Antibiotics in Dentistry
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Transcript of Antibiotics in Dentistry
KMCT DENTAL COLLEGEManassery, Mukkam
ANTIBIOTICS
IN
DENTISTRY
Presented By:
Niyas Ummer1st Year PG
Department of Oral Medicine and Radiology
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Overview
Introduction Terminology History Classification General Considerations
o Routes of administrationo Choice of agento Combined useo Problems with useo Prophylactic useo Failure
Commonly used antibiotics in dentistryo Mechanism of actiono Useso Adverse Effectso Interactionso Contra-indicationso Dosage and availability
Recent Advances Misuse Conclusion References
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Introduction to Antibiotics
The magic word ‘Antibiotic’ inevitably springs to mind whenever an infection has to be dealt with. Antimicrobial drugs are the greatest contribution to 20th century of therapeutics - ‘Antibiotic era’. Their advent changed the outlook of the physician about the power drugs can have on diseases.
Antibiotics are essential weapon against infection; hence wise use of antibiotics requires the clinician to take the stance that positive indication must be present before antibiotic drugs are prescribed. As a class, antibiotics are one of the most frequently used as well as misused drugs.
Terminologies Used
Antibiotics: Substances produced by microorganisms, which selectively suppress the growth of or kill other microorganisms at very low concentrations. The term "antibacterial" is derived from Greek anti - "against” and baktēria, "staff, cane". The term "antibiotic" derived from anti and bios, "life".
Chemotherapy: Treatment of systemic infections with specific drugs that selectively suppress the infecting microorganism without significantly affecting the host
Antimicrobial Agent: Synthetic as well as naturally obtained drugs that attenuate microorganisms
History of Antibiotics
Milestones in History
Louis Pasteur observed, "if we could intervene in the antagonism observed between some bacteria, it would offer perhaps the greatest hopes for therapeutics“
Term 'antibiosis‘ coined by the French bacteriologist Jean Paul Vuillemin Antibiosis first described in 1877 in bacteria when Louis Pasteur and Robert
Koch observed that an airborne bacillus could inhibit the growth of Bacillus anthracis
Renamed ‘antibiotics’ by Selman Waksman, an American microbiologist, in 1942
Synthetic antibiotic chemotherapy began in Germany with Paul Ehrlich in the late 1880s
In 1928, Alexander Fleming observed antibiosis against bacteria by a fungus of the genus Penicillium. He postulated the effect was mediated by an antibacterial compound named penicillin, and that its antibacterial properties could be exploited. He attempted to use a crude preparation to treat some infections, but unable to pursue its further development.
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Period of Empirical Use (16th - 17th Century)
Mouldy curd by Chinese on boils Chaulmoogra oil by Hindus in leprosy Chenopodium by Aztecs for intestinal worms Mercury by Paracelsus for syphilis Cinchona bark for fevers
Phase of Dyes and Organometallic Compounds
Paul Ehrlich (1890-1935) coined the term ‘chemotherapy’. He developed two antibiotics, atoxyl for sleeping sickness and arsphenamine for syphilis.
Modern Era of Antibiotics
Domagk (1935) developed Prontosil for use in pyogenic infections. It came to be known as the first commercially available antibiotic.
