Antibiotics in ophthalmology
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Transcript of Antibiotics in ophthalmology
Outline
• Introduction • Pathogens • Danger of overuse • Selection and administration of antibiotics• Methods of administration of antibiotics
Introduction Chemical substances produced by microorganism that has the capacity to inhibit
growth or destroy bacteria
Bactericidal Bacteriostatic
• Inhibits cell wall synthesis• Inhibits protein synthesis• Inhibits nucleic acid synthesis • Inhibits cell membrane synthesis
Bactericidal Bacteriostatic
Penicillins Chloramphenicol
Cephalosporin Erythromycin
Vancomycin Clindamycin
Gentamicin Sulfonamides
Pathogens
Gram positive and Gram negative Aerobic and anaerobic
Gram positive cocci Gram negative rodsPenicillins, cephalosporins and Vancomycin
Aminoglycosides, cephalosporins
Erythromycin, clindamycin ,chloramphenicol and tetracycline
Chloramphenicol and tetracycline
Chloramphenicol
• First line treatment of bacterial conjunctivitis(broad spectrum)
• Bacteriostatic antibiotic which inhibits protein synthesis
• Streptococci, Pneumococci and Corynebacteria
• 0.5% drops and a one percent ointment
Fluoroquinolones • Ciprofloxacin, ofloxacin(2nd generation)• Levofloxacin( 3rd generation)• Moxifloxacin, Gatifloxacin( fourth generation)• Efficacious against Gram positive and Gram
negative bacteria, particularly staphylococci• Low toxicity• Enzymic inhibition of bacterial DNA
production( DNA gyrase)• Deposit of whitish material in the base of corneal
ulcers which can make monitoring of the progress of the disease more difficult.
Penicillins
• Benzylpenicillin,Procaine penicillin, Benzathine penicillin ,Phenoxymethyl penicillin, Cloxacillin,Ampicillin/amoxicillin
• Bactericidal and inhibit cell wall synthesis• Low toxicity
Cephalosporins
• 1st generation: cefazolin, cephalexin( gram positive cocci)
• 2nd generation: cefaclor, cefuroxime sodium( gram positive and negative)
• 3rd generation: cefotaxime sodium, ceftizoxime(gram negative bacilli)
• Bactericidal and Inhibit cell wall synthesis• Allergic reaction, neutropenia and
thrombocytopenia
Aminoglycosides
• Gentamicin(0.3%), Kanamycin, Neomycin(0.3-0.5%), Streptomycin, Tobramycin(1%), amikacin
• Bactericidal and inhibit protein synthesis• Oto-toxicity and nephrotoxicity
Danger of overuse1.Hypersensitivity • Skin eruptions • Painful swollen joints, asthma and
fever• Anaphylactic shock
2. Drug toxicity• Aplastic anemia
3. Bacterial resistance 4. Alteration of normal bacterial flora
Selection and administration of antibiotics
1. Nature of the offending organism and its sensitivity to antibiotic
2. Nature of the disease, seriousness and location
3. General health, sensitivities and allergies of the patient
Methods of administration of antibiotics
• Topical • Subconjunctivally• Intracamerally• Systematically
Systematic antibiotics
• Intraocular infections• Infections of the orbit• Severe conjunctivitis• Severe corneal ulcers
Summary
• Introduction • Pathogens • Danger of overuse • Selection and administration of antibiotics• Methods of administration of antibiotics