1. Antimicrobial agents Antimicrobial agent is a chemical substance
derived from a biological source or produced
by chemical synthesis that kills or inhibits the
growth of microorganisms

2. Antibiotics Antibiotic is a chemical substance produced by
a microorganism that inhibits the growth of or
kills other microorganisms

3. Classification of AMAs
Classified in many ways;
1. Based on chemical structure
2. Mechanism of action
3.Type of organism against which primarily active
4. Spectrum of activity
5. Type of action
6. Source of origin

4. Based on chemical structure
Sulphonamides and related drugs:
Drugs are:- Sulfadiazine
Sulfones- Dapsone
Paraaminosalicylic acid(PAS)
Diaminopyrimidines:- Trimethoprim
Pyrimethamine

5. Based on chemical structure
Quiniolones:- Nalidixic acid
Norfloxacin
Ciprofloxacin
Gatifloxacin etc
Beta-lactam antibiotics:- Pencillins
Cephalosporins
Carbapenems
Monobactams

6. Based on chemical structure
Tetracyclines:- Oxyteracycline,
Doxycycline etc.
Nitrobenzene :- Chloramphenicol.
Aminoglycosides:- Streptomycin,
Gentamicin,
Amikacin,
Neomycin,
Tobramycin etc.

7. Based on chemical structure
Macrolide antibiotics:- Erythromycin, Clarithromycin,
Azithromycin,
Roxithromycin etc.
Lincosamide antibiotics:- Lincomycin,
Clindamycin etc.

8. Based on chemical structure
Glycopeptide antibiotics :- Vancomycin,
Teicoplanin.
Oxazolidinone : Linezolid
Polypeptide antibiotics :- Polymyxin-B,
Colistin,
Bacitracin,
Tyrothricin etc.

9. Based on chemical structure
Nitrofuran derivatives: Nitrofurantoin,
Furazolidone etc.
Nitroimidazole derivatives:- Metronidazole,
Tinidazole etc.
Nicotinic acid derivatives :- Isoniazid,
Pyrazinamide,
Ethionamide etc.

10. Based on chemical structure
Polyene antibiotics :- Nystatin,
Amphotericin-B,
Azole derivatives: Miconazole,
Clotrimazole,
Ketoconazole,
Fluconozole etc.

11. Based on chemical structure
Others :- Rifampicin,
Cycloserine,
Spectinomycin,
Viomycin,
Ethambutol,
Griesofulvin,
Clofazimine,
Sodium fusidate,
Thiacetazone etc.

12. Mechanism of action
Inhibit cell wall synthesis :- Pencillins,Cephalosporines, Cycloserine, Vancomycin,Bacitracin etc.
Cause leakage from cell membranes:-
Polypeptide derivatives & Polyene derivatives
Inhibit protein synthesis:-
Tetracyclines,Chloramphenicol, Macrolides,Linezolid,Clindamycin etc

13. Mechanism of action Misreading of m-RNA code and affect permeability:-
Aminoglycosides
Inhibit DNA gyrase enzyme:-
Quinolones
Interefere with DNA function :-
Rifampicin , Metronidazole etc.

14. Mechanism of action Interfere with DNA synthesis:-
Acyclovir, Zidovudine etc
Interfere with intermediary metabolism:-
Sulfonamides, Sulfones, PAS, Trimethoprim, Pyrimethamine,
Etham butol etc.

15. Type of Organisms against which will primarily active
Antibacterial:- Pencillns, Aminoglycosides,Erythromycin etc
Antifungal:- Griesofulvin, Amphotericin B, Ketoconazole, Flucanzole etc.
Antiviral:- Acyclovir,Zidovudine, Amantadine etc.
Antiprotozoal:- Chloroquine,Pyrimethamine, Metronidazole, Diloxnide etc.
Anthelmintic:- Mebendazole, Albendazole Pyrantel, Niclosamide, DEC etc.

16. Spectrum of Activity Narrow-spectrum:- PencillinG Streptomycin
Erythromycin
Broad spectrum:-
Tetracyclines
Chloramphenicol

17. Type of Action Bacteriostatic:-
Sulfonamides,Tetracyclines, Erythromycin, Chloramphenicol, Clindamycin, Linezolid etc.
Bactericidal:-
Pencillins, Cephalosporins Aminoglycosides, Polypeptides, Metronidazole, INH, Cotrimoxazole, Ciprofloxacin,Vancomycin etc.

18. Biological source of origin
Fungi :- Pencillin, Cephalosporin, Griesofulvin etc.
Bacteria:- Polymyxin B, Colistin, Bacitarcin Aztreonam, Tyrothricin etc.
Actinomycetes:- Aminoglycosides, Macrolides, Tetracyclines, Polyenes, Chloramphenicol

19. AMAs-General problems on usage
Toxicity
Hypersensitivity reactions
Drug resistance
Mutation
Superinfection
Nutritional deficiency
Masking of an infection

20. Choice of AMAs- Factors
Patient factors:- Age, Renal and hepatic function, Drug allergies, Local factors, Pregnancy, Genetic factors.
Drug factors:- Spectrum of activity, type of activity, Sensitivity of the organism, Relative toxicity, Pharmacokinetic profile, Route of administration, Evidence of clinical efficacy, and cost.
Organism- related:- On bacteriological examination

21. Thank u Philip K Mathew Clinical instructor School of Pharmacy
University of Nizwa