Groups of antibiotics with their explaination

1. ANTIBIOTICS
KWIHANGANA GERALD
JSNM

2. Definition and overview
Antibiotics
 A substance obtained from the living micro-
organisms that can be used to kill or inhibit growth
of micro-organisms.
Antibacterial
 Drugs used to treat bacterial infections.
 In practice, they are called antibiotics
 Antibiotics are among the most commonly used
and misused drugs in Uganda.

3. Selective toxicity
 Selective toxicity refers to the ability of the
antibiotic to kill harmful bacteria without
damaging the host cells.
 Antibiotics exhibit selective toxicity.
Antibacterial spectrum
 This is the range of activity against bacteria
(micro-organisms).
 Antibiotics may have a broad or narrow
spectrum of activity.

4. Broad spectrum antibiotics
 Broad spectrum antibiotics are effective (kill or
inhibit) a wide range of bacteria.
 They are effective against gram –ve and gram
+ve bacteria.
 Broad spectrum antibiotics are commonly used
in mixed infections or empirical therapy.
 They are commonly associated with super
infections as a result of disturbance of normal
flora.

5. Broad spectrum- Examples
 Amoxicillin
 Ampicillin
 Doxycycline
 Tetracycline
 Ceftriaxone
 Erythromycin
 Ciprofloxacin
 Cephalexin

6. Narrow spectrum antibiotics
 Narrow spectrum antibiotics are effective against
a small range of bacteria.
 They are recommended when the causative
bacteria are known (definitive therapy).
 Blood culture and sensitivity investigations
guide on the selections of these antibiotics.

7. Mode of action of antibiotics
 Antibiotics can be classified as bacteriostatic or
bactericidal.
 The severity of the infection and status of the
immune system of the patient guide on the
choice of antibiotics.
 Bactericidal antibiotics are recommended for
severe infections and in immunosuppressed
patients.

8. Bacteriostatic antibiotics
 Bacteriostatic antibiotics inhibit the growth or
multiplication of bacteria.
 Bacteriostatic antibiotics may become
bactericidal depending on the dose and type of
bacteria.
 These antibiotics need the support of the
immune system to clear the bacterial infection.

9. Bacteriostatic antibiotics- Examples
 Tetracyclines (doxycycline, minocycline)
 Macrolides (erythromycin, azithromycin)
 Sulphonamides (sulphadimidine)
 Chloramphenicol

10. Bactericidal antibiotics
 Bactericidal antibiotics kill the bacteria
immediately.
 They are highly recommended in severe
infections and immune suppressed patients.
 These antibiotics do not need support from the
immune system.

11. Bactericidal antibiotics - examples
 Penicillins (amoxicillin, benzylpenicillins)
 Cephalosporins (cephalexin, ceftriaxone)
 Aminoglycosides (gentamycin, amikacin)
 Quinolones (ciprofloxacin, moxifloxacin,
ofloxacin)

12. Antibacterial resistance
 Antibiotic resistance refers to the reduction of
effectiveness of antibiotics to particular bacteria.
 Cross resistance may occur for antibiotics that
have a similar mode of action.
 Antibiotic resistance may be natural or acquired.
 Culture and sensitivity is used to determine the
possibility of antibiotic resistance.
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13. Natural antibiotic resistance
 This type of antibiotic resistance occurs without
previous exposure to antibiotics.
Example
 Ciprofloxacin is not naturally effective against
streptococcus pneumoniae.
 Psuedomonas aeruginosa is resistant to
penicillin G.
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14. Acquired antibiotic resistance
 This type of antibiotic resistance occurs to
antibiotics which were previously effective against
particular bacteria.
 Acquired resistance is caused by previous
exposure to antibiotics.
Example
 Ciprofloxacin was previously effective
N.gonorrhoeae.
 Staph.aureus was previous sensitive to penicillin
G.

15. Mechanism of antibiotic resistance
 Inactivation of the antibiotic by bacterial
enzymes
 Bacteria produce a penicillinase enzymes that destroy some
penicillins
 This can be prevented by use of betalactimase inhibitors e.g.
clavulanic acid
 Decreased binding of the antibiotics to target
molecules.
 Some bacteria may change the site of action e.g. penicillin
binding protein where antibiotics like penicillins bind in order to
kill the bacteria.
 Decreased accumulation of the drug by
bacteria

16. Ways of preventing antibiotic
resistance
 Proper selection of antibiotics effective against
bacteria.
 Use of combination antibiotic therapy e.g. in T.B
treatment.
 Use of culture and sensitivity test before giving
antibiotics.
 Giving antibiotics for the right period of time and
correct dose.

