Antibiotics /certified fixed orthodontic courses by Indian dental academy

ANTIBIOTICS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Dr AMIT BYATNAL


CONTENTS
•Introduction
•History of Antibiotics
•Classification of antimicrobial drugs
•Problems with AMA
•Choice of AMA
•Principles of administration
•Indications for antimicrobial agents
used in dentistry

25/01/06


Beta lactam antibiotics
Quinolones
Tetracyclines
Macrolides
Nitroimidazoles
Antifungal drugs
Anti viral drugs
Maxillofacial infections
Conclusion
References

25/01/06


INTRODUCTION
 Antimicrobial

agents: Substances that will

suppress the growth/ multiplication of
bacteria and prevent their action.
 Antibiotic

agents: Chemical substances

produced by microorganisms that have the
capacity, in dilute solutions, to produce
antimicrobial action.


HISTORYOF ANTIBIOTICS
1877 Louis Pasteur Inhibition of some
microbes by others; anthrax (Bacillus
anthracis)

1908 Gelmo Synthesized sulfanilamide
(1st sulfonamide

1928 Fleming…
Penicillin notatum inhibits growth
‘PENICILLINS’

1941 Chain n Florey
Discovered properties of penicillin


1932 Domagk Prontosil
Therapeutic value sulfonamides

1943, Selman Waksman
isolated, Streptomyces griseus
…Streptomycin

Classification
A) Chemical structure

Sulfonamides and related drugs





Diaminopyrimidines





Sulfadiazine and others
Sulfones – Dapsone (DDS), Paraaminosalicylic acid (PAS).
Trimethoprim
Pyrimethamine

Quinolones




Nalidixic acid
Norfloxacin
Ciprofloxacin etc




β-lactam antibiotics







Tetracyclines





Penicillins
Cephalosporins
Monobactams
Carbapenems
Oxytetracycline
Doxycycline etc

Nitrobenzene derivative


Chloramphenicol




Aminoglycosides






Macrolide antibiotics






Streptomycin
Gentamicin
Neomycin etc
Erythromycin
Roxithromycin
Azithromycin etc

Polypeptide antibiotics





Polymyxin-B
Colistin
Bacitracin
Tyrothricin




Glycopeptides





Oxazolidinone




Linezolid

Nitrofuran derivatives





Vancomycin
Teicoplanin

Nitrofurantoin
Furazolidone

Nitroimidozoles



Metronidozole
Tinidazole




Nicotinic acid derivatives






Polyene antibiotics






Isoniazid
Pyrazinamide
Ethionamide
Nystatin
Amphotericin-B
Hamycin

Azole derivatives





Miconazole
Clotrimazole
Ketoconazole
Fluconazole




Others












Rifampin
Lincomycin
Clindamycin
Spectinomycin
Sod. fusidate
Cycloserine
Viomycin
Ethambutol
Thiacetazone
Clofazimine
Griseofulvin


B) Type of organisms against which primarily active

Antibacterial






Antifungal






Penicillins
Aminoglycosides
Erythromycin etc
Griseofulvin
Amphotericin B
Ketoconazole

Antiviral





Idoxuridine
Acyclovir
Amantadine
Zidovudine etc




Antiprotozoal







Chloroquine
Pyrimethamine
Metronidazole
Diloxanide etc

Anthelmintic





Mebendazole
Pyrantel
Niclosamide
Diethyl carbamazine etc




Bactericidal












Aminoglycosides
Bacitracin
Cephalosporins
Metronidiazole
Vancomycin
Penicillins
Ciprofloxacin
Streptomycin
Cotrimoxazole

Bacteriostatic







Chloramphenicol
Clindamycin
Erythromycin
Sulfonamides
Tetracycline
Trimethoprim


Spectrum of activity
 Narrow

spectrum
 Broad spectrum


Mechanism of action


Problems with use of AMA
Toxicity
-Local irritancy:
-Systemic toxicity:
-Therapeutic index- high, low, very low
 Hypersensitivity reactions :
 Drug resistance
- Natural- lack of metabolic process or target site
- Acquired – due to use over a period of time, mutations
or gene transfer



 Preventing

Resistance to Drugs

 Limit

the use of antimicrobial agents to the treatment
of specific pathogens sensitive to the drug being used

 Notorious-Make

sure doses are high enough, and the
duration of drug therapy long enough , combination
therapy

 Be

cautious about the indiscriminate, inadequate or
unduly prolonged use of anti-infectives


 Superinfection
 Nutritional

deficiencies
 Masking of an infection


Choice of AMA agent- patient factors
1.Age : affect kinetics of drug.




