RATIONAL USE OF ANTIBIOTICS

Contents

1. GENERAL PRINCIPLES IN THE USE OF ANTIBIOTIC

Introduction
Monitoring efficacy
2. ANTIBIOTICS GUIDELINES 1996
2.1 Guidelines on antibiotic therapy

Table 1.    Respiratory Infections

Table 2.    Urinary Tract Infections
Table 3.    Skin and Soft Tissue Infections
Table 4.    Musculosketel Infections
Table 5.    Gastrointestinal Infections
Table 6.    Genitourinary Infections (Including Sexually Transmitted Diseases)
Table 7.    Central Nervous System Infections
Table 8.    Cardiovascular Infections
Table 9.    Bacteraemia And Septicaemia
Table 10.  Other Infections
Table 11.  Infections Associated With Pregnancy
Table 12.  Chemoprophylaxis For Selected Medical Condition

3. SURGICAL CHEMOPROPHYLAXIS
4. GUIDELINES FOR SURGICAL ANTIBIOTIC PROPHYLAXIS

 Gynaecologic Surgery
 General Surgery
 Vascular Surgery
 Cardiac Surgery
 Thoracic Surgery
 Orthopaedic Surgery
 ENT Surgery
 Neurosurgery
 Urological surgery
 Endoscopic procedures

5. ANTIBIOTIC DOSAGES FOR ADULTS

6. ANTIBIOTIC DOSAGES FOR NEONATES WITH SERIOUS INFECTIONS
7. ANTIBIOTIC DOSAGES OF ORAL ANTIBIOTICS FOR NEONATES
8. PARENTERAL ANTIBIOTIC DOSAGES FOR SERIOUS INFECTIONS IN
INFANTS AND CHILDREN
9. ANTIBIOTIC DOSAGES OF ORAL ANTIBIOTICS FOR INFANTS AND
CHILDREN
GENERAL PRINCIPLES IN THE USE OF ANTIBIOTICS

Introduction

Antibiotics are one of the most commonly prescribed drugs today. Rational use of
antibiotics is extremely important as injudicious use can adversely affect the patient,
cause emergence of antibiotic resistance and increase the cost of health care.
Prescribing an antibiotic comprises several phases:

i) perception of need - is an antibiotic necessary ? 

ii) choice of antibiotic - what is the most appropriate antibiotic ? 
iii) choice of regimen : what dose, route, frequency and duration are needed ? 
iv) monitoring efficacy : is the treatment effective ?

Is an antibiotic necessary?

Antibiotics are generally only useful for the treatment of bacterial infections. It is
important to remember that not all fevers are due to infections and not all infections
are caused by bacteria. The majority of infections seen in general practice are of viral
origin and antibiotics can neither treat viral infections nor prevent secondary
bacterial infections in these patients. Even where a bacterial aetiology is established,
an antibiotic may not be always necessary. Many bacterial infections resolve
spontaneously. Minor superficial skin infections may be more suitably treated with a
local antiseptic. Collections of pus should be drained surgically and if drainage is
adequate, antibiotics are often not required. 
  
Choice of an antibiotic 
The successful outcome of therapy would depend very much on the choice of the
antibacterial agent. In the process of selecting an antibiotic, three main factors need
to be considered; the aetiological agent, the patient and the antibiotic. 
  
The aetiological agent 
Determination of the aetiological agent depends on a combination of clinical acumen
and laboratory support. In many instances an antibiotic prescription has to be made
based on the clinical diagnosis (empirical therapy). Even where a bacteriology report
is available it is necessary to interpret the report. Bacterial isolates from culture
specimens may represent normal flora, colonisers or contaminants rather than true
pathogens. Sensitivity results when available are at best only a guide to treatment.
Laboratory reports should always be viewed in the light of clinical findings. 
  
The patient 
Several patient factors have to be considered in selecting an antibiotic. Age is an
important factor. The very young and the very old tend to be more prone to the
adverse effects of the antibiotics. Neonates have immature liver and renal functions
which affect their ability to metabolise or excrete antibiotics. Antibiotics and their
metabolites may adversely affect growing tissues and organs in children. Elderly
patients are more likely to suffer from nephrotoxicity and allergic reactions. Dosage
modifications would also have to be made in those patients with hepatic or renal
impairment. Antibiotics can also give rise to severe toxic reactions in patients with
certain genetic abnormalities eg sulphonamides in patients with glucose-6-phosphate
dehydrogenase deficiency. Antibiotics should as far as possible be avoided in
pregnancy and when it is necessary to use an antibiotic, betalactam antibiotics and
erythromycin are probably the safest. A history of allergy to antibiotics should always
be sought before administration. Routine intradermal test doses for penicillin allergy
is of little value and may even be dangerous. If in doubt avoid betalactams and use a
macrolide or tetracycline (in adults) instead. In serious infections like meningitis and
bacteraemic shock the immediate institution of the best available antibiotic for the
suspected pathogen(s) is imperative as delay in treatment will increase both
mortality and morbidity. In less serious situations such as otitis media where
spontaneous recovery is common, an antibiotic that covers for the predominant
organisms is adequate. 
  
The antibiotic 
The clinician should have adequate knowledge of the pharmacokinetic properties of
the antibiotic he uses. Antibiotics vary in their ability to be absorbed orally or to
cross the blood brain barrier and these factors will affect their routes of
administration. The ability of the antibiotic to achieve therapeutic concentrations at
the site of infection is another important consideration thus antibiotics used for
treating urinary infections should ideally be concentrated in urine. Some antibiotics
have very severe toxic effects and are best avoided in certain conditions. The doctor
should also be aware of drug-drug interactions since many antibiotics can interact
with other non-antibiotic drugs. Finally the cost of the antibiotic is also of major
concern. In calculating costs it is perhaps more reasonable to take into account the
total cost of treatment rather than just the actual cost of antibiotic per dose. The
route of administration, the necessity for monitoring antibiotic levels and the
patient's length of stay in hospital can affect the cost of treatment as well. The
patient's compliance to medication is an important factor for consideration in the
choice of antibiotics. 
  
Choice of regimen 
Parenteral or oral 
Whether the route of administration should be oral or parenteral would depend on
whether the patient is able to take oral treatment reliably. In cases of severe sepsis
where rigors, hyperthermia/hypothermia, tachycardia and hypotension are present,
intravenous therapy should be instituted. When in doubt it would be safer to
commence intravenous treatment and review the treatment daily. 
  
Duration of treatment 
Except for a few conditions, the optimum duration of antibiotic treatment is
unknown. Many antibiotics are often presribed for a duration of 5-7 days.
Nevertheless it is reasonable to discontinue therapy even after a shorter period if the
patient's symptoms have resolved. There are however certain infections where
prolonged treatment is necessary (Table I). In some conditions eg uncomplicated
cystitis in women and gonococcal urethritis in males, single dose regimens have been
shown to be effective.
Table I. Conditions where a minimum duration of treatment has been
established.