17. Indications of antibiotics
 Definitive therapy
 Empirical therapy
 Surgical prophylaxis

18. Definitive therapy
 Definitive therapy is recommended when the
causative organism is identified.
 Culture and senstivity is used to identify the
causative bacteria.
 Targets cure of an established bacterial infection.
 Narrow spectrum antibiotics are usually
recommended.
 Definitive therapy is rarely used in primary care
setting.

19. Empirical therapy
 Antibiotics are recommended on best guess.
 Broad spectrum antibiotics/combination therapy
are employed.
 Choice of antibiotic is based on local sensitivity
pattern.
 Empirical therapy is the most commonly
employed approach in Uganda due to lack of
sufficient lab facilities.

20. Antibiotic combinations
 This is the use of more than one antibiotic at
ago in the treatment of bacterial infection.
 It is commonly used in diseases such as
tuberculosis, pelvic inflammatory disease and
septicemia.
 Antibiotic combinations usually result into
increased side effects and costs.

21. Importance of antibiotic combination
 Prevention of antibiotic resistance e.g. in TB
treatment
 Treatment of mixed infections e.g. in PID
 Decrease antibiotic toxicity by using each
antibiotic in a lower dose.
 To enhance antibiotic action e.g. gentamycin +
benzylpenicillin in the treatment of septicemia.

22. Disadvantages of antibiotic
combination
 Antibiotic combination increases the risk of
adverse effects.
 It increases the risk of supra infections e.g.
vaginal candidiasis.
 It increases the cost of antibiotic treatment.
 It may result into antibiotic antagonism (drug
interaction).

23. Surgical prophylaxis
 Antibiotics are administered to the patient prior
to surgical procedure.
 Surgical prophylaxis is intended to prevent post
operative wound infection.
 Widely used on surgical wards in hospitals.
 Single dose of an effective antibiotic is preferred.
 2nd dose may be given in case of delay in
surgical procedure.
 Antibiotics such as cefazolin, ceftriaxone and
clindamycin are commonly used.

24. Clinical uses of antibiotics

25. Factors to consider in antibiotic
selection
Spectrum of activity
 The selected antibiotic should be able to cover the
suspected range of bacterial pathogens.
Tissue penetration
 Antibiotics should be able to reach the site of infection in
good concentration.
Consider the following:
 Adequacy of blood supply e.g. diabetic foot.
 Presence of abscess that require draining.
 Chronic infections e.g. chronic prostatitis

26. Cont’d…
Antibiotic resistance
 Some antibiotics have developed resistance to
common bacterial pathogens.
 Use the local sensitivity pattern to help in the
antibiotic selection.
 Ciprofloxacin has developed resistance to
N.gonorrhoeae up to 96% in Uganda.
Antibiotic safety profile
 If possible use antibiotics with mild side effects .

27. Cont’d…
Patient factors e.g. Pregnancy status, age of the patient &
known allergy to a particular antibiotic.
 Some antibiotics are not recommended during pregnancy,
breast feeding or children.
Physiological function of organs
 Consider liver and kidney function
 Antibiotics excreted through urine may need to be avoided or
adjustment of the dose in case of renal impairment.
Cost of the antibiotic
 Recommend a cost effective antibiotic to the patient.

28. Cont’d…
Patient compliance
 Poor patient compliance with antibiotics given 6hourly or
8 hourly may lead to treatment failure.
 Recommend an antibiotic that can be given once or twice
daily if possible.
Route of administration
 Injectable antibiotics are recommended for severe
infections.
 Switch to oral therapy after clinical improvement (average
72 hours).
 Oral route is recommended for mild to moderate

29. Common Causes of antibiotic failure
 Antibiotic resistance
 Incorrect diagnosis
 Wrong dose and duration of antibiotics
 Poor penetration to the site of infection e.g.
presence of pus.
 Poor quality of antibiotics
 Poor patient compliance
 Inadequate coverage of pathogens
 Drug interaction

30. Common antibiotics
 Penicillins
 Cephalosporins
 Macrolides
 Quinonoles
 Tetracyclines
 Aminoglycosides
 Sulphonamides

31. Beta lactam antibiotics
 Beta lactam antibiotics are antibacterials that
contain beta lactam ring in their structure.
 The beta lactam ring is responsible for the
antibacterial effect.
 Modification of the beta lactam ring determines:
 Spectrum of activity
 Beta lactamase stability
 Pharmacokinetic profile

32. Beta lactam antibiotics - Examples
 Penicillins
 Cephalosporins
 Carbapenems

33. Penicillins
 Penicillins belong to beta lactam antibiotics.
 They are available as natural and semi-
synthetic drugs.
 Penicillins are the most widely used antibiotics
in Uganda.
 This is because of their availability, low cost
and their good safety profile.
 Penicillins were introduced in 1940 but wide
use started in 1945.