Conjugation and excretion of chloremphenicol- gray baby
syndrome
Sulfonamides displace bilirubin from PBS- kernicterus
Tetracycline accumulates in bone and teeth

2. Renal and hepatic failure: cautious use and dose
reduction
3. Local factors:
 presence of pus and secretions- AMAs, surgical
drainage reduces causative bacteria and suppresses
anaerobic bacteria
 Presence of necrotic material and infection
 Hematomas – foster growth

4.Drug allergy
5.Impaired host defense
6.Pregnancy
7.Genetic factors





Organism related considerations
Drug factors
1.
2.
3.
4.
5.
6.
7.
8.

Spectrum of activity
Type of activity
Sensitivity of the organism
Relative toxicity
Pharmacokinetic profile
Route of administation
Evidence of clinical efficacy
Cost

Microorganisms isolated from
pulpal/periapical infections
 Aerobic
 Gram

+ve cocci

Staphylococci

 Gram

+ve Baccili

Lactobaccili
Corynebacterium
Eikenella

corrodens


 Anaerobic
 Gram

+ve cocci

Peptostreptococcus

 Gram

–ve cocci

Veillonella

 Gram

+ve baccilli

Actinomyces
Eubacterium
Clostridia
Propionibacterium


 Gram

-ve baccilli

Bacteriodes
Fusobacteria
Porphyromonas
Prevotella

 Treponemas
Treponema

denticola
Treponema macrodentium
Treponema oralis
Treponema vincenti

PRINCIPLES OF ANTIBIOTIC THERAPY











PRINCIPLE 1: TO DETERMINE THE SEVERITY OF
INFECTION
PRINCIPLE 2: TO EVALUATE STATE OF PATIENT’S
HOST DEFENSE MECHANISMS
PRINCIPLE 3: TO TREAT INFECTION SURGICALLY
PRINCIPLE 4: TO SUPPORT THE PATIENT
MEDICALLY
PRINCIPLE 5: CHOOSE AND PRESCRIBE
APPROPRIATE ANTIBIOTIC
PRINCIPLE 6: PROPER ANTIBIOTIC
ADMINISTRATION

PRINCIPLES OF ANTIBIOTIC ADMINISTRATION
1.
Proper dose :
DRUG DOSAGE
‘Dose’ is the appropriate amount of a drug needed to produce a
certain degree of response in a patient.
Body size :
Individual dose = BW(kg)/70 x average adult dose


Individual dose = BSA(m2

) /1.7x average adult dose


Age :
The dose of drug for children is often calculated from the adults dose
Young’s formula
Child dose =

Age
x adult dose
Age +12

Dilling’s formula
Child dose =

Age
20 x adult dose

Clarke’s rule
Child dose =

wt in lb x adult dose
150

NEONATES AND INFANTS
 Greater

percentage of body weight
compared with body water
 Greater volume of distribution
 Increased serum half lives
 Reduced gastric emptying
 Reduced plasma protein binding
 Reduced GFR

2) Proper time interval :
3) Proper route of administration :




Parenteral administration will produce the necessary serum level
of antibiotics.
Oral route results in the most variable absorption.
For maximum absorption is taken in fasting stage.

4) Consistency in regard to route of administration :


When treating a serious, established infections, parenteral
antibiotic therapy is frequently the method of choice.




Combination antibiotic therapy :
The rationale for the use of 2 or more drugs together is to minimize
 the emergence of antibiotic resistant microorganisms
 to increase the certainty of a successful clinical outcome
 to treat mixed bacterial infections
 to prevent superinfection
 to treat severe infections of unknown etiology
 to decrease toxicity without decreasing efficacy


Examples :

Isoniazid + ethambutol + streptomycin in treatment of
tuberculosis.
Rules :

2 bactericidal drugs produce, supraadditive effects, not
antagonism. (1+1>2)

The combination of a bacteriostatic and a bactericidal
drug generally results in diminished effects. (1+1<2)

2 bacteriostatic drugs are never inhibitory. (1+1=2)



Results :
 Indifference when the effect is equal to the
single most active drug or equal to the
arithmetic sum of the two, use is not justified.
 Antagonism : when the combined drug effect is
less than the algebraic sum of the effects on
the individual drugs in the mixture.
 Synergism : ability of two antibiotics acting
together to markedly increases the rate of
bactericidal action compared to either drug
alone.


Disadvantages :











Adds nothing to therapeutic efficacy and may even reduce it
(antagonism).
Increase antibiotic toxicity and allergy.
Increase the likelihood of superinfection
Discourages specific etiologic diagnosis and promote false
security.
Encourage inadequate doses, particularly with fixed dose
combination therapy.
Increased cost
Emergence of resistant bacterial strains
Increase the environmental spread of antibiotic resistant
bacteria.