Infection Minimum duration of treatment

Tuberculosis 4 -6 months

Empyema and lung abscess 4 - 6 weeks

Endocarditis 4 weeks

Osteomyelitis 4 weeks

Atypical pneumonia 2 - 3 weeks

Pneumococcal meningitis 7 days

Pneumococcal pneumonia 5 days

Monitoring efficacy 
Early review of response 
A routine early review ( 3 days after commencing treatment) of the patient's
response is important in order to ensure that the patient is receiving appropriate
treatment. After review the doctor will have to decide whether to:

i) continue with the present regimen 

ii) increase the level of treatment by changing from oral to parenteral; increasing the
dose or changingto a broader spectrum antibiotic 
iii) decrease the level of treatment by changing from parenteral to oral, decreasing
the dose or changing to a more specific narrow spectrum antibiotic 
iv) stopping the antibiotic if the infection has resolved; the objective of treatment is
achieved or the diagnosis has been changed. 
  
Inconsistent microbiology reports 
If the patient is responding there is no necessity to change antibiotic even when the
laboratory reports a resistant organism. The isolate in question could have been a
coloniser or a contaminant. Infections may resolve spontaneously and the antibiotic
could have affected the bacteria in a way that makes it more susceptible to the
host's immune defenses.

If the patient's condition fails to improve, a change in antibiotic may be necessary

even when the laboratory reports a sensitive organism. 
  
Causes of non-response to antibiotics 
A patient may fail to respond to an antibiotic for a number of reasons which include:

i) the aetiological agent is resistant to the antibiotic 

ii) the diagnosis is incorrect 
iii) the choice of antibiotic is correct but the dose and/or route of administration is
wrong 
iv) the antibiotic cannot reach the site of infection 
v) there is a colletion of pus that should be drained surgically or a foreign
body/devitalised 
    tissue that should be removed 
vi) there is secondary infection 
vii) antibiotic fever 
viii) non-compliance of the host 
  
Changing from intravenous to oral 
Wherever feasible intravenous therapy should be changed to oral therapy. The oral
antibiotic (not necessarily the oral preparation of the intravenous antibiotic) should
be selected based on clinical and laboratory findings. Similarly one should not
hesitate to revert to intravenous therapy if the patient's condition warrants it. 

ANTIBIOTIC GUIDELINES 1996

GUIDELINES ON ANTIBIOTIC THERAPY

The following guidelines are issued for the more common infections only. However
even for common infections they may not apply to certain patients. When in doubt
always seek a second opinion. The recommendations for first and second choice
regimens are based on a global assessment of efficacy, adverse effects , prevailing
sensitivity patterns and cost. It should also be noted that guidelines such as these
have to be reviewed and updated from time to time.

NOTE :

1. Erythromycin may be substituted for by a newer macrolide. 

2. Gentamicin may be substituted for by another aminoglycoside depending
on the local prevailing sensitivity pattern. 
3. Where ampicillin is recommended amoxycillin may also be used. 
    Ampicillin/amoxycillin may be substituted for by a betalactam/
betalactamase inhibitor combination depending on the local prevailing
sensitivity pattern. 
4. Cloxacillin is the drug of choice for severe methicillin
sensitive Staphylococcus aureus. For oral therapy flucloxacillin is preferred to
cloxacillin as the former is more reliably absorbed and achieves higher tissue
levels. In some children who cannot tolerate cloxacillin a first or second
generation cephalsoporin may be used. 
5. Quinolones are not recommended in children.
Abbreviations:

1o : First generation 
2o : Second generation 
3o : Third generation

Table 1.    RESPIRATORY INFECTIONS

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s
)

Acute Penicillin V Erythromyci The majority of sore

pharyngitis/tonsillit n throats are viral in origin
is, scarlet fever   and antibiotics are not
(Streptococcus indicated for treatment or
pyogenes suspected or prevention of secondary
proven) bacterial infections.

Diphtheria   Benzylpenicilli   Antibiotics are not the

(Corynebacterium n mainstay of treatment.
diphtheriae) Antitoxin and supportive
treatment are critical in
management.  
Close contacts should
receive erythromycin.
Non-immunised contacts
should be immunised.

Acute otitis media Ampicillin   New Most strains of Strep

and acute sinusitis   or   macrolides pneumoniae andHaemophi
(Strep pneumoniae, Betalactam/   lus influenzae in Malaysia
Haemophilus betalactamas are sensitive to ampicillin.
influenzae & Moraxella e inhibitor However many strains
catarrhalis) combination ofMoraxella catarrhalisare
resistant to ampicillin.

Acute epiglottitis   Chloramphe- Ampicillin Acute epiglottitis is a

(Haemophilus nicol or   medical emergency and
influenzae) 3o cephalo- hospitalisation with
sporin  aggressive therapy is
required

Pertussis   Erythromycin   Antibiotic treatment does

(Bordetella pertussis) not significantly alter the
course of disease. If given
early it helps to eradicate
oropharyngeal organisms
thus interrupting
transmission.
  

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s)

Acute bronchitis   Ampicillin Erythromycin  Acute bronchitis is primarily a viral

( 2o bacterial infections due or   infection and antibiotics are not
toStreptococcus Doxycycline indicated. However 2o bacterial
pneumoniae &Hae-mophilus (adults only) infection may occur in severe cases. 
influenzae)
Erythromycin is preferred
ifMycoplasma is suspected on
epidemiological or other grounds.

Acute exacerbations of Ampicillin   Erythromycin   

chronic bronchitis   or   or  
(Streptococcus pneumoniae, Betalactam/   Doxycycline  
Hae-mophilus influenzae, betalacta-mase (adults only)
Moraxella catarrhalis) inhibitor
combination

Acute bronchial asthma Antibiotics are   There is no evidence that antibiotics

not indicated will significantly alter outcome.

Pneumonia   Benzylpenicillin     Erythromycin is preferred

Community acquired or      when Mycoplasma is suspected.  
pneumonia - mild to Ampicillin        
moderate   or        
(Streptococcus pneumoniae, Erythromycin        
Hae-mophilus influenzae,         
Mycoplasma)          
        
Community acquired         
pneumonia - severe        
(Streptococcus pneumoniae,
Hae-mophilus influenzae, Benzylpenicillin Betalactam/   When Staph aureus is suspected or
Staphylococcus aureus, and   betalacta- demonstrated use cloxacillin and
Klebsiella pneumoniae) Gentamicin   mase inhibitor gentamicin.
or   combination
2o or 3o
Cephalo-sporin

Atypical pneumonia   Erythromycin    

(Mycoplasma pneu-moniae, or  
chlamydia,Legionella) Doxycycline (for
adults)

Chlamydia trachomatis Erythromycin   Transmitted from mother. Usually

penumonia in infancy becomes clinically apparent 2 - 20
weeks after birth.
 Condition 1st Choice 2nd Notes
antibiotic(s) Choice
antibiotic
(s)

Nosocomial pneumonia         

Post-operative/coma   Benzylpenicillin   
(aerobic gram negative bacilli, and  
streptococci, anaerobic mouth Gentamicin    
flora, Staphylococcus aureus) 
     
severe cases 
     
where MRSA is
demonstrated or strongly       
suspected  3o Cephalo-
sporin and    If vancomycin is not available a
ventilated patients   Gentamicin   combination of fucidin and rifampicin
(Pseudomonas aeruginosa, Vancomycin   may be used  
other aerobic gram negative     
bacilli)    
Gentamicin      
immunosuppressed  and      
(aerobic gram negative bacilli a 3o Cepha-   
andStaphylo-coccus aureus losporin    
 
