This document discusses various types of antibiotics, including their classification, uses, side effects and dosages. It covers penicillin, amoxicillin, cephalosporins, erythromycin, metronidazole, combination therapies, and factors involved in antibiotic treatment and selection. Guidelines for dosing antibiotics in children and pregnant women are also presented.

1. Dr. Firas Kassab

2. • Substances derived from microorganisms
• Suppress the growth of or kill the other microorganisms
• Bacteriostatic v/s Bactericidal
Dr.Firas Kassab

3. A. BASED ON CHEMICAL STRUCTURE
• B-lactam antibiotics - Penicillins, cephalosporins
• Tetracyclines - Doxycycline
• Aminoglycosides –streptomycin, gentamicin
• Sulphonamides – Sulfamethoxazole
• Macrolide -Erthyromycin
• Quinolones - Ciprofloxacin
Dr.Firas Kassab

4. Dr.Firas Kassab

5. • Narrow spectrum
Penicillin G, streptomycin and erythromycin.
• Broad spectrum
Tetracyclines, chloramphenicol.
• Extended spectrum
Ampicillin, amoxycillin
Dr.Firas Kassab

6. • Discovered in 1929, it was first antibiotic drug to be used.
• The drug of choice for the initial empirical management of
odontogenic infections.
• Bactericidal
• Narrow but appropriate spectrum [gram positive cocci (except
staphylococci) and oral anaerobes]
• Little or no toxicity ( 3 % of population)
Dr.Firas Kassab

7. CLASSIFICATION OF PENICILLIN
I) Natural penicillins :
Penicillin G (Benzyl penicillin) - parenteral administration
II) Acid resistant penicillins :
Phenoxymethyl penicillin(penicillin V)- taken orally
III) Penicillinase – resistant penicillins : used for penicillinase producing
staphylococci
Methicillin, naficillin, cloxacillin, dicloxacillin
IV) Extended spectrum penicillins :
Carboxypenicillins : Carbenicillin, ticarcillin
Aminopenicillins : Ampicillin, amoxycillin
Ureidopenicillins
Dr.Firas Kassab

8. • Effective against more gram negative rods than penicillin
• Amoxycillin is better absorbed from the GI tract than ampicillin (i.e food
doesnot interfere with absorption of amoxicillin)
• Cap .Amoxicillin -250mg/500mg Tid x 5 days
Dr.Firas Kassab

9. • Clavulanic acid- inhibits β lactamase enzymes
• In combination with amoxycillin –
Destroys organisms that are resistant to amoxycillin because of their
beta-lactamase production
e.g. species of staphylococci, nonhemolytic streptococci and some
gram negative bacteria
 Amoxycillin (500 mg or 750 mg or 1000mg) + clavulanic acid (125
mg) = Cap. Augmentin
Dr.Firas Kassab

10. Based on their activity against Gram negative organisms:
1ST GENERATION CEPHALOSPORINS
• Active against gram positive cocci, E.coli, Kliebsella,etc
• Ex: Cephalexin (Keflex)
2ND GENERATION CEPHALOSPORINS
• Broader activity against gram negative bacteria
• Increased activity against the anaerobic bacteria
• Ex: Cefuroxime
Dr.Firas Kassab

11. 3RD GENERATION CEPHALOSPORINS
• More activity against Gram negatives.
• Less active against gram positive cocci
• Ex: Cefoperazone, Ceftriaxone, and Cefotaxime
 Oral Cephalosporins effective in odontogenic infections
Cephalexin (keflex)
Cefadroxil (Duricef)
 Not the drug of choice, used only in certain situations (bactericidal activity)
 Patients who are allergic to penicillin drugs should be given the
cephalosporin antibiotic with caution.
Dr.Firas Kassab

12. USES
• Against Gram positive and gram negative aerobic and
anaerobic bacteria.
• Alternative to penicillin in patients allergic to penicillin
• Alternative to tetracycline in pregnancy
SIDE EFFECTS
• Cholestatic Jaundice – with erythromycin estolate
• Ototoxic in high doses
Dose – 250 -500 mg three to four times in a day for 5 days
Other macrolides - Azithromycin, clarithromycin
Dr.Firas Kassab