34. Mode of action of penicillins
 Penicillins are bactericidal in action.
 They act by inhibiting the cell wall synthesis of
the susceptible bacteria.
 This weakens the cell wall causing bacteria to
take up excessive water leading to cell lysis.
 Penicillins are effective against bacteria that are
rapidly multiplying.

35. Classification of penicillins
EXAMPLES
CLASS
Penicillin –V (Phenoxymethyl penicillin)
Penicillin-G (Benzylpenicillin)
Natural penicillins
Penicillin G Benzathine
Penicillin G Procaine
Repository forms of penicillin G
Cloxacillin
Flucloxacillin
Resistant to degradation by penicillinase.
Useful for treating S. aureus infections
Penicillinase resistant penicillins
Ampicillin
Amoxycillin
Amoxycillin plus clavulanic acid
Broad spectrum penicillins
(Aminopenicillin)

36. Natural penicillins
Examples
Penicillin –V (Phenoxymethyl penicillin)
Penicillin-G (Benzyl penicillin)
 They are effective against gram +ve nd some
gram –ve bacteria.
 Natural penicilins are hydrolyzed by
penicillinase enzymes therefore not
recommended for Staph.aureus.

37. Cont’d…
 Penicillin G is a acid labile therefore available in
injectable form (IM/IV).
 Penicillin V is more stable to gastric acid
therefore can be given in form of tablets/oral
suspension.

38. Route of administration
Drug Dosage form Route of
administration
Benzylpenicil
lin
Powder for
injection 600mg
IM/IV
Penicillin V Powder for oral
suspension
125mg/5ml
Tablets 250mg
Oral

39. Spectrum of activity
 Streptococcus pneumoniae
 Streptococcus viridans
 Neisseria meningitidis
 Clostridium perfringens
 Treponema pallidum
Note
 Natural penicillins are not effective against
penicillinase producing bacteria e.g.
Staph.aureus.

40. Clinical uses
 Pneumonia
 Meningitis
 Neuro syphilis
 Tonsilitis/pharyngitis
 Infectious endocarditis
 Tetanus

41. Broad spectrum penicillins
(aminopenicillins)
Example
Amoxicillin
Ampicillin
 Aminopenicillins are broad spectrum penicillins
effective against gram +ve and gram –ve bacteria.
 Amoxicillin and ampicillin both have same
spectrum of activity.
 Amoxicillin is preferred because it is well absorbed
compared to ampicillin when given orally.
 It also causes less diarrhoea since it is completely
absorbed.

42. Cont’d…
 Aminopenicillins are inactivated by penicillinase
producing bacteria.
 Because of this, they are not effective in treating
infections caused by Staph.aureus.

43. Route of administration
Drug Dosage form Route of
administration
Amoxicillin Capsules 250mg, 500mg
Powder for oral suspension
125mg and 250mg/5ml
Powder for Injection 500mg
Oral
IV
Co-amoxiclav Powder for oral suspension
228mg/5ml
Tablets 625mg, 1g
Powder for injection 600mg
Oral
IV
Ampicillin Capsules 250mg
Powder for oral suspension
125mg/5ml
Powder for injection 500mg
Oral
IV

44. Spectrum of activity
 . Aminopenicillins
Gram +ve bacteria
Streptococcus pneumoniae
L.monocytogenes (ampicillin)
Gram -ve bacteria
H.influenzae
E.coli
P.mirabilis
salmonella sp
Shigella sp
N.gonorrhoeae
H.pylori (amoxicillin)

45. Beta lactamase inhibitors
Clavulanic acid
Salbactam
Tazobactam (not currently used in Uganda)
 Some bacteria e.g. staph.aureus produce beta
lactamase enzyme which destroys penicillins.
 Beta lactamase inhibitors prevent these bacteria from
destroying penicillins thus extending their spectrum.
 Beta lactamase inhibitors have no clinical uses but
the combination widens the spectrum of activity of
amino penicillins.

