Antibiotics Classification: comprehensive List of Common Antibiotics, Mechanism & Types

Source: https://www.scmp.com/

I. Broad Classification 

A. Chemical classification 

• B-lactam antibiotics: B-lactamase inhibitors-Clavulanic acid, Penicillins, Sulbactam, Cephalosporins, Carbapenems, Monobactams.
• Nicotinic acid derivatives: Pyrazinamide, Isoniazid, Ethionamide 
• Quinolones: Gatifloxacin Nalidixic acid, Ciprofloxacin, Norfloxacin, etc 
• Sulfonamides and related drugs: Paraaminosalicylic acid (PAS), Sulfones-Dapsone (DDS), Sulfadiazine and others. 
• Tetracyclines: Doxycycline, Oxytetracycline, etc. 
• Nitrobenzene derivative: Chloramphenicol 
• Nitroimidazoles: Metronidazole, Tinidazole, and others 
• Macrolide antibiotics: Azithromycin, Erythromycin, Clarithromycin, Roxithromycin 
• Lincosamide antibiotics: Clindamycin, Lincomycin
• Glycopeptides: Teicoplanin, Vancomycin 
• Aminoglycosides: Gentamicin, Streptomycin, Neomycin, Amikacin, etc. 
• Polypeptide antibiotics: Colistin, Polymyxin-B, Tyrothricin, Bacitracin 
• Nitrofuran derivatives:  Furazolidone, Nitrofurantoin
• Oxazolidinone: Linezolid 
• Diaminopyrimidines:  Pyrimethamine, Trimethoprim
• Others: Ethambutol, Cycloserine, Thiacetazone, Rifampin, Viomycin, Spectinomycin, Clofazimine 

B. Classification on the basis of the mechanism of action 

• Cause misreading of mRNA code and affect permeability: Streptomycin, Gentamicin, Aminoglycosides, etc 
• Inhibit DNA gyrase: Fluoroquinolones, Ciprofloxacin, etc 
• Interfere with intermediary metabolism: Trimethoprim, Sulfonamides, Ethambutol, Sulfones, PAS
• Inhibit cell wall synthesis: Bacitracin, Penicillins, Cephalosporins, Vancomycin, Cycloserine
• Cause leakage from cell membranes: Colistin, Polypeptides-Polymyxins, Bacitracin 
• Interfere with DNA function: Metronidazole, Rifampin
• Inhibit protein synthesis: Linezolid, Tetracyclines, Erythromycin, Chloramphenicol, Clindamycin 

C. Classification according to the spectrum of activity 

• Narrow spectrum: Penicillin G, Erythromycin, Streptomycin
• Intermediate spectrum: Newer macrolides, Cephalosporins (2nd/3rd Gen), Aminopenicillins, Fluoroquinolones
• Broad spectrum: Chloramphenicol, Tetracyclines

D. Classification according to the type of action 

• Primarily bacteriostatic: Linezolid, Sulfonamides, Chloramphenicol, Ethambutol, Clindamycin, Tetracyclines, Erythromycin 
• Primarily bactericidal: Aminoglycosides, Cephalosporins, Ciprofloxacin, Penicillins, Metronidazole, Rifampin, Vancomycin, Pyrazinamide, Nalidixic acid, Cotrimoxazole, Polypeptides, Isoniazid

II. Sulfonamides 

• Short-acting (4-8 hr): Sulfadiazine 
• Intermediate-acting (8-12 hr): Sulfamethoxazole 
• Long-acting (7 days): Sulfadoxine, Sulfamethopyrazine 
• Special purpose sulfonamides: Silver sulfadiazine, Mafenide, Sulfacetamide sod., Sulfasalazine, Cotrimoxazole (Trimethoprim-Sulfamethoxazole 1:5)

