Antibiotic (asif) nsupharmacy

AntibioticAsifur Rahman

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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