Paul Ehrlich
DomagkProntosil
ChenopodiumChaulmoogra
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Classification of Antibiotics
Based on Chemical Structure:
Sulfonamides Sulfadiazine, Sulfones (Dapsone)
Diaminopyridines Trimethoprim, Pyrimethamine
Quinolones Nalidixic Acid, Norfloxacin, Ciprofloxacin
β-lactam Penicillins, Cephalosporins, Monobactams, Carbapenems
Tetracyclines Oxytetracycline, Doxycycline
Nitrobenzene derivative Chloramphenicol
Aminoglycosides Streptomycin, Gentamycin, Amikacin, Neomycin
Macrolide Erythromycin, Clanthromycin, Azithromycin
Lincosamide Lincomycin, Clindamycin
Glycopeptide Vancomycin, Teicoplanin
Oxazolidinone Linezolid
Polypeptide Polymyxin-B, Colistin, Bacitracin, Tyrothricin
Nitrofuran derivatives Nitrofurantoin, Furazolidone
Nitroimidazoles Metronidazole, Tinidazole
Nicotinic acid derivatives Isoniazid, Pyrazinamide, Ethionamide
Polyene Nystatin, Amphotericin-B, Hamycin
Azote derivatives Miconazole, Clotrimazole, Ketoconazole, Fluconazole
Others Rifampin, Spectinomycin, Sodium fusidate, Cycloserine, Viomycin, Ethambutol, Thiacetazone, Clofazimine, Griseofulvin
Based on type of organisms against which primarily active:
Antibacterial Penicillins, Aminoglycosides, Erythromycin, etc.
Antifungal Griseofulvin, Amphotericin B, Ketoconazole, etc.
Antiviral Acyclovir, Amantadine, Zidovudine, etc.
Antiprotozoal
Chloroquine, Pyrimethamine, Metronidazole, Diloxanide, etc.
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Anthelmintic Mebendazole, Pyrantel, Niclosamide, Diethyl carbamazine, etc.
Based on spectrum of activity:
Narrow-spectrum
Penicillin G, Streptomycin, Erythromycin
Broad-spectrum Tetracyclines, Chloramphenicol
Based on type of action:
Primarily bacteriostatic
Sulfonamides, Erythromycin, Tetracyclines, Ethambutol, Chloramphenicol, Clindamycin, Linezolid
Primarily bactericidal
Penicillins, Cephalosporins, Aminoglycosides, Vancomycin, Polypeptides, Nalidixic acid, Rifampin, Ciprofloxacin, Isoniazid, Metronidazole, Pyrazinamide, Cotrimoxazole
Based on source obtained from:
Fungi Penicillin, Cephalosporin, Griseofulvin
Bacteria Polymyxin B, Colistin, Bacitracin, Tyrothricin, Aztreonam
Actinomycetes
Aminoglycosides, Tetracyclines, Chloramphenicol, Macrolides, Polyenes
Choice of an Antibiotic Agent
Choosing the right antibiotic depends on qualities of patient, the infecting organism and the drug, as given below.
Patient Factors
a) Age:
o The age of the patient affects kinetics of drugs, including its absorption, metabolism and excretion.
b) Genetic Factors:
o Primaquine, nitrofurantoin, sulfonamides, chloramphenicol and fluoroquinolones produce haemolysis in Glucose-6-Phosphate Dehydrogenase deficient patient
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
c) Renal and Hepatic Function:
o Cautious use and dose modification advised when the organ for disposal of the drug is defective/diseased
Renal Failure
Dose reduction in mild failure
Aminoglycosides, Amphotericin B, Cephalosporins, Ethambutol, Vancomycin, Flucytosine
Dose reduction in moderate-severe failure
Metronidazole, Carbenicillin, Cotrimoxazole, Aztreonam, Meropenem, Fluoroquinolones, Clarithromycin, Imipenem
Drugs to be avoidedCephalothin, Talampicillin,Nalidixic acid, Tetracyclines, Nitrofurantoin (except doxycycline)
Liver Disease
Dose reductionChloramphenicol, Isoniazid, Metronidazole, Rifampin, Clindamycin
Drugs to be avoided
Erythromycin estolate, Tetracyclines, Pyrazinamide, Nalidixic acid, Talampicillin, Pefloxacin
d) Local Factors:
o Pus and secretions decrease the efficacy of sulfonamides and aminoglycosides
o Necrotic material or foreign body makes eradication impossibleo Haematomas foster bacterial growtho Lowering of pH at the site of infection reduces activity of macrolides
and aminoglycosideso Anaerobic environment in the centre of an abscess impairs bacterial
transport processes which concentrate aminoglycosides in the cello Penetration barriers hamper the access to the site of infectiono Some drugs like trimethoprim and fluoroquinolones attain high
concentration due to ion trapping
e) Drug Allergy:
o If a drug has caused allergic reaction, it has to be avoided in that patient.
o β-lactams, sulfonamides, fluoroquinolones, nitrofurantoin frequently cause allergy.
f) Impaired Host Defense:
o Pyogenic infections are common in neutropenic patients.