   
Gentamicin    Pneumonia in the immunocompromised
and    may also be caused by a variety of non-
a 3o bacterial agents eg fungi (Candida,
Cephaloporin   Aspergillus ),Toxoplasma,
or    Pneumocystis and viruses.  
Ureido-penicillin
or     
Carbapenem
  

Lung abscess/        
empyema  
(mixed infection of Benzylpenicillin Empyema in childhood is nearly always
anaerobes,Staphylococcus and    due to staphylococci. Where
aureus, Streptococcus Gentamicin    staphylococci is suspected substitute
pneumoniae and aerobic and Metronida-zole cloxacillin for benzyl penicillin
gram negative bacilli)  
 Table 2.    URINARY TRACT INFECTIONS

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s)

Acute urinary tract infection   Cotrimoxa-zole    1o/2o cephalo- Many hospital acquired
(E. coli, Staphylococcus or   sporin pathogens are now
saprophyticus) Trimethoprim   resistant to ampicillin.  
or   In uncomplicated cystitis in
Ampicillin    adults 4 tabs
or   cotrimoxazole in a single
Nitrofurantoin  dose has been shown to be
effective. 
In pregnancy ampicillin
should be given for 10
days

Pyelonephritis and 2o Cephalo-sporin      In all cases an attempt

complicated urinary tract and    should be made to exclude
infection   Gentamicin   any underlying
(E. coli, or   abnormality
otherEnterobacteriaceae) a quinolone

Recurrent urinary infection   Cotrimoxazole  Ampicillin   Recurrent urinary tract

(E. 1 tab nightly   500 mg nightly   infections may require
coli, otherEnterobacteriaceae, or   or   very prolonged
enterococci) Nitrofurantoin  Cephalexin   prophylaxis.  
50 mg nightly 250 mg nightly   Female patients should be
or   advised on perineal
Nalidixic acid  hygiene and micturition
500 mg nightly after intercourse.  
Treat current infection
before starting on
prophylaxis.  
Cotrimoxazole should be
avoided during the 3rd
trimester of pregnancy.

Catheter associated  Treat accord-ing to   Isolation of bacteria in

infections   culture & sensitivity urine culture per se is not
(Enterobacteriaceae, report an indication while
Pseudomonas and Enterococcus) catheter is in-situ.
Antibiotics will not
eradicate the bacteria and
may promote resistance
instead.  
Treatment is only
necessary is systemic
signs are present and
based on the most recent
culture. Catheter care is all
important. Bladder
 irrigation is generally not
useful and may introduce
infection.  
The catheter should be
removed as early as it is
possible.  
If the catheter is changed
in the presence of
bacteriuria, a single
prophylactic dose of
antibiotic should be given
30 minutes before the
procedure.

Acute urinary infection in      In all cases assessment of

children   renal function
(E. coli and    (cystograms, ultrasound of
otherEnterobacteriaceae)  kidneys, ureters and
    bladder) should be
Mild  Cotrimoxa-zole   performed.  
or   Prophylactic antibiotics for
   Ampicillin   children < 4 years is
or   recommended in cases
Oral 1o cephalo- where anatomical
  
sporin  abnormalities are
detected.
   
   2o/3o cephalosporin 
Severe or  
aminoglycoside

 
 Table 3.    SKIN AND SOFT TISSUE INFECTIONS

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s)

Impetigo   Penicillin Erythromycin  Mupirocin ointment may be

(Strep pyogenes, Staph aureus) or   considered for topical use in
Cloxacillin and cases of MRSA infections.
Penicillin 
or  
Cephalexin

Boils and carbuncles   Erythromycin Cloxacillin   Surgical drainage is the definitive

(Staph aureus) or   mode of treatment and
Cephalexin antibiotics may not be necessary
if drainage is adequate.

Cellulitis/Erysipelas/  Benzylpenicillin         
Lymphangitis   or  
(Strep pyogenes)   Procaine     Change to oral therapy once
Severe cases  penicillin   patient's condition improves.  
  If staphylococci suspected or
   proven use a combination of
Penicillin V   penicillin and cloxacillin
Mild to moderate cases  or  
Erythromycin  
      
Facial and orbital cellulitis in  
children (Haem influenzae)
2o or 3o Ceph-
alosporin 

Decubitus ulcers   Antibioticsarenot   2o Cephalosporin and

(Enterobacteriaceae, Pseudomonas, indicatedunless Metronidazole may be used in
Enterococcus,anaerobic bacteria) systemic cases with systemic symptoms
symptoms are
present.

Diabetic foot infections   2o or 3o Cloxacillin    Diabetic foot infections may

(Polymicrobial infection Cephalo-sporin   and    involve extensive tissue and
- Enterobacteriaceae, Staph and Metronida- Gentamicin    bone necrosis. 
aureus,streptococci, anaerobic zole   and  
bacteria) or   Metronida- Surgical debridement is often
Betalactam- zole necessary. 
betalacta-mase
inhibitor The duration of treatment
combination depends on the response. 

Infected bites   Ampicillin   Erythromycin Tetanus toxoid should be

(animal bites :Pastuerella and/or    administered to patients
multocida,staphylococci  Cloxacillin requiring a booster. 
human bites : mouth flora) The value of antibiotic
prophylaxis in
clinically uninfectedbites is not
proven. For hand wounds and
extensive injuries a 5 day course
of antibiotics is advised. 

Human bites may have

medicolegal implications and
proper documentation including
photographs may be necessary.

Umbilical sepsis     Antibiotics are generally not

indicated.  
Where there is evidence of
spread a course of cloxacillin is
recommended.

Lymphadenitis   Cloxacillin      
(Staph aureus, Strep pyogenes) or  
Erythromycin  
or  
1oCephalosporin 

Table 4.    MUSCULOSKELETAL INFECTIONS

 Condition 1st Choice 2nd Choice Notes
antibiotic(s) antibiotic(s)

Acute osteomyelitis   Cloxacillin Fusidic acid For children < 5 yr use a combination
(Staph aureus of cloxacillin and 2o/ 3o Ceph-
-commonest; others alosporin  
includeEnterobacteriaceae,
Pseudomonas)   
In children < 5 yr
staphylococci,
streptococci andHaem
influenzae

Chronic osteomyelitis   Cloxacillin  Fucidic acid   Where MRSA is suspected or proven,

(Staph aureus, and   fucidic acid and rifampicin should be
Enterobacteriaceae, Pseud Rifampicin   1st choice antibiotics. 
aeruginosa) or according to
culture report For cases due to Pseud aeruginosa, an
antipseudomonal fluroquinolone may
be considered.