FACTORS INFLUENCING ANTIBIOTIC
THERAPY
 Minimal

Inhibitory Concentration
 Concentration-dependent Vs Timedependent antibiotics
 Post-antibiotic effects


MINIMAL INHIBITORY CONCENTRATION
 Is

the lowest antibiotic concentration that
prevents growth of microorganism after an
incubation period of 18 – 24 hours with a
standard inoculum of 104 to 105 cu/ml

 MINIMAL

BACTERICIDAL CONCENTRATION
 Is the lowest concentration of drug that causes
the complete destruction of the organisms or
permits survival of less than 0.1% of the
inoculum

RULE OF THUMB
 The

concentration of the antibiotic in the
blood should exceed the MIC by a factor
of 2-8 times to offset the tissue barriers
that restrict access to the infected site


CONCENTRATION DEPENDENT
Vs
TIME DEPENDENT ANTIBIOTICS

Aminoglycosides, metronidazole,
fluoroquinolones
Concentration dependent
Bactericidal activity depends on the
drug concentration

Beta-lactams and vancomycin
Long time of exposure of the
organisms
Better the bactericidal activity


POSTANTIBIOTIC EFFECTS
 Is

the persistent supression of microbial
growth after short time exposure to an
antimicrobial agent.

 MECHANISM

:
Is the time necessary to recover from
sublethal structural and metabolic
alterations that prevents resumption of
bacterial regrowth.

Indications for antimicrobial
agents in dentistry
Therapeutic indications
Prophylactic indications


Dental procedure for which antibiotic prophylaxis is
recommended to prevent infective endocardititis
(AHA recommendation)
 Dental extractions
 Periodontal procedures
 Replantation procedure
 Implant placement
 Initial placement of orthodontic bands
 Intra ligamentary local anesthetic injection
 Incision and drainage
Not recommended :
1.Restorative dentistry
2.LA injections
3.Intracanal endodontic treatment
4.Post-op suture removal
5.Oral radiographs

American Heart Association guidelines for antibiotic prophylaxis
Standard general
prophylaxis

Amoxicillin

Adults: 2 g
Children: 50 mg per kg
Taken orally one hour before the procedure

Patient is unable to
take oral medications

Ampicillin

Adults: 2 g
Given IM or IV within 30 minutes before the procedure

Patient is allergic to
penicillin

Clindamycin

Adults: 600 mg

or
Azithromycin
or clarithromycin

Patient is allergic to
penicillin and is
unable to take oral
medication

Clindamycin

Adults: 500 mg

Adults: 600 mg
Given IV or IM within 30 minutes before the procedure


BETA LACTAM ANTIBIOTICS
CLASSIFICATION OF PENICILLIN
I) Natural penicillins :
Penicillin G (Benzyl penicillin)
II) Acid resistant penicillins :
Phenoxymethyl penicillin (penicillin V)
III) Penicillinase – resistant penicillins :
Acid labile : Methicillin, naficillin, cloxacillin, dicloxacillin
IV) Extended spectrum penicillins :
Carboxypenicillins : Carbenicillin, ticarcillin
Aminopenicillins : Ampicillin, amoxicillin
Ureidopenicillins

 BENZYL

PENICILLIN (PENCILLIN G)
Antibacterial activity
 Inhibits

the growth of susceptible organism.
 Mainly gram +ve, gram –ve cocci and some gram +ve
bacilli with exception of enterococci.
 Cocci – Highly sensitive – Streptococci,
Pneumococci, Staph. aureus, N. gonorrhoeae, N.
meningitis
 Bacilli – B. anthracis, Corynebacterium diphtheriae,
clostridium tetany and spirochetes
 Actinomyces israelii is moderately sensitive




Preparation and dose :
 PnG inj 0.5-5 MU i.m or i.v 6-12 hours
 Procaine pencillin inj 0.5, 1 MU dry powder in vial



ADVERSE REACTIONS :
Miscellaneous reactions :
 Nausea and vomiting on oral PnG
 Sterile inflammatory reaction at the site of IM inj.
 Prolonged IV administration may cause
thrombophlebitis
 Accidental IV administration of procaine PP cause
anxiety, mental disturbances paraesthesia and
convulsions






Intolerance :




Major problem with PnG includes idiosyncratic, anaphylactic and
allergic reactions

Other allergic reactions are









Skin rashes
Serum sickness
Renal disturbance
Hemolytic disturbance
Anaphylaxis
Jarisch herxheimer reaction
Super infection
Hyperkalemia


Uses :
PnG is the drug of choice for infections











Streptococcal infections
Pneumococcal infections
Meningococcal infections
Gonorrhoea
Syphilis
Diphtheria
Tetanus and gas gangrene
Prophylactic uses




The major drawbacks of benzyl penicillin
are






Inactivation by the gastric hydrochloric acid
Short duration of action
Poor penetration into CSF
Activity mainly against gram +ve organism
Possibility of anaphylaxis


Acid resistant pencillins :
 1. Potassium phenoxymethyl penicillin (penicillin V)
Dose : infants 60 mg, children 125-250 mg given 6 hourly
CRYSTAPEN-V, KAYPEN, PENIVORAL 65, 130, 125, 250
mg tablets 125 mg/5 ml dry ser


II) Pencillinase resistant pencillins :

Methicillin






Effective in staphylococci
It is given IM or IV (slow) in the dose of 1 gm every 4-6 hours.
Haematuria, albuminuria and reversible interstitial nephritis are the
special adverse effect of methicillin.