46. Combinations
 Amoxicillin + clavulanic acid
 Ampicillin + salbactam
 Piperacillin + tazobactam

47. Clinical uses
 Pneumonia
 Typhoid
 Urinary tract
infections
 Otitis media
 Listeria meningitis
(ampicillin)
 Dental abscess
 Sinusitis
 Eradication of H-
pylori bacteria in
PUD Osteomyelitis
(co-amoxiclav)

48. Penicillinase resistant penicillins
Examples: Cloxacillin,Flucloxacillin
 These antibiotics have a narrow spectrum of
activity.
 They were developed to target penicillinase
producing bacteria especially Staph.aureus.
 Cloxacillin and flucloxacillin have the same
spectrum of activity.
 Flucloxacillin is preferred because it is well
absorbed when given orally compared to

49. Route of administration
Drug Dosage form Route of
administration
Cloxacillin Capsules 250mg
Oral suspension 125mg
Power for Injection
500mg
Oral
IM/IV
Flucloxacillin Capsules 250mg
Oral suspension 125mg
Power for Injection
500mg
Oral
IM/IV

50. Combinations
 Cloxacillin and flucloxacillin have a narrow
spectrum of activity.
 They are usually combined with either ampicillin
or amoxicillin.
 The combination is intended to widen the
spectrum of both drugs
 Ampicillin + Cloxacillin (Ampiclox)
 Amoxicillin + Flucloxacillin (Flucamox)

51. Clinical uses of combinations
 Osteomyelitis
 Septicemia
 Pneumonia
 Cellulitis
 Impetigo
 Wound infection
 Urinary tract infections due to Staph.aureus

52. Repository forms of penicillins
Penicillin G Benzathine
Penicillin G Procaine
 This class are obtained by combining
benzypenicillin and insoluble compounds like
benzathine or procaine.
 The combination results in slow absorption and
prolonged plasma drug concentration.
 Benzathine penicillin is administered once a week
and procaine penicillin once a day.
 All repository forms of penicillins should be given by
I.M route.

53. Route of administration
Drug Dosage form Route of
administration
Benzathine penicillin
G
Powder for
injection 2.4MU
IM
Procaine penicillin G Powder for
injection 4 MU
IM

54. Spectrum of activity
 Streptococcus pyogenes
 Treponema pallidum

55. Clinical uses
 Pharyngitis
 Rheumatic fever
 Syphilis
 Pneumonia (procaine penicillin)

56. Pharmacokinetics of penicillins
 Ampicillin and cloxacillin are poorly absorbed
when administered orally.
 Presence of food in the GIT decreases the
absorption of ampicillin and cloxacillin therefore
give on empty stomach at least 1 hour before
food.
 Amoxicillin, flucloxacillin are well absorbed and
food doesn’t affect their absorption.
 Penicillins are distributed to most body tissues
and fluids.

57. Cont’d…
 Penetration of meninges and fluids of joints is
poor unless there is inflammation.
 Metabolism of penicillins is minimal and most
drugs are excreted through urine in active
form.
 Renal impairment may interfere with excretion
of penicillins leading to accumulation in the
body.
 Dosage adjustment in this case may be
necessary.

58. Side effects
 Penicillins are well tolerated and are among the
safest antibiotics.
Common side effects include:
 Urticaria
 Skin rashes
 Pruritus (itching of the skin)
 Pain at injection site
 Diarrhoea
 Nausea and vomiting
 Vaginal candidiasis (super infection)

59. Drug interactions
 Penicillins may decrease effectiveness of oral
contraceptives.
 Penicillins and aminoglycosides may
inactivate each other when mixed in the same
syringe or IV solution.
Note
 Never mix penicillins and aminoglycosides
like gentamycin in the same syringe

60. Contraindications
 Penicillins are contraindicated in patients with
known hypersensitivity.
Pregnancy and breast feeding
 Penicillins can be used safely during
pregnancy and breast feeding though it
appears in breast milk but in small amounts.

61. Cephalosporins
 Cephalosporins are broad spectrum semi-
synthetic antibiotics.
 They share the same structure and mode of
action with penicillins.
 Cephalosporins are more stable/resistant to
beta lactamase producing bacteria compared
to penicillins.
 They are classified into generations
depending on their spectrum of antibacterial
activity.

62. Mode of action
 Cephalosporins are bactericidal against
susceptible bacteria in action.
 They inhibit the cell wall synthesis by binding to
penicillin binding proteins (PBP).
 This results into damage to the cell wall causing
lysis and death of bacteria.

63. Classification of Cephalosporins
 First generation
 Second generation
 Third generation
 Fourth generation

64. First generation- examples
 Cephalexin
 Cephadroxil
 Cephradine
 Cefazolin

65. First generation cephalosprins
 This class of cephalosporins is effective against
gram +ve bacteria and have limited activity against
gram -ve.
 First generation cephalosporins have similar
spectrum of activity and can be used
interchangeably.
 These antibiotics are the most effective against
Staph.aureus and streptococci.
 They are recommended in the treatment of
bacterial infections affecting the respiratory tract,