III. Quinolones 

• Nonfluorinated Quinolone: Nalidixic acid 
• First-generation Fluoroquinolones: Ciprofloxacin, Pefloxacin, Ofloxacin, Norfloxacin 
• Second generation Fluoroquinolones: Sparfloxacin, Moxifloxacin, Gatifloxacin, Lomefloxacin, Levofloxacin 
• Third generation Fluoroquinolones: Prulifloxacin, Gemifloxacin

IV. Beta-Lactam Antibiotics 

PENICILLINS 

A. Natural Penicillin: Benzyl Penicillin (Penicillin G) 

B. Semisynthetic Penicillins

1. Acid-resistant alternative to penicillin G: Phenoxymethylpenicillin (Penicillin V) 

2. Penicillinase resistant penicillins: Cloxacillin, Methicillin

3. Extended-spectrum penicillins 

• Aminopencillins: Bacampicillin, Amoxicillin, Ampicillin 
• Carboxypenicillins: Ticarcillin, Carbenicillin
• Ureidopenicillins: Mezlocillin, Piperacillin  

C. B-lactamase inhibitors 

Tazobactam, Sulbactam, Clavulanic acid

CEPHALOSPORINS 

First-generation 

• Parenteral: Cefazolin, Cephalothin
• Oral: Cefadroxil, Cephradine, Cephalexin 

Second generation 

• Parenteral: Cefoxitin, Cefuroxime  
• Oral: Cefprozil, Cefuroxime axetil, Cefaclor

Third generation 

• Parenteral: Cefoperazone, Ceftizoxime, Cefotaxime, Ceftazidime,  Ceftriaxone
• Oral: Ceftamet pivoxil, Cefixime, Cefdinir, Cefpodoxime proxetil, Ceftibuten

Fourth generation 

• Cefpirome, Cefepime 

V. Aminoglycoside Antibiotics 

A. Systemic aminoglycosides 

• Amikacin, Gentamicin, Netilmicin, Kanamycin, Streptomycin, Tobramycin, Sisomicin 

B. Topical aminoglycosides 

• Framycetin, Neomycin

VI. Tetracyclines 

• Demeclocycline 
• Minocycline
• Oxytetracycline 
• Doxycycline 
• Tetracycline 

VII. Chloramphenicol 

• Chloramphenicol 
• Chloramphenicol succinate
• Chloramphenicol palmitate 

VIII. Macrolide Antibiotics 

1. Erythromycin 

• Erythromycin estolate (lauryl sulfate) 
• Erythromycin ethylsuccinate 
• Erythromycin (base) 
• Erythromycin stearate 

2. Spiramycin

3. Clarithromycin 

4. Roxithromycin

5. Azithromycin

IX. Lincosamide Antibiotics 

• Clindamycin
• Lincomycin

X. Aminocyclitol Antibiotic 

• Spectinomycin

XI. Glycopeptide Antibiotics 

• Teicoplanin 
• Vancomycin

XII. Oxazolidinone 

• Linezolid 

XIII. Polypeptide Antibiotics 

• Bacitracin
• Tyrothricin
• Polymyxin B 
• Colistin sulfate 

XIV. Urinary Antiseptics 

• Nalidixic acid 
• Nitrofurantoin
• Methenamine (Hexamine) mandelate 

XV. Antitubercular Drugs 

First-line drugs 

• Ethambutol (E) 
• Isoniazid (H) 
• Pyrazinamide (Z) 
• Rifampin (R)
• Streptomycin (S)

Second-line drugs 

• Cycloserine (Cys) 
• Paraaminosalicylic (PAS) 
• Amikacin (Am) 
• Thiacetazone (Tzn) 
• Capreomycin (Cpr) 
• Ethionamide (Etm)
• Kanamycin (Kmc)

Newer Drugs 

• Clarithromycin, Rifabutin, Azithromycin, Ciprofloxacin, Ofloxacin

XVI. Antileprotic Drugs 

• Antitubercular drugs: Rifampin, Ethionamide F MF Healthcare ank 
• Sulfone: Dapsone (DDS) 
• Phenazine derivative: Clofazimine
• Other antibiotics: Ofloxacin, Minocycline, Clarithromycin