13. • USES
Same as erythromycin
• SIDE EFFECTS
Pseudo- membranous colitis (gastrointestinal toxicity)
Dose : 150-300 mg every 6 hour
Prophylaxis of endocarditis (Adult) : 600 mg 1 hr before the
dental procedure
Dr.Firas Kassab

14.  Bactericidal
 Use is limited to anaerobic organisms.
 No effect on aerobic bacteria such as streptococci
 Uses :
 Periodontal disease therapy
 Anaerobic odontogenic infections
 Used either alone or in combination with antibiotics like amoxycillin
(Against aerobic)
Dr.Firas Kassab

15. Side Effects Of Metronidazole:
• Causes an antabuse reaction.
• Produces metallic taste in the mouth.
• Peripheral neuropathy, seizures and ataxia have been seen with
prolonged use.
• Dose: 250 – 500 mg Tid for 5 days
Dr.Firas Kassab

16. • principle 1:
To determine the presence of infection
• principle 2:
Choose the appropriate antibiotic
• principle 3:
Proper antibiotic administration
Dr.Firas Kassab

17. Dr.Firas Kassab

18. (a) Complete history
• patient’s symptom
• Clinical examination
(pain, swelling, surface erythema, pus formation, limitation
of motion, fever, lymphadenopathy, toxic appearance)
• If infection present, determine the severity of infection
Dr.Firas Kassab

19. (b) COMPROMISED HOST DEFENSES
1 - Uncontrolled metabolic diseases
2 - Immunosupressants
1.Decreased function of leucocytes
2.Decreased chemotaxis
3.Decreased phagocytosis
4.Decreased antibody synthesis
5.Decreased bacterial killing
When a patient’s defenses are impaired, antibiotics play a more
important role in the control of infection
Dr.Firas Kassab

20. (c ) TO TREAT INFECTION SURGICALLY
GOALS :
1. To remove the cause of infection
2. To provide drainage of accumulated pus and necrotic
debris
MODES :
1.Endodontic treatment
2.Extraction
3.Incision and drainage + extractionendodontic
treatment
Drainage of pus
Dr.Firas Kassab

21. • Reasons for failure of antibiotics in presence of
infection:
• Antibiotics do not diffuse well in to the infected areas
• Some antibiotics - inactive at acidic pH.
• High levels of antibiotic inhibitors - present.
Dr.Firas Kassab

22. Dr.Firas Kassab

23. Scientifically determined in the laboratory, where the
organism can be isolated from pus, blood or tissue
or
Empirically based upon the knowledge of the
pathogenesis and clinical presentation of specific
infections.
• Antibiotic therapy is then either initial or definitive,
depending on whether the organism is even identified
precisely
Dr.Firas Kassab

24. • Non-responsive infection
• Postoperative wound infection
• Recurrent infection
• Suspected actinomycosis and osteomyelitis.
• Compromised host defenses
Dr.Firas Kassab

25.  As effective as broad spectrum antibiotics
 Maintains the normal host microflora
 No chance of occurrence of bacterial resistance
Dr.Firas Kassab

26. • Instead of bacteriostatic antibiotic
• Advantages of bactericidal antibiotic are:
• Less reliance on host resistance
• Killing of the bacteria by the host itself
• Faster results than with bacteriostatic drugs
Dr.Firas Kassab

27. Dr.Firas Kassab

28. • Dose should be sufficient to achieve desired therapeutic effect
without causing any harm to the host
• The dosage prescribed should be establish a concentration of
blood that is 3 -4 times the MIC (minimum inhibitory
concentration)
Dr.Firas Kassab

29. • Each antibiotic has an established plasma half life (t1/2), during
which one half of the absorbed dose is excreted
• The usual dosage interval for the therapeutic use of antibiotics
is 4 times the t1/2.
• For ex: the half life for amoxicillin is 2 hours. Thus the interval
between the doses should be_____
Dr.Firas Kassab