66. Route of administration
Drug Dosage form Route of
administration
Cephalexin Capsules 250mg, 500mg
Powder for oral suspension
125mg/5ml, 250mg/5ml
Oral
Cephadroxil Tablets 250mg,500mg
Powder for oral suspension
125mg/5ml, 250mg/5ml
Oral
Cephradine Capsules 250mg, 500mg
Powder for oral suspension
Oral
Cefazolin Powder for injection 500mg,
1g
IV/IM

67. Spectrum of activity
First generation cephalosporins
Gram –ve bacteria
E.coli
P.miribalis
Klebisella.pneumoniae
Gram +ve bacteria
Staph.aureus
Staph.epidermidis
Strep.pneumoniae
Strep.pyogenes

68. Note
First generation Cephalosporins are not effective
against:
 Haemophilus influenzae
 Pseudomonas spp
 Proteus spp
 Anaerobic bacteria such as bacteroides fragilis

69. Clinical uses
 Pneumonia
 Sinusitis
 Otitis media
 Septic arthritis
 Osteomyelitis
 Mastitis
 Urinary tract
infections
 Surgical prophylaxis
 Tonsillitis
 Chronic bronchitis
 Cellulitis

70. Second Generation Cephalosporins -
examples
 Cefuroxime
 Cefaclor
 Loracarbef
 Cefamandole
 Cefprozil
 Cefoxitin

71. Second Generation Cephalosporins
 They have enhanced activity against gram –ve
bacteria.
 Are less active against gram +ve than first
generation.
 Cefuroxime has greater activity against
H.influenzae and N.gonorrhoeae.
Note: Second generation Cephalosporins are
inactive against pseudomonas.

72. Route of administration
Drug Dosage form Route of
administration
Cefaclor Capsules/tablets 375mg
Powder for oral suspension
125mg/5ml
250mg/5ml
Oral
Cefuroxime Tablets 250mg, 500mg
Powder for oral suspension
125mg/5ml
Powder for injection 750mg,
1.5g
Oral
IM/IV
Loracarbef Oral
Edco International Ltd

73. Spectrum of activity
Second generation
cephalosporins
Gram –ve
E.Coli
Proteus. Mirabilis
H.Influenzae
N.Gonorrhoeae
Klebsiella.pneumoniae
Gram +ve
Strep.pneumoniae
Strep.pyogenes
Bacteroides sp
Edco International Ltd

74. Clinical uses
 Pneumonia
 Acute otitis media
 Chronic bronchitis
 Pelvic inflammatory disease
 Tonsillitis
 Surgical prophylaxis
 Gonorrhoea
 Bacterial meningitis
Edco International Ltd

75. Third Generation Cephalosporins
 This group of penicillins have a broad spectrum
of activity against gram –ve and gram +ve
bacteria.
 They are commonly employed in empirical
therapy.
 Gram positive activity is decreased compared to
first and second generation.
 Gram negative activity is enhanced to cover a
wider range of bacterial pathogens.

76. Third Generation Cephalosporins-
examples
Oral Injectable
Cefixime
Cefpodoxime
Cefdinir
Ceftriaxone
Cefotaxime
Ceftazidime
Cefoperazone

77. Third Generation Cephalosporins
 Have greater activity against a wide range of
gram -ve and some gram +ve bacteria.
 Cefixime has no activity against Staph.aureus.
therefore should not be used in the treatment of
skin and soft tissue infection.
 Ceftazidime and Cefoperazone are the only third
generation effective against P.aeruginosa.

78. Route of administration
Drug Dosage form Route of
administration
Ceftriaxone Powder for Injection
500mg, 1g, 2g
IM/IV
Cefotaxime Powder for injection
500mg, 1g, 2g
IM/IV
Cefixime Tablets 100mg, 200mg,
400mg
Powder for oral
suspension 100mg/5ml
Oral

79. Cont’d…
Cefpodoxime Tablets 200mg
Powder for oral
suspension
100mg/5ml
Oral
Cefdinir Capsules 300mg Oral
Ceftazidime Powder for injection
500mg, 1g
IM/IV

80. Spectrum of activity
Third generation
cephalospsorins
Gram -ve
E.coli
H.Influenzae
P.mirabilis
Pseudomonas aureginosa
N.meningitides
N.gonorrhoeae
H.ducreyi
Enterobacteriacae
Gram +ve
Strep.pneumoniae
Strep.pyogenes
Anaerobic streptococci

81. Clinical uses
 Bacterial meningitis
 Urinary tract
infections
 Gonorrhoea
 Pneumonia
 Chancroid
 Bacterial
endocarditis
 Surgical prophylaxis
 Osteomyelitis
 Brain abscess
 Septicemia
 Pelvic inflammatory
disease
 Cellulitis

82. Fourth Generation Cephalosporins
 Fourth generation have a broader spectrum of
activity compared to third Generation.
 Gram positive activity is wider compared to third
generation.
 Have a wider spectrum of activity against gram
–ve bacteria including pseudomonas.
 They are more resistant to inactivation by
betalactamase enzymes.

