate, a cofactor needed to make nucleotide bases

1. Sulfonamides: sulfanilamide (AVC), sulfisoxazole (Gantrisin; Truxazole), sulfacetamide (AK-Sulf; Bleph-10; Isopto Cetamide; Klaron; Ocu-Sul; Ocusulf; Ovace; S.O.S.S.; Sebizon; Sodium Sulamyd; Sulf-10; Sulfac 10%; Sulfacet; Avar; Clenia; Nicosyn; Novacet; Plexion ; Prascion Rosac; Rosanil; Rosula; Sulfacet-R; Zetacet), Sulfadiazine (Sulfadiazine), sulfabenzamide + sulfacetamide + sulfathiazole (Gyne Sulf; Triple Sulfa), sulfisoxazole + erythromycin (Pediazole; Eryzole).

2. Trimethoprim (Primsol; Proloprim; Trimpex), trimethoprim + polymyxin B (Polytrim; Proloprim; Trimpex)

3. Trimethoprim + sulfamethoxazole ( Bactrim; Bethaprim; Septra; SMX-TMP Plain; Sulfatrim; Uroplus).

4. Trimetrexate (NeuTrexin)

c. Drugs that are activated by the microbial proteins flavodoxin and feredoxin found in microaerophilc and anaerobic bacteria and certain protozoans. Once activated, the drug puts nicks in the microbial DNA strands.

Metronidazole (Flagyl; RTU; MetroCream; Metro; Metronidazole; Noritate; Protostat; Rozex)

d. Drugs that inhibit bacterial RNA synthesis by binding to RNA polymerase.

Rifampin or Rifampicin:  rifadin, rifater combined with isoniazid and pyrazinamide , rimactane.

5. Multiple Action: blocks aerobic energy production and synthesis of proteins, DNA, RNA, and cell walls

a. Nitrofurantoin (Furadantin; Macrobid; Macrodantin; Nitro Macro)

b. Nitrofurazone (Furacin)

c. Furazolidone (Furoxone)

6. Antituberculosis drugs

Rifampin (Rimactane, Rifadin), rifapentine (Priftin), isoniazid (Nydrazid), ethambutol (Myambutol), capreomycin (Capastat), cycloserine (Seromycin), ethionamide (Trecator), rifabutin (Mycobutin), aminosalicylic acid (Paser D/R), clofazimine (Lamprene), rifampin + isoniazid (Rifamate), rifampin + isoniazid + pyrazinamide (Rifater).

For a more detailed description of any specific antimicrobial agent, see the website of RxList - The Internet Drug Index.

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Updated: August 157, 2005
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