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
o Infections by low grade pathogens and intracellular organisms occur if cell-mediated immunity is impaired.
o In a patient with normal host defense, a bacteriostatic AMA may achieve cure.
o But in an impaired host defense, intensive therapy with cidal drugs is recommended.
g) Pregnancy:
a. All AMAs should be avoided in the pregnant because of risk to the foetus
b. Penicillins, many cephalosporins and erythromycin - safec. Tetracyclines - acute yellow atrophy of liver, pancreatitis and kidney
damage in the mother - teeth and bone deformities in the offspringd. Aminoglycosides - foetal ear damage
Risk Category of Drugs in Pregnancy
Category
Description
AAdequate studies in pregnant women have failed to demonstrate a risk to the foetus
B
Adequate human studies are lacking, but animal studies have failed to demonstrate a risk to the foetus amoxicillinor,Adequate studies in pregnant women have failed to demonstrate a risk to the foetus, but animal studies have shown an adverse effect on the foetus
C
No adequate studies in pregnant women and animal studies are lacking or have shown an adverse effect on foetus, but potential benefit may warrant use of the drug in pregnant women despite potential risk
DThere is evidence of human foetal risk, but the potential benefits from use of the drug may be acceptable despite the potential risk
XStudies in animals or humans have demonstrated foetal abnormalities, and potential risk clearly outweighs possible benefit
Organism-related Factors
a) Initial Empirical Therapy:
Identification of the microorganism and antimicrobial sensitivity testing are time consuming, expensive & impractical. Sometimes, it is not possible to obtain appropriate samples of infected material. Furthermore, well defined site and features of the infection enable organisms causing such infections to be reliably deduced. SO empirical therapy is usually carried out. In addition, most dental infections are acute in nature, hence treatment cannot be delayed.
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
b) Identification of Causative Organism:
Type of bacteria (aerobic/anaerobic) and their specific identification is necessary for proper management of the condition. Most odontogenic infections (70%) are caused by a mixture of aerobic and anaerobic bacteria. Well-circumscribed chronic non-advancing abscesses contain mostly anaerobic bacteria. Cellulitis type of lesions show exclusively aerobic bacteria. When the infection is contained longer & controlled, only anaerobic flora is evident. Abscesses may contain anaerobic bacteria.
c) Antibiotic Sensitivity for Causative Organism:
Antibiotic therapy is initial / empirical or definitive, depending on whether the organism is identified precisely.
Drug Factors
a) Spectrum of Activity:
For definitive therapy, a narrow-spectrum drug which selectively affects the concerned organism is preferred. For empirical therapy, often a broad-spectrum drug has to be used to cover all likely pathogens.
b) Type of Activity:
Acute infections resolve faster with a cidal drug and reduces the number of bacteria at the site of infection. For patients with impaired host defence, life-threatening infections, infections at less accessible sites (SABE) or when carrier state is possible (typhoid), a bactericidal drug is preferred.
c) Sensitivity of the Organism:
On the basis of MIC values (if available) and consideration of postantibiotic effect
d) Relative Toxicity:
Less toxic antibiotic is preferred
e) Pharmacokinetic Profile:
Antibiotic has to be present at the site of infection in sufficient concentration for an adequate length of time. Aminoglycosides and fluoroquinolones produce ‘concentration-dependent inhibition’, where the inhibitory effect depends on the ratio of peak concentration to the MIC. β-lactams, glycopeptides and macrolides produce ‘time-dependent inhibition’ where the antimicrobial action depends on the length of time the concentration remains above MIC. Drug which penetrates better and attains higher concentration at the site of infection is more effective.
f) Route of Administration:
Less severe infections warrant the use of oral antibiotic. Serious infections require parenteral antibiotics.