83. Fourth Generation Cephalosporins -
examples
 Cefepime
 Cefeperoxime

84. Pharmacokinetics
 Most cephalosporins are not absorbed well when
given orally and are only given by injection.
 Oral cephalosporins are well absorbed when
taken orally though food delays but doesn’t affect
the total amount of drug absorbed.
 Cephalosporins penetrate well into most body
fluids and ECF of most tissues especially when
inflammation is present.

85. Cont’d…
 Ceftriaxone, cefotaxime, ceftazidime, cefepime
enter the CSF in high concentration and can be
used in the treatment of meningitis.
 Most cephalosporins are excreted mainly in urine
in unchanged form therefore dosage adjustment
may be required in renal impairment.
 Ceftriaxone and cefoperaxone are excreted
primarily in bile therefore their use doesn’t require
dosage adjustment in renal impairment.

86. Side effects
 Diarrhoea
 Vomiting
 Headache
 Nausea
 Abdominal
discomfort
 Rashes
 Urticaria
 Pain at injection site
 Nephrotoxicity

87. Contraindications
 Known hypersensitivity to cephalosporins or
penicillins.
Breast feeding and pregnancy
 Cephalosporins can be used safely during
pregnancy.
 Use of cephalosporins with caution during breast
feeding since it enters breast milk in significant
amount and may alter the bowel flora of the
infant.

88. Macrolides
 Macrolides have an antibacterial spectrum
similar to benzylpenicillin.
 They are recommended for patients who are
allergic to penicillins.
 Macrolides do not penetrate the CNS therefore
cannot be used in the treatment of meningitis.

89. Macrolides- examples
 Erythromycin
 Azithromycin
 Clarithromycin
 Roxithromycin

90. Mode of action
 Macrolides are primarily bacteriostatic
antibiotics.
 They can become bactericidal depending on the
bacterial pathogen and the dose given.
 Macrolides inhibit bacterial protein synthesis by
binding to the 50s ribosome sub unit.
 This results into inhibition of RNA dependent
protein synthesis.

91. Route of administration
Drug Dosage form Route of
administration
Erythromycin Tablets 250mg
Powder for oral suspension 125mg/5ml
Eye ointment
Oral
Topical
Azithromycin Tablets/capsules 250mg, 500mg
Powder for oral suspension 200mg/5ml
Oral
Clarithromycin Tablets 250mg, 500mg
Powder for oral suspension 125mg/5ml
Oral
Roxithromycin Tablets 150mg Oral

92. Spectrum of activity
 Strep.pneumoniae
 Strep.pyogenes
 Staph.aureus
 Mycoplasma
pneumoniae
 Chlamydia
trachomitis
 Legionella sp
 M.catarrhalis
 H.Influenzae
 Tryponema pallidum
 H.pylori
 Paropionibacterium
acne
 Mycobacterium
avium complex
 Bordetella pertusis

93. Macrolides- special features
 Erythromycin is the most effective against
Staph.aureus among the macrolides.
 Azithromycin and clarithromycin are less active
against Streptococci and Staph.aureus.
 Azithromycin & clarithromycin have enhanced
activity against H.influenzae and M.catarrhalis
compared to erythromycin.
 Azithromycin and clarithromycin are effective
against mycobacterium avium complex.

94. Clinical uses
 Pneumonia
 Sinusitis
 Tonsillitis
 Otitis media
 Syphilis
 Non gonococcal
urethritis
 Trachoma
 Acne vulgaris
 Mycobacterium
avium complex
infection
 Typhoid
 Eradication of
H.pylori bacteria

95. Pharmacokinetics
Clarithromycin
 It is rapidly absorbed from the GIT, undergoes
first pass metabolism which decreases its
bioavailability, widely distributed in body tissues
and fluids and metabolized in the liver.
 The excretion of clarithromycin occurs in bile,
feces and urine.

96. Cont’d…
Erythromycin
 The enteric coated tablets of erythromycin is
readily absorbed from the GIT, widely distributed
to most body fluids and is excreted in the bile.
Azithromycin
 The absorption of azithromycin is increased by the
presence of food in the GIT, widely distributed in
the body tissues where the concentration is higher
than that in blood and is excreted via the bile as
metabolites.

97. Side effects
 Epigastric discomfort
 Nausea
 Vomiting
 Diarrhoea
 Skin rash
 Anorexia
 Flatulence
 Headache
 Chest pain
 Urticaria
Note: The side effects of
macrolides are less with newer
macrolides (azithromycin &
clarithromycin).