Cloxacillin






Weaker antibacterial activity.
Distrubuted throught out the body, but highest concentration in
kidney and liver. 30% excreted in urine.
Oral dose for adults 2-4 gm divided into 4 portions children 50100mg/kg/day.
IM adults 2-12 gm/day, children 100-300 mg/kg/day every 4-6 hours.
BIOCLOX, KLOX, CLOCILIN 0.25, 0.5 gm cap, 0.5 gm/vial.





III) Extended spectrum pencillins :
Amino pencillins
Ampicillin –

Antibacterial activity is similar to that of PnG that is more
effective than PnG against a variety of gram-ve bacteria

Drug is effective against H.influenzae strep.viridans,
N.gonorrhea, Salmonella, shigellae, Klebsilla and enterococci.
Absorption, fate and excretion :

Oral absorption is incomplete but adequate

Food interferes with absorption

Partly excreted in bile and partly by kidney


Dose : 0.5-2 gm oral/IM or IV depending on severity of
infection every 6 hours
Children : 25-50 mg/kg/day
AMPILIN, ROSCILLIAN, BIOCILIN – 250, 500 mg cap 100mg/ml
ped drops, 250 mg/ml dry syr, 1 gm/vial inj.
 USES :


Urinary tract infections
 Respiratory tract infections
 Meningitis
 Gonorrhoea
 Bacillary dysentry
 Septicaemias
 SABE



 Adverse

effects :

 Diarrhoea

is frequent

 Skin

rashes is more common
 Unabsorbed drug irritates lower intestines
 Patient with history of hypersensitivity to PnG
should not be given ampicillin.


 AMOXICILLIN

:

 This

is a semisynthetic penicillin.
 (amino-p-hydroxy-benzylpenicillin)
 Antibacterial spectrum is similar to ampicillin.
 Oral absorption is better; food does not interfere;
higher and more sustained blood levels are produced.
 It is less protein bond and urinary excretion is higher
than that of ampicillin.
 Incidence of diarrhoea is less


 Dose

: 0.25-1 g TDS oral;
 AMOXYLIN, NOVAMOX, SYNAMOX, MOX,
AMOXIL 250, 500 mg cap, 125 mg/5ml dry
syr, 500 mg/vial inj.
 USES :
 Oro-dental infections
 Upper RTI
 Bronchitis
 Urinary infection
 SBE
 Gonorrhoea


BETA LACTAMASE INHIBITORS
 CLAVULANIC ACID
 Obtained from STREPTOMYCES CLAVULIGERUS
 Betalactam ring – no antibacterial activity
 Suicide inhibitor –inactivated after binding to enzyme
 Permeates the outer layers of cell wall of gram-ve bacteria
Pharmacokinetics :
Oral absorption- rapid
Bioavailability-60%
Distribution similar that of amoxicillin
Excretion-tubular secretion
Used as :
Amoxicillin+clavulanic acid (AUGMENTIN,ENHANCIN)
Ticarcillin+clavulanic acid (TIMENTIN)




Adverse effects :





Uses :







Pain-thrombophebitis
Rashes and diarrhoea
Mixed aerobic-anaerobic infections
Dental infections caused by beta lactamase producing bacteria
Gonorrhoea
Skin/soft tissue infections

SULBACTAM

CEPHALOSPORINS
Cephalosporium acremonium was the first source.
 They contain 7 amino cephalosporonic acid nucleus.
 Structurally they contain betalactam and dihydro thiazine
rings.
Mechanism of action :

Act by inhibiting bacterial cell was synthesis and are
bactericidal.



Classification
 Classified according to its antibacterial activity.
First generation cephalosporin
 Good activity against gram +ve bacteria. (except
enterococci).
 Most oral cavity anaerobes are sensitive.
Parental
Oral
CEPHALOTHIN
CEPHALEXIN
CEFAZOLIN
CEPHRADINE
CEFADROXIL


Cephalaxin and Cephadroxil :
 Useful in treating community acquired, respiratory and
urinary tract infections and in surgical prophylaxis.
 Infections of head and neck region.
 Dose: Oral 0.25 - 1g 6-8 hrly
Children : 25-100mg/kg/day
IM – 0.25g 8 hrly (mild cases) 1g 6 hrly (severe cases).
Drops – cephaxin 125mg/5ml syrup.
100mg /ml ped. drops.
SPORIDEX, CEPHAXIN, CEPHACILLIN, CEFADROX,
DROXYL


Second generation cephalosporins :
 Increased activity against gram –ve organism.
 More active against anaerobes.
Parenteral
Oral
CEFUROXIME
CEFACLOR
CEFOXITIN
CEFUROXIME AXETIL
 More active against H. influenzae, E coli.
 Dose : 250mg, 125mg, 125mg/5ml syr. and
50 mg /ml ped. drops.
KEFLOR, CEFTUM, CEFOGEN, FUROXIL.