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
g) Evidence of Clinical Efficacy:
Relative value of different AMAs in treating an infection is decided on the basis of comparative clinical trials. Optimum dosage regimens and duration of treatment are also determined on the basis of such trials. Reliable clinical trial data, if available, is the final guide for choice of the antibiotic.
h) Cost:
Less expensive drugs are to be preferred
Principles of Antibiotic Dosing for Orofacial Infections
Employ high doses for a short duration Achieve blood levels of antibiotic at 2-8 times the MIC Use frequent dosing intervals Determine the duration of therapy by remission of disease Proper time intervals (four times the T½) Proper route of administration Penetration of drug
Routes of Administration
Antibiotic Combinations
More than one AMAs are frequently used concurrently to treat infections.
Objectives:
i. To achieve synergism and enhance antimicrobial actionii. To reduce severity or incidence of adverse effects
iii. To prevent emergence of resistanceiv. To broaden the spectrum of antimicrobial action for polymicrobial infectionsv. For empirical therapy of an infection in which the cause is unknown
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Prophylactic Use
Antibiotic prophylaxis with dental procedures is reasonable only for patients with cardiac conditions associated with the highest risk of adverse outcomes from endocarditis.High Risk Patients:
Prosthetic cardiac valve or prosthetic material used in valve repair Previous endocarditis Congenital heart disease only in the following categories: Unrepaired cyanotic congenital heart disease, including those with palliative
shunts and conduits Completely repaired congenital heart disease with prosthetic material or
device, whether placed by surgery or catheter intervention, during the first six months after the procedure
Repaired congenital heart disease with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device
Cardiac transplantation recipients with cardiac valvular disease
Dental procedures for which prophylaxis is reasonable:
All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth, or perforation of the oral mucosa.
Antibiotic prophylaxis is NOT recommended for:
Routine anesthetic injections through noninfected tissue Taking dental radiographs Placement of removable prosthodontic or orthodontic appliances Adjustment of orthodontic appliances Placement of orthodontic brackets Shedding of deciduous teeth Bleeding from trauma to the lips or oral mucosa
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Problems associated with Antibiotic use
1. Toxicity
a) Local Irritancy:
Toxicity that is exerted at the site of administration. Gastric irritation, pain and abscess formation are evident. Complication of IV administration that commonly arises is thrombophlebitis of the injected vein. E.g. erythromycin, tetracycline, chloramphenicol
b) Systemic Toxicity:
Dose related and predictable organ toxicities can also occur.
High Therapeutic Index Penicillins, some Cephalosporins, Erythromycin
Low Therapeutic Index Aminoglycosides, Tetracyclines, Chloramphenicol
Very Low Therapeutic Index
Polymyxin B, Vancomycin, Amphotericin B
2. Hypersensitivity
Reactions that range from rashes to anaphylactic shock, that are unpredictable and unrelated to dose. Practically all AMAs are capable of causing hypersensitivity. More common culprits include penicillins, cephalosporins, sulfonamides, fluoroquinolones.
3. Drug Resistance
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
It is the unresponsiveness of a microorganism to an AMA. It can be of the following types:
Natural Resistance:Microorganisms inherently lack the metabolic process or the target site which
is affected by the particular drug. It is generally a group or species characteristic.
Acquired Resistance:Development of resistance by an organism (which was sensitive before) due
to the use of an AMA over a period of time. It occurs by mutation or gene transfer.
Cross Resistance:Acquisition of resistance to one AMA conferring resistance to another AMA,
to which the organism has not been exposed. It may be complete, or partial; two-way, or one-way.
