Antibiotics in
Dentistry
Dr Mohammed Malik Afroz
Format
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Introduction
History
Definition
Classifications
Antibiotics
Problems that arise with use of antibiotics
Principles of antibiotic selection
Combinations of antibiotics
Antibiotic prophylaxis
Conclusion
Introduction
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Host , Environment & Organisms
Normal oral flora- 300 types of bacteria
Microorganisms breach the host defense
‘Antibiotics’ Mean – Kill or prevent
Antibiotics are substances produced by various
species of microorganisms (bacteria,fungi,
actinomycetes) that supresses growth of other
microorganisms and eventually may destroy them
--Goodman & Gilman’s IXth edition
Classifications
Chemical structure:
1. Sulfonamides & related
Sulfadizine, Sulfones,
Paraaminosalicylic acid
2. Diaminopyrimidines:
Trimethoprim ,
Pyrimethamine
3. Quinolones:
Norfloxacin , Ciprofloxacin
4. β-lactum antibiotics:
Penicillins, Cephalosporins
5. Tetracyclines:
Doxycycline , Minocycline
6. Nitrobenzene derivatives
Chloramphenicol
7. Aminoglycosides:
Streptomycin , Gentamicin
8. Macrolide antibiotics:
Erythromycin ,
Roxithromycin
9. Polypeptide antibiotics:
Polymyxin-B , Bacitracin
10. Glycopeptides:
Vancomycin
11. Oxazolidinone: Linezoid
Classifications
Chemical structure:
12. Nitrofuran derivatives:
Nitrofurantoin
13. Nitroimidazoles:
Metronidazole , Tinidazole
14. Nicotinic acid derivatives:
Isoniazide , Pyrazinamide
15. Polyene antibiotics:
Nystatin , Amphotericin-B
16. Azole derivatives:
Miconazole , Clotrimazole
17. Others:
Rifampin , Clindamycin ,
Lincomycin , Ethambutol ,
Griseofulvin
Classification
• Mechanism of action:
Bacteria responsible for infections
AEROBIC BACTERIA
ANAEROBIC BACTERIA
 Gram-positive cocci
• Streptococcus Viridans
• hemolytic
• Staphylococcus
 Gram-negative bacilli
• Haemophilus influenza
• Eischeria coli
• Klebsiella
• Eikenella corrodens
 Gram-positive cocci
• Streptococcus
• Peptostreptococcus
 Gram-negative bacilli
• Porphyromonas
• Prevotella
• Fusobacterium
• Bacteroids fragilis
Beta – Lactum Antibiotics
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Most commonly used in dentistry
Antibiotic in the group are:
Penicillins
Cephalosporins
Monobactum
Carbapenems
Penicillins
• Present source – Penicillium chrysogenum
• Mechanism of action: inhibits synthesis of peptidoglycans –
formation of cell wall deficient bacteria – lysis
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Spectrum of activity: Bactericidal
Classification:
Naturally occuring penicillins: Penicillin G , Penicillin V
Semisynthetic penicillins:
Short acting: Ampicillin,Amoxycillin,Amoxycillin with
Clavulanic acid
Long acting: Procaine penicillin
Ampicillin
• Semisynthetic aminopenicillin
• Extended/broad spectrum
• Spectrum of activity: Bactericidal
• gram+ve cocci , bacilli , gram-ve bacilli
• Many have developed resistance
• Pharmacokinetics:
• Absorption: well absorbed orally, causes Diarrhoea
• Excretion : primary – kidneys
enterohepatic circulation – bile & reabsorbed
Ampicillin
• Uses :
• Dental infections – gram+ve , gram-ve & anaerobic bacteria
• Medical: UTI, respiratory tract infections , bacillary dysentary ,
typhoid fever , cholysistitis
 Meningitis
 Gonorrhoea
 Subacute bacterial endocarditis
• Dose: 0.5-2g oral/im/iv every 6 hours
Children: 25 – 50 mg/kg/day
AMPILIN, ROSCILLIN, BIOCILIN – 250,500 mg cap ; 125,250 mg/5ml dry syr ;
100 mg/ml pediatric drops ; 250,500mg & 1 g/vial inj
Amoxicillin
Similar to Ampicillin , except :
• Good oral absorption – food does not interfere – higher &
more sustained blood levels
• Diarrhoea incidence is less
• Most frequently used in dental infections
Dose :250-500mg TDS for 5 days
• 1st choice of drug for prophylaxis following dental surgery
• Preferred for typhoid , bronchitis , UTI , SABE , gonorrhoea
• Dose: 0.25 – 1g TDS oral/im
AMOXYLIN , NOVAMOX: 250mg,500mg cap ; 125mg/5ml dry syr
AMOXIL , MOX: 250mg,500mg cap ; 125mg/5ml dry syr ;
250mg, 500mg/vial inj
Beta-Lactamase Inhibitor
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Beta-Lactamase : family of enzymes
produced by many gram+ve & gram-ve
bacteria that inactivate beta-lactam
antibiotics by opening the beta-lactum ring
• Inhibitor of beta-lactamase enzyme are:
1. Clavulanic acid
2. Sulbactum
Clavulanic acid
• Mechanism of action: ‘Progressive’ inhibitor- binds
with B-lactamase – inhibition increases with time.