Third Generation Cephalosporins
 High activity against gram –ve entrobacteriaceae, some
inhibit Pseudomonas as well.
 Parenteral
Oral
Cefataxime
Cefixime
Ceftizoxime
Cefpodoxime proxetil
Ceftriaxone
Cefdinir
Ceftazidime
Ceftibuten
Cefoperazone
 Dose: 250mg, 500mg, 1000mg per vial inj
 CLAFORAN, CEFIZOX,MONOCEF,CEFAZID.


Fourth Generation Cephalosporins
Similar to 3rd generation ,but is highly resistant to
betalactamases. Due to high potency and extended
spectrum, it is effective in many serious infections like
hospital acquired pneumonia, bacteremia, septicaemia.
 Parentral
Cefepime
Cefpirome
 Dose: 1-2 g i.m/i.v 12hrly
 CEFROM, CEFROTH, KEFAGE


Adverse reactions :
 Local reactions – cause pain (IM) and cause
thrombophlebitis (IV)
 Allergy – skin rashes
 Nephrotoxicity
 Bleeding disorders
 Intolerance to alcohol


Uses :
 Alternatives to penicillins.
 RTI, UTI and soft tissue infection
 Penicillinase producing staph infection.
 Septicaemias.
 Surgical prophylaxis
 Meningitis, gonorrhoea
 Typhoid
 Mixed aerobic and anaerobic infections
 Infection by odd organism or hospital infections
 Prophylactic treatment in neutropenic patients.

Dental infections
 Alternative to pencillins- hypersensitivity and resistance
 Oral – 1st and 2nd generation


Sulfonamides






Short acting(4-8hr)- Sulfadiazine
Intermediate acting (8-12hr)- Sulfamethoxazole,
Sulfamoxole
Long acting(7 days)- Sulfadoxine, Sulfamethopyrazine
Special purpose Sulfonamides – Sulfacetamide sod,
Sulfasalazine,
Mafenide,
Silver sulfadiazine


Mechanism of action
 In

bacteria, antibacterial sulfonamides act as
competitive inhibitors of the enzyme
dihydropteroate synthetase, DHPS. DHPS catalyses
the conversion of PABA (para-aminobenzoate) to
dihydropteroate, a key step in folate synthesis. Folate
is necessary for the cell to synthesize nucleic acids
(nucleic acids are essential building blocks of DNA
and RNA), and in its absence cells will be unable to
divide. Hence the sulfonamide antibacterials exhibit a
bacteriostatic rather than bactericidal effect.


 Side


effects

Sulfonamides have the potential to cause a variety of
untoward reactions, including urinary tract disorders,
haemopoietic disorders, porphyria and hypersensitivity
reactions. When used in large dose, it may develop a
strong allergic reaction. One of the most serious is
Stevens Johnson syndrome(or toxic epidermal
necrolysis).


QUINOLONES
 Entirely

synthetic antimicrobials are active
primarily against gram –ve bacteria.
 Nalidixic acid- low potency, modest blood and
tissue levels, limited spectrum, high resistance
 Fluoroquinolones – high potency, expanded
spectrum, better tissue penetrance, slow
resistance.


Mechanism
Quinolones and fluoroquinolones are bactericidal
drugs, actively killing bacteria. Quinolones inhibit
the bacterial DNA gyrase or the topoisomerase IV
enzyme, thereby inhibiting DNA replication and
transcription.


1st generation

•cinoxacin
•nalidixic acid
•oxolinic acid

Second generation
ciprofloxaci
nadifloxacin
norfloxacin
ofloxacin
rufloxacin

Third generation
gatifloxacin
levofloxacin
sparfloxacin
temafloxacin
tosufloxacin
4th generation
•clinafloxacin
•garenoxacin
•gemifloxacin
•sitafloxacin
•trovafloxacin


CIPROFLOXACIN

First generation FQ active against a broad range of bacteria
especially gram –ve aerobic bacilli.
Microbiological features :
 Rapid bactericidal activity and high potency.
 Relatively long post antibiotic effect
 Low frequency of mutational resistance.
 Protective intestinal streptococci and anaerobes are spared.
 Less active at acidic pH.


