This document provides guidelines for the rational use of antibiotics and surgical prophylaxis. It defines rational drug use and discusses the importance of promoting it. Guidelines are presented for rational prescribing and use of antibiotics. Key points include using antibiotics only when necessary, obtaining cultures before treatment when possible, choosing appropriate agents, doses and durations. Guidelines for surgical prophylaxis emphasize using antibiotics only for specific procedures shown to reduce infections and administering the appropriate agent at induction of anesthesia for most surgeries under 4 hours. Causes of non-responsiveness to antibiotics are also summarized.

1. GUIDELINES FOR RATIONAL USE OF
ANTIBIOTICS AND SURGICAL
PROPHYLAXIS
M. Immanuel Jebastine,
M. Pharm, (Hon.D)Hum., (Ph.D).,
Assistant Professor,
VISTAS

2. RATIONAL DRUG USE
GUIDELINES
RATIONAL USE OF ANTIBIOTICS
SURGICAL PROHYLAXIS

3. RATIONAL DRUG USE
• DEFNITION
 RDU may be defined as the use of an
appropriate,efficacious,safe and cost effective dug given
for the right indication in the right dose and
formulation,at right interves and for right duration of
time.
 The promotion of rational drug use involves a wide
range of activities such as the adoption of the essential
drug concept, training of health professionals in rational
drug use and the development of evidence based
clinical guidelines. unbiased and independent drug
information, continuing education of health
professionals, consumer education and regulatory
strategies are also vital to promote rational drug use.

4. IMPORTANCE OF RATIONAL DRUG USE
The importance of rational drug use relates to its
imapact on the health of the individuals and
communities, healthcare costs and environment.
irrational drug use leads to ineffective and unsafe
drug treatment, worsening or prolonging of
illness, and adverse drug reaction. inappropriate
treatment also increase the cost to the patient,
government or insurance system. widespread
antibiotic resistance is partially due to irrational
use of antibiotics.

5. GUIDELINES FOR RATIONAL DRUG USE
Good prescribing requires a sound and up –to
–date knowledge of pharmacology and
applied therapeutics.However,even this is not
enough unless a systematic approach to
prescribing is adopted.The following general
guidelines for good prescribing should be used
in every clinical situation where during
therapy may be indicated:

6. • Define the patients problem then specify the therapeutic
objective for this problem in this particular patient.
• Decide whether a drug is needed to achieve a therapeutic
objective.Use drugs only when indicated,and when the
potential benefits of drug therapy outweigh the potential
risks.
• Choose a drug of proven efficacy and safety.The drug must
also be suitable for the individual patient,and be
affordable.
• Choose a dose which is suitable for the individual patient.
• Avoid using more than one drug of the same chemical class
at the same time.

7. • Inform the patient how to take the medication,how long it
will take to work,how long to continue with treatment and
possible side effects,and what to do if these occur.
• Monitor the effects of treatment.
• If treatment has not been effective try and identify why.
• Decide whether the drug should be continued at the
present dose,at a different dose or stopped.

9. RATIONAL USE OF ANTIBIOTICS
• Infectious diseases are a major cause of morbidity and
mortality in developing countries. Almost one third of
drug used is antibiotics. Antibiotics are widely misused
for conditions where they are not needed, such as
treatment of common cold and other upper respiratory
infections of viral origin. Starting antibiotics without a
diagnosis frequently changing antibiotics,giving
suboptimal doses,not completing the course of
treatment and relying on antibiotics without draining
pus or removing foreign bodies as indicted,are wasteful
practices and can lead to antibiotic resistance.The
following are the guidelines that ensure the rational
use of antibiotics:

10. • Use antibiotics only when indicated
• Where appropriate ,specimens for gram stain,culture
and sensitivity testing should be obtained before
commencing antibiotic therapy.
• When an antibiotic is indicated ,the choice of agent
should be based on factors such as spectrum of activity
in relation to the known or suspected causative
oraganism,safety,previous clinical response,cost,ease
of use and the potential for selection of resistan
organisms.
• An adequate dose and duration of treatment is
essential for all antibiotic therapy.