98. Contraindications
 Patients with known hypersensitivity to the
drugs.

99. Drug interaction
 Clarithromycin and erythromycin may elevate
sildenafil plasma concentration leading to
increased adverse effects.
 Consider using azithromycin in this case.
 Macrolides may elevate the blood levels of
phenytoin when given concurrently.
 Macrolides may increase the anticoagulant effect
of warfarin when given concurrently.

100. Cont’d…
 Clarithromycin when co-administered, with
zidovudine may result into either a decrease or
increase in the plasma levels of zidovudine.
 Macrolides may interact with carbamazepine
leading to its increased plasma concentration
and toxicity.

101. Quinolones
 The first member of the quinolones was nalidixic
acid.
 The newer drugs (Fluoroquinolones) are
derived from modification of the structure of
nalidixic acid by addition of fluorine molecule.
 The fluoroquinolones have an extended
spectrum and increased potency compared to
nalidixic acid.

102. Fluoroquinolones
 Have a broad spectrum of activity against gran –ve
and gram +ve bacteria.
 Fluoroquinolones display concentration dependent
activity against most susceptible bacteria.
 Old fluoroquinolones have poor activity against
Streptococcus pneumoniae.
 Newer Fluoroquinolones such as moxifloxacin,
levofloxacin have good activity against
Strep.pneumoniae and atypical bacteria like
mycoplasma pneumoniae and C.pneumoniae

103. Mode of action
 Quinolones are bactericidal in action.
 Quinolones enter the bacterial cell wall by
passive diffusion and inhibit the DNA gyrase
enzyme.
 This subsequently disrupts bacterial DNA
replication.

104. Pharmacokinetics
 All quinolones are well absorbed after oral
administration.
 Antacids and milk decrease the absorption of
quinolones, achieve good concentration in urine
and are eliminated in urine.
 Fluoroquinolones achieve high tissue
concentration in the kidney, prostate, genital tract,
gall bladder and lungs (third generation
Fluoroquinolones).

105. Classification of Quinolones
Comments
Examples
Generation
• Effective against gram negative
bacteria but not pseudomonas. Use
limited to UTI because of the minimal
serum levels achieved in other tissues.
• Nalidixic acid can easily develop
resistance
Nalidixic acid
First generation
• Have increased activity against gram –
ve bacteria including pseudomonas,
gram +ve and atypical pathogen
(Ofloxacin).
Note: Have poor activity against
streptococcus pneumoniae
Ciprofloxacin
Norfloxacin
Ofloxacin
Pefloxacin
Lomefloxacin
Second
generation

106. Cont’d…
Third generation Levofloxacin,
sparfloxacin
Gatifloxacin
Moxifloxacin
• Spectrum of activity is the
same as the second
generation but with
expanded spectrum
against gram positives
including streptococcus
pneumoniae and atypical
pathogen

107. Route of administration
Drug Dosage form Route of administration
Ciprofloxacin Tablets 500mg, 1g
Injection 200mg/100ml
Eye drop 0.3% W/V
Oral
Injection
Topical eye drop
Norfloxacin Tablets 400mg Oral
Ofloxacin Tablets 200mg
Injection 200mg/100ml
Oral
IV infusion
Levofloxacin Tablets 250mg, 500mg
Injection 500mg/100ml
Oral
IV infusion
Moxifloxacin Tablets 400mg Oral

108. Spectrum of activity
 E.coli
 Proteus mirabilis
 K.pneumoniae
 Pseudomonas sp
 Salmonella sp
 Shigella
 Brucella sp
 M.catarrhalis
 H.influenzae
 Staph.aureus
 Mycobacteria
 Strep.pneumoniae

109. Clinical uses
Indications
Drug
Urinary tract infection
Shigellosis
Nalidixic Acid
Urinary tract infections
Septicaemia
Typhoid
Chancroid
Traveler’s diarrhoea
Shigellosis
Otitis media
Peritonitis
Osteomyelitis
Brucellosis
Respiratory tract infections
Chronic bacterial prostatitis
Ciprofloxacin

110. Cont’d…
Norfloxacin Gonorrhoea
Urinary tract infections
Chronic prostatitis
Ofloxacin Gonorrhoea
Urinary tract infections
Typhoid
Chronic prostatitis
PID
Infected diabetic foot
Skin and soft tissue infections

111. Cont’d…
Levofloxacin Hospital acquired pneumonia
Acute sinusitis
Chronic prostatitis
Urinary tract infections
Skin and soft tissue infections
Exacerbation of chronic bronchitis
Sparfloxacin Pneumonia
Urinary tract infection
Acute bronchitis
Non gonococcal urethritis
Uncomplicated gonorrhoea
Skin and soft tissue infections