 Pharmacokinetics:
• Rapid oral absorption
• Plasma t1/2 – 1hr & tissue distribution = amoxicillin
• Coamoxiclav- combination of amoxicillin & clavulanic
acid
• Excreted by glomerular filteration
 Adverse effects: GI tolerance is poor in children
Candida stomatitis/vaginitis ; rashes
Clavulanic acid
• Uses:
• Coamoxiclav is indicated for:
Dental infections by B-lactamase producing bacteria
Skin , soft tissue infections, intra-abdominal & gynaecological
sepsis , urinary , biliary & respiratory infections
Gonorrhoea
AUGMENTIN , ENHANCIN , AMONATE: Amoxicillin250mg+ clavulanic acid
125mg tab ;1-2 tab TDS
AUGMENTIN: Amoxicillin1g + clavulanic acid 0.2g vial ; inject 1 vial deep im
or iv 6-8 hourly – severe infections
Cephalosporins
• Semisynthetic B-Lactum antibiotic derived from
‘Cephalosporin-C’.
Parenteral
• First generation
• Second generation
• Third generation
• Fourth generation
Oral
• Cephalothin
• Cefazolin
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• Cefamandole
• Cefuroxime
• Cephalexin
• Cefadroxil
• Cefotaxime
• Ceftrioxone
• Cefoperazone
• Cefixime
• Cefepime
• Cefachlor
• Cefuroxime axetil
Cephalosporins
• Mechanism of action: inhibition of bacterial cell wall
synthesis but bind to different protein than penicillin
• Spectrum of activity: Bactericidal
Broad spectrum agents – therapuetically & prophylactically
used in place of penicillin & erythromycin
• Excreted rapidly by kidneys
First generation Cephalosporins
• Cephalothin – resistant to penicillinase –
staphylococcal infections
• Cefazolin – good tissue permeability – surgical
prophylaxis
• Cephalexin - most common alt – amoxicillin;
minor oral infections – abscess / cellulitis;
Pre , intra & post-operative – surgical procedure
Not effective – anaerobic gram-ve organisms
• Cefadroxil - good tissue permeability – alveolar
bone. Sustained action
• Cefazolin : Dose : 0.25g 8 hourly (mild)
1g 6 hourly i.m./i.v. (severe)
• ALCIZON , ORIZOLIN 0.25 , 0.5 , 1g vial inj
• Cephalexin :0.25-1g 6-8 hourly
(25 -100mg/kg/day)
• CEPHACILLIN – 250, 500mg cap
• SPORIDEX , ALCEPHIN , CEPHAXIN – 250, 500mg cap
125mg/5ml dry syrup, 100mg/ml paediatric syrup
• Cefadroxil: Dose: 0.5-1g BD
• DROXYL 0.5-1g tab , 250mg/5ml syr
• CEFADROX 0.5g cap , 125mg/5ml syr , 250mg kid tab
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Cephalosporins
• Uses:
• Dental infections:
• Alternative to penicillin
1st gen – cephalexin ,
cephadroxil gram+ve
aerobic bacteria
2nd gen – cefaclor ,
cefuroxime axetil- oral
anaerobes
Cephalexin , cephadroxil – alt
to amoxicillin for
prophylaxis
• Medical uses:
• Respiratory , urinary , soft
tissue infections – gram-ve
organisms
• Cefazolin-surgical prophylaxis
• Gonorrhoea :ceftriaxone
• Meningitis : 3rd gen
• Typhoid ; alternate to
ciprofloxacin
• Nosocomial infections:3rd
• Mixed aerobic-anaerobic inf
in cancer pts …:3rd gen
Cephalosporins
• Adverse effects:
• Hypersensitivity reactions
• Nephrotoxicity : combination with other nephrotoxic drugs –
avoided
• Diarrhoea
• Low WBC count
• Causes Pain – site of injection
• Causes Bleeding – in patients with hypo – prothrombinaemia
– malnourished pts
Thank You