Prevention:
No indiscriminate and inadequate or unduly prolonged use – prefer symptom determined shorter courses
Prefer rapidly acting and selective (narrow spectrum) AMAs Broad-spectrum drugs - only when a specific one cannot be determined or is
not suitable Use combination of AMAs for prolonged therapy Infection by organisms notorious for developing resistance treated intensively
4. Superinfection
Appearance of a new infection as a result of antimicrobial therapy. It is commonly associated with the use of broad/extended-spectrum antibiotics. It is more common when the host defense is compromised. Sites involved are those that normally harbor commensals. They are generally more difficult to treat.
To minimize superinfections:
Use specific (narrow-spectrum) AMA Do not use antimicrobials to treat trivial, selflimiting or untreatable (viral)
infections Do not unnecessarily prolong antimicrobial therapy
5. Nutritional Deficiencies
Some of the B complex group of vitamins and Vitamin K are synthesized by the intestinal flora. Prolonged use of antimicrobials which alter this flora result in vitamin deficiencies.
6. Masking of an infection
Short course of an AMA may be sufficient to treat one infection but only briefly suppress another one contacted concurrently. Other infection will be masked initially, but will manifest later in a severe form.
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Failure of Antibiotic Therapy
Success of therapy measured either clinically in terms of improvement in symptoms/signs or microbiologically as eradication of the infecting organism. Antimicrobials may fail to cure an infection/fever, or there may be relapses. When a real or apparent failure of the antimicrobial regimen occurs, the diagnosis and therapy should be reviewed.
Causes of failure:i. Improper selection of drug, dose, route or duration
ii. Treatment begun too lateiii. Failure to take necessary adjuvant measuresiv. Poor host defensev. Infecting organism present behind barriers
vi. Trying to treat untreatable infections or other causes of fevervii. Presence of dormant or altered organisms which later give rise to a relapse
Common Antibiotics in Dentistry
1. PENICILLINS
Classification:
Natural penicillin Penicillin G
Acid resistant penicillin Penicillin V
Penicillinase resistant penicillin Methicillin
β lactamase inhibitors Clavulanic acid
Penicillin active against pseudomonas
Carboxy and ureidopenicillins
Extended spectrum penicillinsAminopenicillins: AmpicillinCarboxypenicillin: CarbenicillinUreidopenicillin: Piperacillin
a) Penicillin G
Antibacterial Spectrum: Streptococci, pneumococci, N. gonorrhoea, clostridia, M. TB, spirochaetes, actinomyces israeli, B. anthracis
Mechanism of Action:Interfere with the synthesis of bacterial cell wall
Adverse Effects:
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Local irritancy and direct toxicity Hypersensitivity reactions Super infections Jarisch-Herxhemier reactions
Uses:i. Dental infections: periodontal abscess, periapical abscess, pulpitis
ii. Medicinal uses: Gonorrhoea, syphilis, tetanus
Preparations and Dose:Sodium penicillin G inj.: Benzyl pen 0.5,1 MU inj.Procaine penicillin G inj.: 0.5,1 MU dry powders in vialFortified procaine penicillin G inj.: 3+1 lac U vialBenzathine penicillin G: Penidure LA 0.6, 1.2, 2.4 MU as dry
powder in vial
Contraindications: Allergies Poor renal function
Drug Interactions:Oral contraceptives
Pregnancy category: B
Trade Names: PENCIP, PENTIDS, SODICILLIN
b) Ampicillin
Antibacterial Spectrum: E. coli, proteus, salmonella, shigella and many Gram positive organisms like cocci, bacilli etc.