Septic arthritis   Cloxacillin   For children < 5 yr use a combination

( > 5 years : Staph of cloxacillin and 2o/ 3o Ceph-
aureus; < 5 years :Staph alosporin  
aureus, Haem influenzae)
 

Compound fractures        The optimum duration of antibiotic

(Staph aureus,gram administration has not been
negative bacilli)     established. No differences have been
shown in 1,3 or 5 day courses. 
Grade I fractures  2o or 3o Ceph-
alosporin   Infection is more likely in Grade 3
     fractures with severe soft tissue and
vascular injuries. Routine cultures
Grade II fractures  2o or 3o Ceph- should be taken and the antibiotics
alosporin   changed if necessary. This especially so
and   for cases where surgery is delayed. 
  
Gentamicin  
2o or 3o ceph- Early surgical debridement and
  
alosporin   adequate fracture stabilisation within
and  6-8 hours of injury is the most
   important aspect of treatment.
Gentamicin  
Grade III fractures
and  
Metronidazole

Gas gangrene   Benzylpenicillin   Use 4 mega 6 hrly

(Clostridium sp)
 

Table 5.     GASTROINTESTINAL INFECTIONS

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s
)

Gingivitis   Penicillin V      

(Spirochaetal organisms, and  
streptococci and oral anaerobes) Metronida-
zole

Periodontal infections   Penicillin V Erythromyci  

(Streptococci and oral n
anaerobes)

Oral thrush   Syrup Azole (oral  

(Candida albicans and other Nystatin gel)
candida species)

Acute cholecystitis   2o or 3o Gentamicin    

(Enterobacteriaceae, Ceph- with or
Enterococcus andBacteroides) alosporin   without  
with or Metronidazol
without   e
Metronidazole

Acute cholangitis   Ampicillin    Gentamicin  

(Enterobacteriaceae, or  
Bacteroides) 2o or 3o
Ceph-
alosporin

Acute peritonitis   Penicillin and 3o Ceph-  

Primary (children)   gentamicin  alosporin 
(Strep pneumoniae,other
streptococci,      
staphylococci,Enterobacteriacea
e)         
Primary (adults with cirrhosis)   3o Cephalo-
(Enterobacteriaceae)  sporin  Gentamicin 

Secondary        
(polymicrobial infection due
toEnterobacteriaceae,
       
Enterococcus andBacteroides)
2o/3o Gentamicin  
cephalo- and  
sporin and Metronida-
methronida- zole
zole
Antibiotic associated colitis   Vancomycin    
(Clostridium difficile) (oral)  
or  
Metronidazole

Enteric fever   Chloramphe- Ampicillin   The majority of

(Salmonella typhi, Salmonella nicol   or   strains
paratyphi) or   Quinolone of Salmonella
Cotrimoxazol typhiisolated in
e  Malaysia are still
or   sensitive to
Ceftriaxone chloramphenicol. 
 
The newer
fluoroquinolones
have been
shown to be
effective for the
treatment of
carriers.

Acute uncomplicated No antibiotic   Oral rehydration

diarrhoeas   necessary salt solutions
(viruses, E. coli, Salmonella sp, (ORS) should be
Shigella sp, Campylobacter) given for
replacement
therapy.
Salmonella
sepsis is not
uncommon in
severely ill
infants and a 3o
cephalosporin is
indicated when
suspected.

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s)

Cholera   Doxycycline   Replacement of fluids and

( Vibrio for 4 days correction of electrolyte
choleraeO1, imbalances are the mainstay
O139) of treatment.  
Use syrup tetracycline in
 children.

Bacterial Cotrimoxazole   Shigella in Malaysia is often

dysentery   (Only in resistant to multiple
(Shigella, severe antibiotics. For such strains
Salmonella, dysentery) the use of a quinolone may be
enteroinvasive considered.
E. coli)

Amoebic Metronidazole Tinidazole  

dysentery  
(Entamoeba
histolytica)

Liver abscess   Ampicillin   2o or 3o  

Pyogenic    and   ceph-
(coliforms, Metronida-zole  alosporin  
staphylococci, and  
micro-aerophilic    Metronida-
streptococci)  zole  
     
Amoebic     
(Entamoeba  
Metronida-zole
histolytica)
Tinidazole

Table 6.    GENITOURINARY INFECTIONS

Note : For all sexually transmitted diseases every effort should be made for contact
tracing and treatment of the sexual partners.

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s)

Pelvic inflammatory       
disease  
(anaerobic bacteria,
streptococci,Entero-   
bacteriaceae,
chlamydia,Neisseria   
gonorrhoeae)  
Mild to moderate 
  

  
Doxycycline  
and  
   Gentamicin  
and  
Severe Metronida-zole 

Doxycycline  
and  
2o or 3o cephalo-
sporin  
and  
Metronida-zole

Vaginitis           
Candidal  
(Candida albicans, Candida Nystatin   Fluconazole     
tropicalis, otherCandida spp)  or   or Ketoconazole 
Clotrimazole  or Itraconazole     
     
Trichomonal        
(Trichomonas vaginalis)     
Metronida-zole      Metronidazole should be
Bacterial vaginosis   or Tinidazole  avoided during the first
(Gardnerella vaginalis,       trimester. 
Mobiluncus, Bacteroides sp)  
Metronida-zole      
or   Ampicillin With recurrent infections
Tinidazole consider treatment for the
sexual partner as well.

Gonorrhoea          
(Neisseria gonorrhoeae)  
Uncomplicated urethritis, rectal Spectino-mycin   For uncomplicated urethritis,
and pharyngeal gonorrhoea  or   rectal and pharyngeal
Ceftriaxone   gonorrhoea single dose
    or   treatment is sufficient. 
    Ciprofloxacin 
Pelvic inflammatory   
disease    
   
    Spectino-mycin   For other forms of
  or   gonorrhoea, three day
2o or 3o Cephalo-
Adult gonococcal sporin   courses are required. 
ophthalmia   
  
   Ceftriaxone  
or     
    Spectino-mycin
Gonococcal ophthalmia    
neonatorum  

In gonococcal ophthalmia
parenteral antibiotics should
be accompanied by hourly
conjunctival irrigation with
saline or antibiotic eyedrops.

Non-gonococcal urethritis   Doxycycline     Doxycycline or erythromycin

(Chlamydia tra-chomatis, or   should be given for at least
Ureaplasma urealyticum)  Erythromycin  seven days.  
With certain newer macrolides
  single dose regimens have been
shown to be effective.

Inclusion conjunctivitis Doxycycline     Duration of treatment should be

(adults)   or   fourteen days.
(Chlamydia tra-chomatis) Erythromycin

Syphilis        For patients allergic to

(Treponema pallidum)  penicillin 
  
Early    
Procaine penicillin (10
   days) or   Erythromycin or doxycycline
Benzathine penicillin for 30 days 
    ( 2 weekly doses) 
    
Procaine   
    penicillin (21 days)   
Late  or  
benzathine penicillin    
   (3 weekly doses)   Erythromycin or doxycycline
  for 30 days 
   
    Procaine or Benzyl    
Neurosyphilis  pencillin (21 days)   

   Benzyl-penicillin Doxycycline for 30 days 

       
Congenital syphilis   
  Asymptomatic babies born of
syphilitic mothers should
also be treated

Chancroid   Cotrimoxazole or     Bubos should be aspirated, not

(Haemophilus ducreyi) Ceftriaxone incised and drained.