30. • BASED ON BODY SURFACE AREA
Individual dose = BSA[m2] x adult dose
1.7
• BASED ON BODY WEIGHT
Individual dose = BW[kg] x average
70 adult dose
Dr.Firas Kassab

31. YOUNG’S FORMULA :
CHILD DOSE = Age x adult dose
Age + 12
DILLING’S FORMULA :
CHILD DOSE = Age x adult dose
20
Dr.Firas Kassab

32. FOUR CATEGORIES BASED ON HOW SAFE OR RISKY
TO USE
Category A – No evidence of fetal harm.
Eg : Nystatin
Category B – No known association with birth defects
- animal studies
Eg : Amoxicillin, Augmentin, Metronidazole,
Cephalosporins.
Category C – Information only from animal studies high risk
Eg :Vancomycin,fluoroquinolones
Category D – Evidence of human risk.
Eg : Tetracyclines, aminoglycosides, sulfa drugs.
Dr.Firas Kassab

33. Combination therapy with two or more
antibiotics is used in special cases:
• Prevent the emergence of resistant strains
• To treat emergency cases during the period when an
etiological diagnosis is still in progress
• To take advantage of antibiotic synergism
Dr.Firas Kassab

34. Advantages
• Broad antibacterial spectrum
• Reduced dose for each
agent.
• Antibiotic synergism
• Decreased adverse drug
reactions
Disadvantages
• Antibiotic antagonism
• Increased financial costs
• Greater microbial resistance
• Resistance genes
• Increased risk of superinfection
• Greater likelihood of adverse
reactions
Dr.Firas Kassab

35. 1. Failure to surgically eradicate - source of infection
2. Too low - blood antibiotic concentration
3. Inability to penetrate the site of infection
4. Impaired host defenses
5. Patient failure to take the antibiotic
6. Inappropriate choice of antibiotic
7. Limited vascularity or blood flow
8. Decreased tissue pH or oxygen tension
9. Antibiotic resistance
10. Delay or incorrect diagnosis
11. Antibiotic antagonism
Dr.Firas Kassab

36. Dr.Firas Kassab

37. Analgesics are divided into two groups:
a. Opioid/ Narcotic/ Morphine like analgesics
b. Nonopoid/ Non-Narcotic/ Aspirin like Antipyretic
or Anti-inflammatory type analgesics.
Dr.Firas Kassab

38. The analgesic action of the morphine is primarily
through the action on the CNS.
They are strong analgesics.
They relieve visceral pain better than the somatic
pain.
Dr.Firas Kassab

39. All drugs grouped in this class have analge sic, Antipyretic
and Anti-inflammatory actions in different measures.
They act primarily on peripheral pain mechanisms but also in
CNS to raise the pain threshold.
Compared to OPOIDS they are weaker analgesics (except for
inflammatory pain); do not depress CNS, do not produce
physical dependence and have no abuse liability
Dr.Firas Kassab

40. A. Nonselective COX inhibitors (conventional
NSAIDs)
1. Salicylates: Aspirin, Diflunisal, salsalate
2. Pyrazolone derivatives: Phenylbutazone,
Oxyphenbutazone, metamizol (dipyrone)
3. Indole derivatives: Indomethacin, Sulindac.
4. Propionic acid derivatives: Ibuprofen,
Naproxen,Ketoprofen, Flurbiprofen..
Dr.Firas Kassab

41. 5. Anthranilic acid derivative: Mephenamic
acid
6.Aryl-acetic acid derivatives: Diclofenac, suldinac,
Indomethacin, Tolmetin.
7.Oxicam derivatives: Piroxicam, Tenoxicam.
8. Pyrrolo-pyrrole derivative: Ketorolac.
B. Preferential COX-2inhibitors –
Nimesulide, Meloxicam, Nabumetone
Dr.Firas Kassab