112. Side effects
Gastrointestin
al
Nausea and vomiting, dyspepsia, flatulence,
diarrhoea, oral candidiasis
CNS Headache, insomnia, dizziness
Endocrine Hypoglycaemia or hyperglycaemia
Skin Skin rash, urticaria
Others Cartilage damage in growing bone,

113. Contraindications
 Children under 12years
 Pregnant mothers
 Breast-feeding mothers
 History of hypersensitivity to quinolones

114. Drug interaction
 Antacids reduce the absorption of quinolones.
 Cimetidine may interfere with elimination of
fluroquinolones leading to increased toxicity.
 Iron salts and zinc decrease the absorption of
quinolones.

115. Tetracyclines
 Tetracyclines have a broad spectrum of activity
against gram +ve, gram –ve bacteria and
atypical bacteria.
 They also have activity against protozoa
parasites
 The use of tetracyclines has declined because
of development of resistance.
 Most of the tetracyclines available in Uganda
are administered orally and in topical form.

116. Tetracyclines – examples
 Tetracycline
 Doxycycline
 Minocycline
 Oxytetracycline

117. Clinical uses
• Brucellosis
• Syphilis
• Gonorrhoea in
combination with
cefixime
• Pelvic inflammatory
disease in combination
with other antibiotics.
• Shigellosis
• Trachoma
• Cholera
• Pharyngitis
• Sinusitis
• Malaria
• Bronchitis
• Acne vulgaris

118. Side effects
 Nausea
 Vomiting
 Photosensitivity
 Discoloration of the teeth
 Oral/vaginal candidiasis
 Diarrhoea

119. Contraindications
 Pregnant mothers
 Children below 12years
 Patients with known hypersensitivity to
tetracyclines

120. Drug interaction
 Milk, antacids and iron supplements decrease
tetracycline oral absorption.
 Oral contraceptives effectiveness may be
decreased with concurrent use of tetracyclines.
 Anticonvulsants such as carbamazepine,
phenytoin and phenobarbitone may induce the
metabolism of tetracyclines thus reducing its
effectiveness.

121. Moxifloxacin (Micromox®)
 Moxifloxacin is a third generation fluroquinolone.
 It is effective against gram –ve, gram +ve and
atypical bacteria.
 It is well absorbed when given orally even in the
presence of food.
 It is metabolized in the liver and excreted in
feces.
 Moxifloxacin is available in oral form of 400mg
tablets.

122. Spectrum of activity
 S.pneumoniae
 K.pneumoniae
 M.catarrharis
 S.aureus
 Bacterioides fragilis
 C.pneumoniae
 Clostridum
perfringens
 E.coli
 P.mirabilis
 M.pneumoniae
 H.influenzae

123. Clinical uses
 Acute bacterial exacerbation of chronic
bronchitis.
 Acute bacterial sinusitis
 Community acquired pneumonia
 Intra-abdominal infections
 Complicated skin and skin structure infections

124. Dosing recommendation
Acute bacterial
exacerbation of chronic
bronchitis.
400mg once daily 5 days
Acute bacterial sinusitis 400mg once daily 10 days
Community acquired
pneumonia
400mg once daily 7-14 days
Intra-abdominal
infections
400mg once daily 5-14 days
Complicated skin and
skin structure infections.
400mg once daily 7-21 days

125. Target competitors of Micromox®
 Levofloxacin
 Co-amoxiclav
 Azithromycin/clarithromycin

126. Levofloxacin-indications
Acute bacterial
exacerbation of
chronic bronchitis.
500mg once daily 5 days
Acute bacterial
sinusitis
500mg once daily 10-15 days
Community acquired
pneumonia
500mg once daily 7-14 days
Chronic bacterial
prostatitis
500mg once daily 28 days
Acute pyelonephritis 500mg once daily 5-10 days

127. Co-amoxiclav- indications
 Pneumonia
 Sinusitis
 Urinary tract infections
 Osteomyelitis
 Cellulitis/boils
 Otitis media
 Intra-abdominal sepsis
 Acute exacerbation of chronic bronchitis

128. Azithromycin-indications
 Pneumonia
 Sinusitis
 Bronchitis
 Otitis media
 PID
 Typhoid
 Skin and soft tissue infections
 Non gonococcol urethritis

129. Positioning features
 Patient compliance (frequency and duration of
treatment)
 Spectrum of activity
 Safety profile (pregnancy & breast feeding)
 Effectiveness (low level of resistance)
 Cost

130. Discussion for positioning
features!

131. Thank you