Mechanism of Action:Interfere with the synthesis of bacterial cell wall
Adverse Effects: Diarrhoea Rashes
Drug Interactions:Oral contraceptives
Uses:i. Urinary tract infection
ii. Respiratory tract infectioniii. Meningitis, gonorrhoeaiv. SABE, typhoid fever
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
v. Bacillary dysentery, septicemias
Contraindications: Allergies Poor renal function
Dosage:0.5-2g oral/I.M/I.V every 6 hrs for adults25-50 mg/kg/day for children
Trade Names: AMPISYN, AMPILIN, AMPI-500, ALFACILLIN, AMPICILLIN
c) Amoxicillin
Similar to ampicillin in all aspects except: Oral absorption is better Incidence of diarrhea It is less active against Shigella and H. influenzae
Dosage:250-500mg TDS given for 5 daysUses:Choice of drug for prophylaxis of local wound infection as well as distant infection following dental surgery
Trade Names: MOX, AMOX, AMOXIL, AMOXIPEN, AUGMENTIN (Amoxicillin and clavulanic acid)
d) Methicillin
MRSA (methicillin resistant staph. aureus) are organisms resistant to methicillin.
Drug of choice: vancomycin/linezolid. Ciprofloxacin can also be used
2. CEPHALOSPORINS
Mechanism of Action:Interfere with the synthesis of bacterial cell wall
Classification:
a) First Generation:
Effective against gram positive cocci, including penicillinase producing staph, most anaerobes and community acquired infections caused by E.coli, Proteus and klebsiella
Examples are: Cefalexin, Cefadroxil
b) Second Generation:
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Show increased antibacterial activity Cefmandole has markedly increased activity. But it has less activity
against strep. Cefactor, increased activity against H.influenzae
c) Third Generation:
Ceftriaxone shows high efficacy in bacterial meningitis, multi resistant typhoid fever, complicated urinary tract infections, abdominal sepsis and septicemias
Examples are: Cefpodoxime proxetil, cefoperazone
d) Fourth Generation:
Examples are: Cefepime, cefpirome
Dosage: 250-1000 mg q 6 h x 7-10 days
Uses:i. Dental infections
ii. General medical uses like meningitis, typhoid etc
Adverse Effects: Pain after I.M injection Diarrhoea Hypersensitivity reactions Nephrotoxicity Bleeding Neutropenia and thrombocytopenia
Contraindications: Allergies Poor renal function
Drug Interactions: Probenecid
Pregnancy Category: B
3. TETRACYCLINES
Antibacterial Spectrum: Cocci: N. gonorrhoea and N. menigitidisBacilli: Clostridia and anaerobic bacilli, H. ducreyiSome spirochetes, mycoplasma, actinomyces
Mechanism of Action:Inhibit protein synthesis by binding to 30S ribosomes - prevent aminoacyl transfer RNA from entering the acceptor sites on the ribosome
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Uses:
i. Orodental infectionsii. Gingivitis
iii. Periodontal ligament related diseases
Adverse Effects:
Irritative effects Liver damage Kidney damage Phototoxicity Teeth and bones: Enamel hyperplasty, inhibition of fibula growth, dental
caries, brown discolouration, formation of calcium tetracycline crystals Antianaboilic effects Increased intracranial pressure Diabetes insipidus Vestibular toxicity Hypersensitivity Superinfection
Dosage: 100 mg qd-bid x 7-14 days
Contraindications:
Food Pregnancy
Drug Interactions:Anti-epileptics
Pregnancy category: D
4. CHLORAMPHENICOL
Antibacterial Spectrum: H. influenzae, salmonella, klebsiella along with those sensitive to tetracycline
Mechanism of Action:Inhibit protein synthesis binding to 50S subunit
Uses:
i. Enteric feverii. H. influenzae meningitis
iii. Anaerobic reactions iv. Intraocular infections
Adverse Effects:
Bone marrow depression Hypersensitivity reactions Irritative effects
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Superinfections Gray baby syndrome
Dosage: Daily dose not to exceed 2–3 g; duration of therapy to be < 2 weeks, total dose in a course < 28 g
Contraindications:Pregnancy
Drug Interactions:
Inhibits metabolism of tolbutamide, chlorpropamide, warfarin, cyclophosphamide and phenytoin
Phenobarbitone, phenytoin, rifampin enhance metabolism Antagonize the cidal action of β-lactams/aminoglycosides on certain bacteria
Pregnancy category: D
5. AMINOGLYCOSIDES
Antibacterial Spectrum: Gram negative bacilli, H.ducreyi, yersinia pestis, gram positive cocci, enterococci
Mechanism of Action:Inhibit protein synthesis
Uses:
i. Tuberculosisii. Plaque
iii. Tularemiaiv. Brucellosisv. Enterococcal infections
vi. Subacute bacterial infections
Adverse Effects:
Ototoxicity Nephrotoxicity Neuromuscular blockade Allergy Superinfection
Dosage: 0.5-1 gm by I.M injection
Contraindications:
Pregnancy (risk of foetal ototoxicity)
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Concurrent use of other ototoxic drugs, e.g. high ceiling diuretics, minocycline.