Adverse effect :
 GIT

– Nausea, vomiting, bad taste, anorexia,
diarrhoea is infrequent.
 CNS- Dizziness, headache, restlessness,
anxiety, insomnia and seizures are rare.
 Skin/hypersensitivity – rashes, pruritis, urticaria.
 Tendonitis and tendon rupture


Uses :









Broad range of infections
Minor cases, orodental -not indicated
UTI
Bacterial gastroenteritis
Prophylaxis -Typhoid
Bone, soft tissue, wound infection.
Combinations- gram –ve septicaemias
Tuberculosis

CIFRAN, CIPLOX, CIPROBID, CIPROLET
250, 500,750 mg tab, 200mg/100 ml IV infusion 3mg/ml eye drops.



 Norfloxacin

- Less potent than Ciprofloxacin.
- Used for Pseudomonas, Urinary and genital tract
infections.
NORFLOX -200,400mg
 Ofloxacin

- Activity against gram –ve bacteria
- Chlamydia and Mycoplasma
- Alternative drug for Tuberculosis
- Used mainly for Gonorrhea
ZANOCIN -200,400mg

 Levofloxacin

- Sinusitis, Pylonephritis, soft tissue infections.
LOMEF- 400mg
 Gatifloxacin

- Excellent activity against Streptococci
pneumoniae
- Indicated in community acquired pneumonia,
exacerbation of chronic bronchitis, and other respiratory
tract infections.
- Used in urinary tract infectons and gonorrhhoea.
GATIQIN – 200,400 mg tab

 Sparfloxacin

-Enhanced activity against gram –ve bacteria,
Bacteroides fragilis, anaerobes and mycobacteria.
- Indicated in Pneumonias, chronic bronchitis,
sinusitis and other ENT infections.
- Good efficacy in Mycobacterium avium infection in
AIDS patients and Leprosy.
- Higher incidence of phototoxic reactions.
SPARTA, SPARDAC -100,200 mg tab


NITROIMIDAZOLES







METRONIDAZOLE :
Introduced in 1959
Broad spectrum- e.histolytica, giardia lamblia
Anaerobic infections- chance discovery
Tinidazole, secnidazole, ornidazole, satranidazole
Cidal activity against protozoa and anaerobic bacteria
such as B fragilis, Fusobacterium, h.pyroli, spirochetes
Metronidazole is selectively toxic to anaerobic
microorganisms.


Pharmacokinetics :
 Completely absorbed from the small
intestine.
 Widely distributed in the body
 It is metabolized in liver
 Excreted in urine. 8hr


Adverse effects :






Anorexia, nausea, metallic taste and abdominal cramps
Looseness of stool is occasional,
Headache, glossitis, dryness of mouth, dizziness, rashes and transient
neutropenia.
Prolonged administration may cause peripheral neuropathy and CNS effects
Thrombophlebitis

Contraindications :
 In neurological disease, blood dyscrasias, chronic alcoholism
 First trimister of pregnancy


Ornidazole
Activity similar to Metronidazole but it is slowly
metabolised .
 Used in anaerobic infections, Amoebiasis, Giardiasis,
Trichomonasis, and bacterial vaginosis.
DAZOLIC -500mg tab, 500mg/100ml vial for i.v. infusion.



Uses- Orodental infections
 MZ

200-400mg TDS(15-30mg/kg/day) –
anaerobes not inhibited by pencillin
 ANUG- MZ+Amox - 5days
 Periodontitis, pericoronitis, acute apical
infections, endodontic infections- 5-7 days
 Aerobic and facultative bacteriaMZ+pencillin/cephalosporin/macrolides
 FLAGYL, METROGYL, METRON, ALDEZOLE
200, 400 mg tab, 200 mg/5ml susp.

TINIDAZOLE
 It is an equally efficacious congener of metronidazole
 Metabolism is slower and duration of action is longer
 Incidence of side effects is lower-Metallic taste, nausea,
rashes
 TINIBA, TRIDAZOLE, 300, 500, 1000 mg tab, 800
mg/400 ml iv
 Dental infections: 0.5g(10mg/kg) BD for 5 days
 2g orally followed 0.5g BD for 5days
 800mg iv until oral therapy


TETRACYCLINES




Napthacene derivatives made up by fusion of 4 partially
unsaturated cyclohexane radicals
Tetracyclines are bacteriostatic.
Classification
Antimicrobial activity :







Gram+ve and –ve cocci are sensitive-R
Gram+ve bacilli are inhibited
Entero bacteriaceae are highly resistant
Spirochetes are quite sensitive
All rickettsiae and chlamydiae are highly sensitive

Classification
According to source:
Naturally-occurring
Tetracycline
Chlortetracycline
Oxytetracycline
Demeclocycline
Semi-synthetic
Doxycycline
Lymecycline
Meclocycline
Methacycline
Minocycline

According to duration of
action:
Short-acting (Half-life is 6-8 hrs)
Tetracycline
Chlortetracycline
Oxytetracycline
Intermediate-acting (Half-life is ~12 hrs)
Demeclocycline
Methacycline
Long-acting (Half-life is 16 hrs or more)
Doxycycline
Minocycline
Tigecycline


 Mechanism

of action



Tetracycline antibiotics inhibit protein synthesis by
inhibiting the binding of aminoacyl-tRNA to the mRNAribosome complex. They do so mainly by binding to the
30S ribosomal subunit in the mRNA translation complex.[



Tetracyclines are widely used in treatment of
periodontal diseases.
Used in the treatment of Localised aggressive
periodontitis.