Table 7.    CENTRAL NERVOUS SYSTEM INFECTIONS

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s)

Meningitis (Haemophilus      When the pathogen is known

influen-zae, Streptococcus the antibiotic of choice for
pneumoniae, Neisseria pneumococcal and
meningitidis)     meningococcal meningitis is
benzyle penicillin. For
Adult     haemophilus meningitis
chloramphenicol or a 3o
   cephalosporin is the drug of
   
choice. 
Benzyl penici-llin and
   Chlor-amphenicol  
or   Meningitis caused by penicillin
3o Cephalo-sporin  resistant pneumococci and
   
ampicillin/chloram-phenicol
   
resistant haemophilus are still
Children  Ampicillin and  
uncommon in Malaysia. 
Chloramphe-nicol  
   or  
3o cephalo-sporin  Many laboratories have rapid
diagnostic kits and results can
    often be obtained within a few
Neonatal meningitis Ampicillin and
hours. 
gentamicin  
or  
3o cephalo-sporin  

Cryptococcal meningitis    Amphotericin B and 5   Fluconazole may be considered

(Cryptococcus neoform-ans) Flu-cytosine as an alternative drug for
cryptococcal meningitis.

Brain abscess (adults)   Benzylpenicillin  3o Cephalo- Surgical drainange is the

( Streptococci, anaerobic and   sporin   definitive treatment for brain
organisms)  Metronidazole   and   abscess.
  Metronidazole
Brain abscess (children)  
(Staphylococci, streptococci, Cloxacillin  
gram negative aerobic bacilli and  
and anaerobic organisms) 3o cephalo-sporin  
and  
Metronidazole

Table 8.    CARDIOVASCULAR INFECTIONS

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s)

Endocarditis   Benzylpenicillin     Dosage:  

Non-intravenous drug and   Penicillin 2-3 mega iv, 4-6 hrly for 4-6
user   Gentamicin  weeks  
(Streptococcus viridans Gentamicin 1.0 mg/kg iv, 8 hrly for 2-6
group)     weeks  
Cloxacillin 2 g iv, 4hrly for 6 weeks.  
Intravenous drug user   Cloxacillin    After 4 weeks of iv penicillin,
(Staphylococcus aureus)  and   replacement with oral penicillin plus
Gentamicin  probenecid can be considered.  
   When endocarditis is shown to be due
toEnterococcus use ampicillin 2 g iv
  
6hrly and gentamicin for 6 weeks.  
  
Endocarditis in IDUs often involves the
   tricuspid valves and associated with
Post-surgical pneumonia/lung abscess.  
endocarditis      Endocarditis in IDUs may occasionally
( Staphylococci, be caused by gram negative bacilli in
diphtheroids) Cloxacillin   which case treatment should be based
and   on the sensitivity report.  
Gentamicin For MRSA infections use vancomycin or
a combination of fucidic acid and
rifampicin.  
Staphylococcus epidermidis is often
resistant to cloxacillin thus vancomycin
may have to be used instead.  
Other bacteria and fungi can also cause
post-surgical endocarditis and treatment
will be according to culture report.  
Surgical intervention is often necessary
for prosthetic valve infection.

Table 9.    BACTERAEMIA AND SEPTICAEMIA

Condition(According to most likely 1st Choice 2nd Choice Notes

focus antibiotic(s) antibiotic(s)

Urinary (community acquired Ampicillin      

-Enterobact-eriaceae, Enterococcus)  and   
Gentamicin  
Urinary (hospital acquired  
-Pseudomonas and other gram
negative aerobic bacilli) 2o or 3o generation
Cephalo-sporin  
and  
Gentamicin

Gall bladder/bowel   3ogeneration Cephalo- Gentamicin    

(Enterobacteriaceae, sporin   and  
Enterococcus,anaerobic organisms) and   Metronida-zole  
Metronida-zole or  
Betalactam-
betalactamse
inhibitor
combination and
gentamicin

Female pelvis   Gentamicin   2o or 3o  

(Enterobacteriaceae, and   generation
Enterococcus,anaerobic organisms) Metronida-zole Cephalo-sporin  
and  
Metronida-zole

Skin (cellulitis)   Benzylpenicillin      

(Streptococcus pyogenes)    
    
Skin (abscess)  
(Staphylococcus aureus)  Cloxacillin    

Decubitus ulcers, diabetic foot      

ulcers  
(Aerobic gram negative bacilli, Cloxacillin     
anaerobic bacteria, staphylococci) and  
Gentamicin     
and  
Metronidazole
  Betalactam-
betalactamse
inhibitor
combination
and gentamicin

 
Intravascular lines  Cloxacillin   The infected line
(Staphylococci,Enterobacteriaceae) and   should be
Gentamicin removed.  
Where MRSA
and MRSE are
prevalent use
vancomycin or a
 combination of
fucidic acid and
rifampicin.

Lung - community acquired   Cloxacillin       

(Staphylococcus aureus)   and  
    Gentamicin    
Lung - hospital acquired  
(Staphylococcus aureus, aerobic gram        
negative bacilli) Cloxacillin     
and  
Gentamicin   3o generation
and   Cephalo-sporin  
Metronida-zole and  
Gentamicin and
Metronida-zole

Condition(According to most likely 1st Choice 2nd Choice Notes

focus antibiotic(s) antibiotic(s)

Neutropaenic 3o generation Ureidopeni-cillin   In a significant

Cephalosporin and   or   proportion of
Gentamicin carbapenem   neutropaenic
and   patients cultures
Gentamicin  are negative.  
Many authorities
   would
recommend
  commencement
of antifungal
treatment if
there is no
response after 3
- 5 days of
antibacterial
treatment.

Table 10.    OTHER INFECTIONS

Condition 1st Choice antibiotic(s) 2nd Choice Notes

antibiotic(s)

Scrub typhus   Tetracycline (to be given   If treatment is initiated before the

(Rickettsia until at least 48 hours after fifth day of clinical disease, a further
tsutsugamushi) fever has subsided)   3 day course 4 days later is required
 or   to prevent relapse.
Doxycycline for 3 days

Melioidosis   Ceftazidime for 14-21   Treatment for longer than 3 months

(Burkholderia days   may be necessary for some cases
pseudomallei) followed by  
Doxycycline  
or  
Cotrimoxazole  
or Amoxycillin/clav-ulanic
acid for 3 months

Table 11.    INFECTIONS ASSOCIATED WITH PREGNANCY 

Antibiotics should be used with care in pregnancy. Beta-lactam antibiotics and
macrolides are probably the safest antibiotics to use in pregnancy.