Concurrent use of other nephrotoxic drugs, e.g. amphotericin B, vancomycin
Precautions:
Patients past middle age Kidney damage
Drug Interactions:Cautious use of muscle relaxants
Trade Names: GENTACIL, GENTYCIN, GENTAMICIN
6. MACROLIDES
Antibacterial Spectrum: Streptococcus, staphylococcus, gonorrhea, clostridia
Mechanism of Action:Act by inhibiting protein synthesis by binding to the bind to the 23S rRNA of 50S ribosomal subunits
Uses:
i. Dental infections: Periodontal, periapical abscess, necrotizing ulcerative gingivitis, gingival cellulites
ii. General medical uses: Pharyngitis, tonsillitis, rheumatic fever
Adverse Effects:
Gastrointestinal problems Hypersensitivity Reversible hearing impairment
Dosage:Erythromycin: 250-500 mg 6 hourly (max.4g/day), children 30-60-mg/kg/dayAzithromycin: 500 mg once daily 1hr before or 2hrs after food for 3 days
Precautions:Poor hepatic function
Drug Interactions:Cytochrome P-450
Pregnancy category: B
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
7. METRONIDAZOLE
Antibacterial Spectrum: Entamoeba histolytica, giardia lamblia, anaerobic bacteria, like clostridium, spirochetes, peptococcus
Mechanism of Action:Reduced intermediate interacts and breaks the bacterial or parasitic DNA
Adverse Effects:
Anorexia, nausea, metallic taste, abdominal cramps Headache, dryness of mouth, rashes, and Glossitis (rare) Thrombophlebitis of the injected vein
Uses:
i. Orodental infectionsii. Drug of choice in acute necrotizing ulcerative gingivitis
iii. Periodontitis, pericoronitis, acute apical infections, brain abscessiv. Drug of choice for all forms of anaerobic infections, acute dysentery, liver
abscessv. Drug of choice for intestinal giardiasis and trichomonas vaginitis
Dosage: 200-400 mg TDS (15-30mg/kg/day)
Trade Names: METROGYL, FLAGYL
Contraindications:
Pregnancy Chronic alcoholism
Precautions:Poor hepatic function
Drug Interactions:
EtOH Warfarin Li+
Pregnancy category: D
8. FLUOROQUINOLONES
Antibacterial Spectrum: All organisms are susceptible except some strep, anaerobic cocci, mycobacterium
Mechanism of Action:Bind to A subunit of DNA gyrase with high affinity and interfere with strand cutting and resealing functions
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Adverse Effects:
GIT: Nausea, vomiting, bad taste, anorexia CNS: Dizziness, headache, restlessness, anxiety Skin/hypersensitivity
Uses:
i. Urinary tract infectionsii. Gonorrhea
iii. Soft tissue, bone and joint infections especially gram negative organismsiv. Community acquired pneumonia
Dosage: Ciprofloxacin 250-500 mg QD x 7-10 days
Trade Names: BIOCIP, CIP, CIPLOX, CIPLO
Contraindications:
Children (damage of the cartilage in weight bearing joints) Pregnancy
Drug Interactions:
Probenacid Warfarin
Pregnancy category: C
9. CLOTRIMOXAZOLE
Combination of trimethoprim and sulfamethoxazole (1:20)
Antibacterial Spectrum: Same as sulfonamide but include salmonella typhi, klebsiella, enterobacter
Mechanism of Action:Inhibit bacterial dihydrofolate reductase
Uses:
i. Pneumocystis carnii pneumonia in AIDS patientsii. Tonsillitis, Pharyngitis, sinusitis
iii. Urinary tract infections, orodental infections
Adverse Effects:
Methamoglobinemia Blood dyscarasis Nausea, vomiting, stomatitis, headache and rashes Neonatal hemolysis
Contraindications:Pregnancy
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Newer Antibiotics
i. Ceftolozane/tazobactam: Antipseudomonal cephalosporin/β-lactamase inhibitor combination (cell wall synthesis inhibitor)
ii. Ceftazidime/avibactam: Antipseudomonal cephalosporin/β-lactamase inhibitor combination (cell wall synthesis inhibitor)
iii. Ceftaroline/avibactam: Anti-MRSA cephalosporin/ β-lactamase inhibitor combination (cell wall synthesis inhibitor)
iv. Plazomicin: Aminoglycoside (protein synthesis inhibitor)v. Eravacycline: A synthetic tetracycline derivative / protein synthesis inhibitor
targeting the ribosomevi. Brilacidin: Peptide defense protein mimetic (cell membrane disruption)
Misuse in Dentistry
Treatment of Nonresponsive Infections:
Diseases caused by viruses are self-limited
Therapy of Fever of Unknown Origin:
Fever persisting for 2 or more weeks – only 1/4th are due to infections Require treatment with agents that are not used commonly for bacterial
infections, surgical drainage or prolonged courses of pathogen-specific therapy
May mask an underlying infection, delay the diagnosis, and prevent identification of the infectious pathogen
Noninfectious causes
KMCT DENTAL COLLEGE ORAL MEDICINE AND RADIOLOGY
Inappropriate Reliance on Chemotherapy Alone:
Drainage, debridement, and removal of foreign body Misuse in Dentistry Improper Dosage: Dosing errors (wrong frequency of administration or use of either an
excessive or a subtherapeutic dose) Excessive amounts can result in significant toxicities Too low a dose may result in treatment failure or resistance
Lack of Adequate Bacteriological Information:
Bacterial cultures and Gram stains of infected material Frequent use of drug combinations or drugs with the broadest spectra Agents are selected more likely by habit than for specific indications Dosages employed are routine rather than individualized
Conclusion
Antibiotic therapy is an art and a science. There are so many confounding variables (such as suspected pathogen, ability to establish drainage, pharmacokinetic properties of the drug, mechanism of action of the antibiotic, virulence of the infection, the current health status of the host, and host defense mechanisms), that it is not possible to make antibiotic therapy into a mechanistic technologic science.
The most important decision for the dental practitioner to make is not only which antibiotic to use but whether to use one at all.
References
i. Essentials of Medical Pharmacology, 6th Edition – K. D. Tripathiii. Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 11th
Editioniii. Pharmacology and Pharmacotherapeutics - R. S. Satoskariv. Manoj Kumar Jain, Sheetal Oswal K. Antibiotics in Dentistry – An Art and
Science. Annals of Dental Specialty 2013; 1(1):20-25.v. Prevention of Infective Endocarditis: Guidelines From the American Heart
Association, by the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease. Circulation, 2007; 116: 1736-1754.
Online sources:http://www.medclik.comhttp://en.wikipedia.org/wiki/Antibacterial