Adverse effects :








GIT-epigastric burning, nausea, vomiting, diarrhea
Liver damage
Renal failure
Phototoxicity
Effects on teeth & bones- Ca tetracycline chelate
Hypersensitivity Reactions
Superinfection; Antianabolic effect


DOSE
 Tetracycline – 1-2g per day in adults

Children over 8yrs -25 to 50mg /kg daily in 2
to4 divided dose
 TERRAMYCIN,RESTECLIN250,500mgcap,50mg/ml in10ml vial inj
 Ledermycin 150,300mg cap/tab
 DOXT, NOVADOX, TETRADOX-100mg cap.
 Cyanomycin 50,100 mg cap


Precaution :






Not to be used in pregnancy, lactation and in children
Avoided in patients on diuretics
Used cautiously in renal and hepatic insufficiency
Beyond expiry date should not be used
Do not mix injectable Tc with Pn- inactivation occurs


Local Drug Delivery Systems
One of the alternative delivery system used to control
release of drugs.

Tetracycline fibres
-An ethylene/ Vinyl acetate copolymers of fibres of 0.5mm
diameter containing Tetracycline drug. (12.7mg per 9inch)
-Packed in periodontal pocket for 10 days.
-Required to inhibit the growth of pathogens isolated from
periodontal pockets.


 Subgingival




Doxycycline

-FDA approved 10% of Doxycycline in gel system
using a syringe Atridox.
Reduction in oral microbes. No overgrowth of foreign
pathogens.

 Subgingival

Minocycline

-Sustained release form of Minocycline
microspheres(Arestin) for subgingival placement as an
adjuvant to scaling and root planing.

-2% Encapsulated into bioresorbable microspheres is
used.

ORODENTAL CONDITIONS
 Limited

use- acute dental infections
 Periodontal diseases – collagenase
 Refractory periodontal disease – 2week
tetracycline(1g/day) or doxycycline(0.10.2g/day)
 Juvenile periodontitis – 2-4 week


AMINOGLYCOSIDES
These include amikacin, arbekacin,
gentamicin, kanamycin, neomycin, netilmicin,
paromomycin, streptomycin, tobramycin, and
apramycin.

Mechanism of action
Aminoglycosides work by binding to the bacterial
30S ribosomal subunit (some work by binding to
the 50S subunit), inhibiting the translocation of
the peptidyl-tRNA from the A-site to the P-site
and also causing misreading of mRNA, leaving
the bacterium unable to synthesize proteins vital
to its growth. They kill bacteria by inhibiting
protein synthesis.

Streptomycin
Uses
•Tuberculosis in combination with other anti-TB
drugs. It is not the first line treatment.
•Plague has historically been treated with it as the
first line treatment.
•Infective endocarditis caused by enterococcus
when the organism is not sensitive to Gentamicin


MACROLIDES
Macrocyclic lactone ring with attached sugars
 ERYTHROMYCIN-Streptomyces erythreus
 Alternative to pencillin
 Water solubility is limited-stable in cold
Antibacterial activity : static- cidal
 Narrow spectrum antibiotic
 against penicillin resistant staphylococci
 Active against more gram+ve
Mechanism of action :


Dose :
 Adults

250 - 500mg 6hrly
 Children 30 – 60mg/kg/day
 Erythromycin (base) - ERYSAFE 250 mg tab
 Erythromycin stearate -ERYTHROCIN –
250,500mg tab
100mg/5ml susp;100mg/ml ped drops
 E estolate- ALTHROCIN 125mg kid tab
 E ethylsuccinate- ERYNATE


Adverse effects :
GIT – epigastric pain
 On high doses – hearing impairment
 Hypersensitivity reactions – rare
Uses :
 Substitute for penicillin, pencillin resistant infections
 Oral adm, safe and effective
 Perio/periapical/NUG/extraction
 Prophylactic use



ROXITHROMYCIN
 Semisynthetic

- long acting, stable macrolide
 Antibacterial spectrum similar to erythromycin
Dose - 150-300mg BD 30min before food
 Children - 2.5-5mg/kg BD
 ROXID, ROXIBID 150,300mg tab
 50mg kid tab,150 mg tab
Clarithromycin – CLARIMAC 250,500mg tab

CLINDAMYCIN
 It

is lincosamide antibiotic having similar action
(macrolide 50s)
 Bacteriostatic – low conc;Bacteriocidal – high
conc
 Most active against gram+ve cocci,
C.diphtheriae, Actinomyces
 Highly active against – anaerobes (B fragilis)
Pharmacokinetics :
 Oral absorption – good
 Distribution – skeletal and soft tissues
 Excreted in urine

Adverse effects :
 Rashes ,Urticaria
 Abdominal pain
 Superinfection -Enterocolitis &Diarrhoea
Uses :
 Anaerobic and mixed infections- alternative to Pn &
macro
 Abscess and bone infections-staphy and bacteroids
 Infective endocarditis
Doses : 150-300 mg QID oral ; 200-600mg I.v. 8 hourly
DALCAP, CLINCIN, DALCIN, 150, 300 mg cap,
300mg/2ml and 600 mg/4ml inj.