42. C. SelectiveCOX-2inhibitors –
Celecoxib, Rofecoxib, Valdecoxib
D. Analgesic-antipyretics with poor anti-inflammatory
action
1. Paraaminophenol derivative: Paracetamol
(Acetaminophen).
2. Pyrazolone derivatives: Metamizol (Dipyrone),
Propiphenazone.
3. Benzoxazocine derivatives: Nefopam
Dr.Firas Kassab

43. Most NSAIDs act as non-selective inhibitors of the enzyme
cyclooxygenase, inhibiting both,the cyclooxygenase-1
(COX-1) and cyclooxygenase-2 (COX-2) isoenzymes.
Cyclooxygenase catalyses the formation of prostaglandins
and thromboxane from arachidonic acid
Dr.Firas Kassab

44. Dr.Firas Kassab

45. NSAIDs cannot be used (are contraindicated) in the following
cases:
• Allergy to aspirin or any NSAID.
• Aspirin should not be used under the age of 16 years.
• During pregnancy.
• During breast feeding.
• On blood thinning agents (anticoagulants).
• Suffering from a coagulation defect.
• Active peptic ulcer.
Dr.Firas Kassab

46. IBUPROFEN:
Gastric discomfort, nausea and vomiting, less than aspirin or
indomethacin, are the most common side effects.
Precipitates aspirin induced asthma.
They are not to be prescribed to pregnant women, peptic
ulcer patients and asthmatic patients
Dosage - 400 mg tid
Dr.Firas Kassab

47. DICLOFENAC SODIUM
An analgesic-antipyretic, anti-inflammatory drug, similar in
efficacy to naproxen.
It has short lasting antiplatelet action
It has good tissue penetrability and concentration in synovial
fluid is maintained for 3 times longer period than in plasma,
exerting extended therapeutic action in joints.
Dose : 50 mg Bid /Tid
Dr.Firas Kassab

48. PARACETAMOL (ACETAMINOPHEN)
Actions:
Good and promptly acting antipyretic
Has negligible anti-inflammatory action.
Gastric irritation is insignificant : mucosal erosion and
bleeding occur rarely only in overdose.
It does not affect platelet function or clotting factors
Dr.Firas Kassab

49. Uses of paracetamol:
 ‘Over the counter’ analgesic for headache, musculoskeletal pain,
where the antiinflammatory action is not required.
 One of the best used antipyretics.
 Can be used in all age groups(infants to elderly),
pregnant/lactating women, in presence of the other disease states
and in patients in whom aspirin is contraindicated.
Adverse effects:
In antipyretic doses, paracetamol is safe and well tolerated.
Nausea and rashes occur occasionally, leukopenia is rare.
Dr.Firas Kassab

50. NSAIDs are effective for treating acute pain and inflammation
related to
Minor and major oral surgicalprocedures.
Restorative procedures.
Periodontal surgical and non-surgical procedures.
Endodontic procedures such as root canal thrapy, endodontic
surgical procedures, post and core,etc.
Chronic pain related to the dental procedures.
Dr.Firas Kassab

51. Factors affecting the initial selection of the drug are:
1. The nature of problem (acute/chronic;
pain : inflammation ratio; severity of problem)
2. Risk factors
3. Possible drug interactions
Dr.Firas Kassab

52. Other factors to be considered are:
• Mild to moderate pain with little inflammation –
paracetamol or low dose ibuprofen.
• Acute musculoskeletal pain, osteoarthritic, injury associated
inflammation. – Diclofenac sodium
• Postoperative or other acute but short lasting painful
conditions with minimal inflammation – keterolac, nefopam
Dr.Firas Kassab

53. • Gastric intolerance to conventional NSAID – Rofecoxib,
Celecoxib.
• Exacerbation of rheumatoid arthritis, ankylosing spondylitis,
acute gout, acute rheumatic fever – high dose Aspirin,
Indomethacin, Naproxen, Piroxicam.
• Patients with history of asthma or anaphylactoid reactions to
aspirin and other NSAIDs – Nimesulide.
• Combination therapy if used should be limited to short
periods only.
Dr.Firas Kassab

54. Dr.Firas Kassab