Condition 1st Choice 2nd Choice antibiotic(s)

antibiotic(s)
Asymptomatic bacteriuria/ Ampicillin    
Cystitis   or  
( E. coli ) Cephalexin

Acute pyelonephritis   2o or 3o generation Ampicillin

( E. coli ) Cephalo-sporin

Condition 1st Choice 2nd Choice antibiotic(s)

antibiotic(s)

Chorioamnionitis/  2o or 3o generation Ampicillin  and  Gentamicin  and  

Prolonged rupture of Cephalosporin  Metronidazole
membranes   and  
(Group B streptococci, Metronidazole
anaerobes,Enterobacteriaceae)

Puerperial and post-abortal 2o or 3o generation Ampicillin  and  Gentamicin  and  

sepsis   Cephalosporin  Metronidazole
(Streptococci,Entero-coccus, and  
staphylococci,Enterobacteriaceae, Metronidazole
anaerobes)

 Table12.    CHEMOPROPHYLAXIS FOR SELECTED MEDICAL CONDITIONS

Condition 1st Choice 2nd Choice Notes

antibiotic(s) antibiotic(s)

Rheumatic fever Benzathine Penicillin V    Prophylaxis should be maintained for

penicillin 1.2 mega 250 mg 12 many years. Children should continue to
every 4 weeks hrly   receive prophylaxis until the age of 25
or   years and adults for at least 5 years
Erythromycin  whichever is the longer.
250 mg 12
hrly

Cholera Tetracycline      
1 g daily for 5
days  
or  
Doxycycline 200
mg stat dose

Condition 1st Choice antibiotic(s) Notes

Bacterial Amoxycillin 3 g oral 1 hour Patients allergic to penicillin  

endocarditis   before procedure   Erythromycin 1.5 g orally 1 hour before
For dental and upper or   procedure folowed by 500 mg 6 hours later  
respiratory Ampicillin 1 g iv just before or  
procedures  pro-cedure followed by 500 mg Vancomycin 1 g iv just before procedure 
6 hrs later 
     
Ampicillin 1 g iv just before
   procedure followed by 500 mg Dosages for children:  
6 hrs later and   Amoxycillin 50mg/Kg before and 25 mg/Kg
For patients who have Gentamicin 1.5 mg/kg iv just after  
prosthetic valves or before procedure and I dose 6 Gentamicin 2 mg/Kg before  
previous endocarditis hr later   Cloxacillin 50 mg/Kg before  
undergoing dental    
and upper respiratory
procedures; and for Cloxacillin 1 g iv and   Clindamycin is preferred in patients on long
patients undergoing Gentamicin 1.5 mg/kg iv  term penicillin
genitourinary just before procedure
manipulation 

For patients with

prosthetic valves
undergoing cardiac
catheterisation, pace-
maker insertion and
skin biopsy

Post splectomised Penicillin V 250 mg 12 hrly   Pneumococcal vaccine should be given to the
children or   patient one month before splenectomy
Benzathine penicillin 1.2 mega
monthly

Close contacts of Adults (menin-gococcal only)  In meningococcal meningitis treatment of

meningococcal and the patient with penicillin may not reliably
haemophilus Rifampicin 600 mg 12 hrly for clear the nasopharynx of meningococci. A
meningitis   2 days  prophylactic course of rifampicin is advised
patients for the convalescent patient before discharge
Children ( Men-ingococcal and back to the family circle.
haemophilus) 

Rifampicin   
10 mg/kg/day   
12 hrly for 4 days

SURGICAL CHEMOPROPHYLAXIS 
The use of antibiotic prophylaxis has been shown to prevent post-surgical wound
infections. When employed rationally significant reductions in morbidity and mortality
and savings in resources can be achieved. However when used excessively and in
situations when its benefit has not been proven, perioperative antibiotics can lead to
unjustifiably high costs of medical care. Single dose regimens or very short courses
are unlikely to lead to emergence of bacterial resistance but routine prolonged
courses have been clearly associated with increased rates of resistance.

Surgical operations can be divided into four broad categories :

 clean (eg breast, thyroid and hernia operations)

 clean contaminated (eg upper gastrointestinal and biliary)
 contaminated (eg colorectal and trauma surgery within 4 hours of injury)
 dirty (eg perforated intestinal viscus, trauma surgery after 4 hours of injury)

Prophylaxis is generally recommended for clean-contaminated and contaminated

operations. In clean operations prophylaxis maybe justified if the consequence of
infection is very serious eg in cardiac operations and orthopaedic implants.

Another factor which should be considered in determining probability of infection is

the patient himself. Factors that reduce host defenses eg old age, malignancy,
malnutrition, steroid therapy, etc will increase the risk of infection. 
  
 In using antibiotics for surgical chemoprophylaxis the following principles should be
adhered to:

1. It is important to distinguish between prophylaxis and treatment.

Prophylaxis is given 
    when no infection exists previously. When an infection is already present,
even when 
    clinically not evident, treatment should be given. 
2. Prophylaxis should be given only in certain conditions where the benefits
clearly 
    outweigh the risks. The cost of prophylaxis should also be considered. 
3. The antibiotic should be directed at the most likely contaminating organism
for that 
    particular procedure. Choice of antibiotic will also depend on whether the
patient 
    has been in hospital for a prolonged period and the current pattern of
antibiotic 
    resistance in the hospital. In general the agent selected should (a) be of
low toxicity (b) have an 
    established safety record (c) reach a useful concentration in the relevant
tissues. 
4. The route of administration, timing and duration of giving the antibiotic is
planned to 
    achieve the maximum concentration of the antibiotic in the tissues during
and shortly 
    after the operation. Antibiotics are preferably given by the intravenous
route at the 
    time of induction of anaesthesia. In most instances a single pre-operative
dose would 
    suffice. Where surgery is prolonged additional intraoperative doses may be
given. 
    There is no evidence that there is any benefit in extending prophylaxis
beyond 24 
     hours after the operation. 
5. Topical antibiotics are not recommended with the exception of opthalmic
surgery 
    and cases of extensive skin loss. 
6. Surgical chemoprophylactic regimens should be reviewed regularly and
changes 
    made if necessary. 
 

GUIDELINES FOR SURGICAL ANTIBIOTIC PROPHYLAXIS

Gynaecologic surgery

Operative procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)

Caesarean section   2o or 3o cephalosporin 1. Gentamicin and

(anaerobes, streptococci, Metronidazole  
aerobic gram-negative 2. Ampicillin and
bacilli) Metronidazole

Hysterectomy   2o or 3o cephalosporin Ampicillin and

(anaerobes, streptococci) Metronidazole

  

General Surgery

Operative 1st Choice 2nd Choice

procedure antibiotic (s) antibiotic(s)
Cholecystectomy (open 2o or 3o cephalosporin 1. Beta-lactam/beta-
and laparoscopic)   lactamase inhibitor  
(Aerobic gram-negative 2. Gentamicin
bacilli, enterococci,
anaerobes)

Oesophageal/gastric 2o or 3o cephalosporin Beta-

surgery   lactam/betalactamase
(Aerobic gram-negative inhibitor
bacilli, streptococci)

Colorectal surgery   2o or 3o cephalosporin   Gentamicin and

(Anaerobes, aerobic and   Metronidazole
gram-negative bacilli, Metronidazole
enterococci)

Appendicectomy   2o or 3o cephalosporin   Gentamicin and

(Anaerobes, aerobic and   Metronidazole
gram-negative bacilli, Metronidazole
enterococci)

Vascular Surgery

Operative procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)

Arterial replacement/ by- 2o cephalosporin Cloxacillin and Gentamicin

pass surgery

Cardiac Surgery

Operative Procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)

Valve replacement and 2o or 3o cephalosporin  

coronary grafts

  