Anti fungal drugs


Fungus
 Composed









of a rigid cell wall made up of chitin and
various polysaccharides, and a cell membrane
containing ergosterol
 Protective layers of the fungal cell make the organism
resistant to antibiotics
 Related groups of anti fungal agents
1.Antibiotics
 A. Polyenes
 B. Heterocyclic benzofuram
2.Antimetabolites
3. Azoles
 A.Imidazoles
 B.Triazoles
4.Allylamine
5.Topical agents

Nystatin







A polyene derived from Streptomyces noursei
Binds to sterols of fungal cell membrane
Topical antifungal agent- fungicidal
2nd choice to clotrimazole
1 lac units-4 times a day, 10-14 days
Suspended with glycerine


CLOTRIMAZOLE
 Effective

in the topical treatment. Esp, athletes
foot, otomycosis and oral, cutaneous
candidiasis.
 10mg -3-4times a day. Gel or lotion-denture
stomatitis
 Angular chelitis
 well tolerated although Local irritation and
burning
 No systemic toxicity is seen after topical use.
 SURFAZ, CLOTRIN, CLODERM, 1% lotion,
cream, powder 100mg tab.

ANTIVIRAL DRUGS


Anti-herpes virus




Idoxuridine,acylovir,famiclovir

Anti-retrovirus


NRTI





NNRTI






Ritonavir
Indinavir

Antiinnfluenza virus




nevirapine

PI




Zidovudine
Lamivudine

Amantadine

Nonselective antiviral drugs-ribavirin

Acyclovir
 Indications:

Herpes simplex virus (HSV) 1
and 2 infections; HSV encephalitis; shingles
and chickenpox; ointment for herpes
infections; cream for cold sores
 Actions: Inhibits viral DNA replication


Symptoms
 Rapid

progressing- facial cellulitis-HI/SP
 Chronic/ slowly progressing-odontogenicstaphylococcal/mixed
 >101 F –nonodontogenic- hospitalization
 Colour:red/ violecious
 Swelling: indurated, non fluctuant or
erythematous – cellulitis
 Pointed, fluctuant or productive- abscess

Management
Upper face
 Outpatient: amoxicillin clavulanate or cefaclor orally
 Ceftriaxone- 1 day iv
 Inpatient : cefuroxime/ ampicillin+ sulbactam 7-10 days
 Odontogenic –pencillin/ clindamycin, surgical
intervention
Lower face
 Outpatient: cephalexin, amoxicillin clavuanate,
erythromycin
 Inpatient : iv cefazolin, clindamycin


Some of the commonly used drugs
 Amox-250,500mg-tid
 250mg-Rs

67.50
 500mg-Rs120.80
Children20-40mg/kg body weight-tid
-125,250mg




Cephalexin(sporidex)
 250,500mg
 250mg-10tab-Rs66.50
 500mg-10tab-Rs120.50
 125mg,250mg/5ml
 125mg;30ml-Rs34.50
 250mg;30ml-Rs52.60

 Sporidex dispersible

tabs

 125mg-10tabs-Rs32.25
 250mg-10tabs-Rs69.95

 Paed

drops-100mg/ml

 10ml-Rs33

 Metrogyl
 200mg;tab

10-Rs3.64
 400mg;tab 10-6.31- given tid for 5-10 days
 Suspension; 200mg /5ml-30ml-Rs8.09
60ml-Rs-12.27


KNOW THE BUGS, KNOW THE DRUGS


List of references
Essentials of medical pharmacology :
KD TRIPATHI; 5th edi.
 Clinical pharmacology – Bennet & Brown 9th ed
 Oral & maxillofacial infections – Topazian 4th ed
.Text book of pediatric dentistry – Damle 3rd ed
 Caranza Text book of periodontology 10th



Questions to ask
before starting antibiotics
•Does this patient actually need
antibiotics?
•What is best treatment?
•What are the likely organisms?
•Where is the infection?
•How much, how often, what
route, for how long?
•How much does it cost?
•Are there any problems in
using antibiotics in this
patient?

Thank you
For more details please visit


Antibiotics /certified fixed orthodontic courses by Indian dental academy

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