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AntibioticAsifur Rahman
Contact: 01747137920
Definitions
Antibiotics are the Substance (such as penicillin) that destroys or inhibits the growth of other pathogenic microorganisms and is used in the treatment of external or internal infections.
Originally the term antibiotic referred only to organic compounds, produced by bacteria or molds, that are toxic to other microorganisms but most are now manufactured synthetically.
Classification of Antibiotic• Mode of action
• BACTERICIDAL (kills the bug)
• BACTERIOSTATIC (stops the bug multiplying)
• Spectrum of activity
• BROAD (e.g. effective a variety of gram –ve & gram +ve bacteria)
• NARROW (e.g. effective only against gram –ve or gram +ve bacteria
• Mechanism of action / site of action;
• Inhibitors of cell wall synthesis; ( -β Lactam, Vancomycin)
• Inhibitors of cell metabolism; (Sulfonamides, Trimethoprim)
• Inhibitors of protein synthesis; (Tetracyclines, Aminoglycosides, Macrolides, Clindamycin, Chloramphenicol)
• Inhibitors of nucleic acid function or synthesis; (Floroquinolones, Rifampin)
• Inhibitors of cell membrane function; (Isoniazid, Amphotericin B)
Site of action of Antibiotics
Inhibitors of cell wall synthesis• Interfere with the synthesis of the bacterial cell wall
• Little or NO effect on bacteria that are NOT growing and dividing
Non -β lactam -β lactam group
Vancomycin Penicillins Bacitracin Cephalosporins
Polymixin B Carbapenems Telavancin Monobactams
Daptomycin -β lactam inhibitors +antibiotic combinations
Penicillin• Most widely effective and least
toxic
• Produced from fungi
• Contain β lactam ring
• Mechanism of action: Inhibit transpeptidase so cross linking between peptides not occur → Peptidoglycan of cell wall will NOT be formed.
Protein Synthesis Inhibitors
• 50S ribosome inhibitors
-Macrolides e.g. Erythromycin
-Lincosamides e.g. clindamycin, lincomyin
• 30S ribosome inhibitors
-Aminoglycosides
-Tetracyclines
Tetracycline
• Most common protein sythesis inhibitor
• Having a nucleus of four cyclic rings
• Mechanism of action :
Inhibit protein synthesis: by binding to 30s ribosomes
Prevent attachment of aminoacyl-t-RNA to the mRNA ribosome complex.
Inhibitors of nucleic acid function or synthesis
• Which interefere with the
metabolism of bacteria.
• Floroquinolone
• Rifampin
• Metronidazole
QuinolonesMechanism of action:
Inhibitors of DNA Gyrase (= Topoisomerase II) [a bacterial enzyme that winds and unwinds DNA (required for supercoiling the bacterial genome)] inhibition of DNA synthesis and transcription
Folic acid synthesis inhibitor
SulfonamidesMechanism of action:
Inhibition of folic acid synthesis
Example:
Sulfacetamide
Trimethoprim • Has similar activity to
sulphonamides
• Give synergistic effect in combination with sulphonamides
(= Cotrimoxazole)
Antibiotics side effects:The most common side effects of antibiotics :
DiarrhoeaBloating and indigestion Abdominal pain Loss of appetite Being sick Feeling sick Itchy skin rashCoughinglife-threatening allergic reaction
What Is The Rules Of Pharmacist
• The pharmacist should review the previous diseases history of the patient• Hypersensitivity reaction of Drug • Drug-drug interaction • Exact dose and frequency of the drug • When the drug should be taken before
or after meal • Suggest not to stop the antibiotics
without complete the course even feel better
Antibiotics resistance
• If the concentration of drug requires to inhibit or kill the microorganism is greater than normal use then the microorganism is considered to be resistant to the drug.
OR• The ability of a microorganism to
produce a protein that disables an antibiotic or prevents transport of the antibiotic into the cell.
Misuse of antibiotics :• Antibiotic misuse, sometimes called
antibiotic abuse or antibiotic overuse.
• The misuse or overuse of antibiotics, may produce serious effects on health.
• It is a contributing factor to the creation of multidrug-resistant bacteria, informally called "super bugs" relatively harmless bacteria can develop resistance to multiple antibiotics and cause life-threatening infections.
Inappropriate prescription • In an analysis of prescribing
practices in teaching hospitals worldwide, more than 40 % of all antimicrobials prescribed were considered inappropriate
Antibiotic resistance comes mainly because of inappropriate or improper use of antibiotics by physicians. Some 150 million prescriptions are written annually in the USA And Of those, 50 million are absolutely unnecessary or inappropriate”.
Mr: Don’t forget to take one of our antibiotics free sample before you leave the hospital
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