Thoracic Surgery

Operative Procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)
Lobectomy and 2o or 3o cephalosporin  
pneumonectomy

  
Orthopaedic Surgery

Operative Procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)

Arthroplasty and joint Cloxacillin and Gentamicin 2o cephalosporin

replacements  
(Staphylococci)

Open reduction of Cloxacillin and Gentamicin 2o cephalosporin

fractures  
(Staphylococci)

ENT Surgery

Operative Procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)

Major oral, head and neck 2o or 3o cephalosporin    

surgery   and  
(streptococci, anaerobes, Metronidazole
aerobic gram-negative
bacilli)

Neurosurgery

Operative Procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)

Craniotomy   2o cephalosporin Cloxacillin and Gentamicin

(Staphylococci)

Shunt procedures   2o cephalosporin Cloxacillin and Gentamicin

(Staphylococci)

Urological surgery

Operative Procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)
Stone surgery and 2o or 3o cephalosporin Gentamicin
prostatectomy  
(Enterobacteriaceae)

    
Endoscopic procedures 
Antibiotic prophylaxis for endoscopic procedures are given for 2 main reasons: 
1) to prevent endocarditis (see table below for degree of risk) 
2) to prevent infective complications 
 

Operative Procedure 1st Choice antibiotic(s) 2nd Choice

antibiotic(s)

Hepatobiliary, 2o or 3o cephalosporin Gentamicin

pancreaticin the presence
of obstruction  
(Enterobacteriaceae)

Cystoscopy, nephroscopy 2o or 3o cephalosporin Gentamicin

and stents  
(Enterobacteriaceae)

Arthroscopy   2o cephalosporin Cloxacillin and Gentamicin

(Staphylococci)

Estimated risk of endocarditis associated with preexisting cardiac disorders. 

(From New Engl J Med 1995, 323:39) 
  
 

Relatively high risk Intermediate risk Very low or negligible

risk

Prosthetic heart valves    Mitral valve prolapse with Mitral valve prolapse
Previous endocarditis   regurgitation   without regurgitation  
Cyanotic congenital heart Pure mitral stenosis   Trivial valvular
failure   Tricuspid valve disease   regurgitation on
Patent ductus arteriosus  Pulmonary stenosis   echocardiography without
Aortic regurgitation   Asymmetric septal structural abnormality  
Aortic stenosis   hypertrophy   Isolated atrial septal
Mitral regurgitation   Bicuspid aortic valve or defect  
Mitral stenosis and calcific aortic sclerosis Arteriosclerotic plaques  
regurgitation   with minimal Coronary artery disease  
Ventricular septal defect  haemodynamic Cardiac pacemaker  
Coartation of the aorta   abnormality   Surgically repaired
Surgically repaired Degenerative valvular intraccardiac lesions, with
intracardiac lesions with disease in elderly minimal or no
residual haemodynamic patients   haemodynamic
abnormality Surgically repaired abnormality, more than
intracardiac lesions with six months after operation
no haemodynamic
abnormality, less than 6
months after the
operation

    

ANTIBIOTIC DOSAGES FOR ADULTS

Note : The following dosing guidelines are the usually recommended regimens. They
may not apply to all patients nor to all infections. When in doubt always consult a
specialist.
 Antibiotic Usual oral regimen Usual parenteral regimen

Amphotericin B   0.25 - 1.5 mg/kg/day

Amikacin   7.5 mg/kg 8 hrly

Amoxycillin 250 - 500 mg 8 hrly  

Amoxycillin-Clavulanate  250 - 500 mg 8 hrly (based on  

amoxycillin)

Ampicillin 250 - 500 mg 6hrly 1 - 2 g 6 hrly

Ampicillin-sulbactam 375 - 750 mg 12hrly 1 - 2 g 6hrly or 8 hrly

(Sultamicillin) 

Azithromycin 500 mg dly  

Bacampicillin 400 - 800 mg 12 hrly  

Carbenicillin 500 mg - 1 g 6 hrly 5 - 6 g 6 hrly

Cefoperazone   1 - 2 g 8 - 12 hrly

Cefotaxime   1 - 2 g 8 - 12 hrly

Ceftazidime   1 - 2 g 8 - 12 hrly

Ceftriaxone   500 mg - 1 g 12 - 24 hrly

Cefuroxime 250 mg 12 hrly 750 mg - 1.5 g 8 - 12 hrly

Cephalexin 250 mg - 1 g 6 hrly  

Chloramphenicol 250 - 750 mg 6 hrly 250 mg - 1 g 6 hrly

Ciprofloxacin 250 - 750 mg 12 hrly 400 mg 12 hrly

Clarithromycin 250 - 500 mg 12 hrly  

Clindamycin  150 - 300 mg 6 hrly 300 - 900 mg 6 - 8 hrly

Cloxacillin  500 mg - 1 g 6 hrly 1 - 2 g 6 hrly

Doxycycline 100 mg 12 hrly  

Erythromycin 250 - 500 mg 6 hrly 1 g 6 hrly

Fluconazole 100 - 200 mg per day 100 - 200 mg per day

Flucytosine 37.5 mg/kg 6 hrly  

Fusidic acid 500 mg 8 hrly 500 mg 8 hrly

Gentamicin   1.5 - 2 mg/kg 8 hrly

Imipenem/Cilastatin   500 mg - 1 g 6hrly

Itraconazole 100 - 200 mg per day  

Kanamycin   5 - 7.5 mg/kg 8 hrly

Ketoconazole 200 - 400 mg 12 - 24 hrly  

Metronidazole 250 - 750 mg 8 hrly 500 mg 8 hrly

Nalidixic acid 1 g 6hrly  

Netilmicin   1.5 - 2 mg/kg 8 hrly

Nitrofurantoin 50 mg - 100 mg 6 - 8 hrly  

Norfloxacin 400 mg 12 hrly  

Nystatin 0.5 - 1 million units 6 hrly  

Ofloxacin 200 - 400 mg 12 hrly  

Pefloxacin 200 - 400 mg 12 hrly  

Penicillin G   1 - 4 mega 4 - 6 hrly

(Benzylpeniciilin)

Procaine penicillin   0.6 - 1.2 mega 12 - 24 hrly

Benzathine penicillin   0.6 - 1.2 mega monthly

Penicillin V 250 - 500 mg 6 hrly  

Piperacillin   3 - 4 gm 4 - 6 hrly

Rifampicin 600 mg 24 hrly 600 mg 24 hrly

Tetracycline 250 - 500 mg 6 hrly  

Tobramycin   1.5 - 2 mg/kg 8hrly

Trimethoprim- 800 mg (based on  

sulphamethoxazole sulphamethoxazole) or 2 tabs
(Cotrimoxazole) 12 hrly

Vancomycin   250 - 500 mg 8 - 12 hrly

Aminoglycoside dosing : There is now evidence to show that once daily dosing is as
effective as multiple dosing. 
 

ANTIBIOTIC DOSAGES FOR NEONATES WITH SERIOUS INFECTIONS 

Note : The following dosing guidelines are for intravenous administration.

Antibiotic Full term neonate Premature neonate

Amikacin <7 days : 20mg/kg div. 15 mg/kg div. 12 hrly

12 hrly  
>7 days : 30 mg/kg div.
12 hrly

Ampicillin <7 days : 150 mg/kg div. 100 mg/kg div. 12 hrly
8hrly  
>7 days : 200 mg/kg div.
6 hrly

Cefotaxime <7 days : 100 mg/kg div. 100 mg/kg div. 12 hrly
12 hrly  
>7 days : 150 mg/kg div.
8hrly

Ceftazidime <7 days : 100 mg/kg div. 100 mg/kg div. 12 hrly
12 hrly  
>7 days : 150 mg/kg div.
8 hrly

Ceftriaxone <15 days : 20-50 mg/kg <15 days : 20-50 mg/kg once daily  
once daily   >15 days : 20-80 mg/kg once daily
>15 days : 20-80 mg/kg
once daily

Chloramphenicol <2 weeks : 25 mg/kg div. 25 mg/kg div. 8hrly

8 hrly  
>2 weeks : 50 mg/kg div.
8 hrly

Clindamycin  20 mg/kg div. 8 hrly 15 mg/kg div. 8 hrly

Cloxacillin  <10 days : 200 mg/kg <10 days (<2.5 kg) : 100 mg/kg div.
div. 8 hrly   8hrly; >10 days (<2.5 kg) : 100
>10 days : 200 mg/kg mg/kg div. 8 hrly
div. 6 hrly
Gentamicin <7 days : 5 mg/kg div. 5 mg/kg div. 8 hrly
12 hrly  
>7 days : 7.5 mg/kg div.
8 hrly

Imipenem <7 days : 40 mg/kg div. 40 mg/kg div. 12 hrly

12 hrly  
>7 days : 60 mg/kg div.
8 hrly

Kanamycin <7 days : 20 mg/kg div. <3 days : 10 mg/kg once daily  
12 hrly   >3 days : 20 mg/kg div. 12 hrly
>7 days : 30 mg/kg div.
8 hrly

Metronidazole 15 mg/kg loading dose,  

then 15 mg/kg div 12 hrly

Netilmicin <7 days : 5 mg/kg div. 5 mg/kg div. 8 hrly

12 hrly  
>7 days : 7.5 mg/kg div.
8 hrly

Penicillin G <7 days : 250,000 U/kg 250,000 U/kg div. 12 hrly

(Benzylpeniciilin) div. 8 hrly  
>7 days : 400,000 U/kg
div. 6 hrly

Tobramycin <7 days : 5 mg/kg div. 5 mg/kg div. 8 hrly

12 hrly  
>7 days : 7.5 mg/kg div.
8 hrly

Vancomycin <7 days : 30 mg/kg div. 30 mg/kg div. 12 hrly

12 hrly  
>7 days : 45 mg/kg div.
8 hrly

ANTIBIOTIC DOSAGES OF ORAL ANTIBIOTICS FOR NEONATES

Antibiotic Daily dosage

Amoxycillin 20-40 mg/kg div. 8 hrly

Ampicillin 50-100 mg/kg div 8 hrly

Cephalexin 50 mg/kg div 6 hrly

Chloramphenicol < 14 days : 25 mg/kg div 8 hrly  
> 14 days : 50 mg/kg div. 6 hrly

Clindamycin  20 mg/kg div. 6 hrly

Cloxacillin  > 2.5 kg : 50-100 mg/kg div. 6 hrly  

< 2.5 kg : 50 mg/kg div. 8 hrly

Erythromycin < 7 days : 20 mg/kg div. 12 hrly  

> 7 days : 20-40 mg/kg div. 6 hrly

Metronidazole 25 mg/kg div. 12 hrly

Penicillin V 50,000 U/kg div. 8 hrly

  

PARENTERAL ANTIBIOTIC DOSAGES FOR SERIOUS INFECTIONS IN INFANTS

AND CHILDREN

Antibiotic Daily dosage

Aminoglycosides   22 mg/kg div. 8 hrly  

Amikacin    7.5 mg/kg div. 8 hrly  
Gentamicin    30 mg/kg div. 8 hrly  
Kanamycin    7.5 mg/kg div. 8 hrly  
Netilmicin    20 mg/kg div. 12 hrly  
Streptomycin    5 mg/kg div. 8 hrly
Tobramycin

Cephalosporins   > 12 years : 150 mg/kg div. 8 hrly  

Cefoperazone    200 mg/kg div. 6 hrly  
Cefotaxime    150 mg/kg div. 8 hrly  
Ceftazidime    100 mg/kg once daily
Ceftriaxone

Chloramphenicol 100 mg/kg div. 6 hrly

Clindamycin  40 mg/kg div. 6 hrly

Erythromycin 40 mg/kg div. 6 hrly

Imipenem 40-60 mg/kg div. 6 hrly

Metronidazole 30 mg/kg div 6 hrly

Penicillins   400,000 U/kg div. 6 hrly  

Penicillin G    50,000 U/kg single dose im.  
Benzathine penicillin    50,000 U/kg div. 12 hrly im.  
Procaine penicillin    200 mg/kg div. 6 hrly  
Ampicillin    200 mg/kg div. 6 hrly  
Cloxacillin    200 - 300 mg/kg div. 6 hrly
Piperacillin

Rifampicin 10 - 20 mg/kg div. 12 hrly

Trimethoprim- 20 mg TMP/100 mg SMX/kg div. 6 hrly

sulphamethoxazole
(Cotrimoxazole)

Vancomycin 40 mg/kg div. 6 hrly

ANTIBIOTIC DOSAGES OF ORAL ANTIBIOTICS FOR INFANTS AND CHILDREN

Antibiotic Daily dosage

Azithromycin 10 mg/kg dly

Cephalosporins   30 mg/kg div 12 hrly  

Cefuroxime    25 - 50 mg/kg div. 6 hrly  
Cephalexin    20 - 50 mg/kg div 8 hrly  
Cefaclor    30 mg/kg div 12 hrly  
Cefadroxil    25 - 50 mg/kg div 12 hrly
Cephradine

Chloramphenicol 50-100 mg/kg div. 6 hrly

Clindamycin  25 mg/kg div. 6 hrly

Macrolides   15 mg/kg div. 12 hrly  

Clarithromycin    25 - 50 mg/kg div. 6 hrly
Erythromycin

Metronidazole 25 mg/kg div 6 hrly

Nalidixic acid 50 mg/kg div 6 hrly

Nitrofurantoin 7 mg/kg div 6 hrly  

2 mg/kg single dose dly (prophylaxis)

Penicillins   <10kg : 125 mg 8 hrly; >10 kg : 250 mg 8

Penicillin V    hrly 
Amoxycillin    20 - 40 mg/kg div. 8 hrly  
Ampicillin    50 - 100 mg/kg div. 6 hrly  
Cloxacillin    50 - 100 mg/kg div. 6 hrly  
Amoxycillin-clavulate    20 - 40 mg/kg div. 8 hrly  
Sultamicillin 25 - 50 mk/kg div 12 hrly
Rifampicin 20 mg/kg div. 12 hrly

Trimethoprim- 6-20 mg TMP/30-100 mg SMX/kg div. 12 hrly

sulphamethoxazole
(Cotrimoxazole)