11. • A history of allergy or other adverse effect to the drug
under consideration should always be sought.
• Prophylactic use of antibiotics should be restricted to
situation where it has been shown to be effective or
where the consequences of infection are disastrous.
• Empirical antibiotic therapy should be based ,where
possible on local epidemiological data on potential
pathogens and their patterns of sensitivity.
• Antibiotic therapy directed at specific organisms should
include the most effective,least toxic and narrowest
spectrum agent available.

12. • Oral therapy should be used in preference to
parenteral therapy whenever clinically possible.
• Antimicrobial combinations should only be used
where indicated:
To extend the spectrum of cover in mixed
infections
To achieve a synergistic bactericidal effect.
To prevent the emergence of resistant organisms.
(Eg: In the therapy of TB)

13. • Topical antibiotics should be restricted to few
proven indications.(Eg : Eye infections)
• Reserve new antibiotics for situation where
serious infection have not or are unlikely to
respond to conventional agents.

14. ANTIBIOTICS FOR SURGICAL
PROPHYLAXIS
DEFNITION:- Surgical antibiotic prophylaxis is
defined as the use of antibiotics to prevent
infections at the surgical site. Prophylaxis has
become the standard of care for contaminated
and clean-contaminated surgery and for
surgery involving insertion of artificial devices.
The antibiotic selected should only cover the
likely pathogens, It should be given at the
correct time.

15. • For most parenteral antibiotics this is usually
on induction of anaesthesia. A single dose of
antibiotic is usually sufficient if the duration of
surgery is four hours or less. Inappropriate use
of antibiotics for surgical prophylaxis increases
both cost and the selective pressure favouring
the emergence of resistant bacteria.Wound
infections are the commonest hospital-
acquired infections in surgical patients.

16. • They result in increased antibiotic usage,
increased costs and prolonged hospitalisation.
• Appropriate antibiotic prophylaxis can reduce
the risk of postoperative wound infections,
but additional antibiotic use also increases the
selective pressure favouring the emergence of
antimicrobial resistance. Judicious use of
antibiotics in the hospital environment is
therefore essential.

17. Approximately 30-50% of antibiotic use in
hospital practice is now for surgical
prophylaxis. However, between 30% and 90%
of this prophylaxis is inappropriate. Most
commonly, the antibiotic is either given at the
wrong time or continued for too long.
Controversy remains as to duration of
prophylaxis and also as to which specific
surgical procedures should receive
prophylaxis.

18. PRINCIPLES OF ANTIBIOTIC
PROPHYLAXIS
• Decide if prophylaxis is appropriately.
• Determine the bacterial flora most likely to cause
postoperative infection (not every species needs
to be covered)
• Choose an antibiotic, based on the steps above,
with the narrowest antibacterial spectrum
required
• Choose the less expensive drug if two drugs are
otherwise of equal antibacterial spectrum,
efficacy, toxicity, and ease of administration
• Administer dose at the right time

19. • Administer antibiotics for a short period (one
dose if surgery of four hours duration or less)
• Avoid antibiotics likely to be of use in the
treatment of serious sepsis
• Do not use antibiotic prophylaxis to overcome
poor surgical technique
• Review antibiotic prophylaxis protocols
regularly as both cost and hospital antibiotic
resistance patterns may change.

20. CHOICE OF ANTIBIOTICS
 The choice of the antibiotic for prophylaxis is based on
several factors. Always ask the patient about a prior
history of antibiotic allergy, as beta-lactams are the
commonest type of antibiotics used in prophylaxis. A
history of severe penicillin allergy (anaphylaxis,
angioedema) means that cephalosporins are also
contraindicated, as there is a small but significant risk of
cross-reaction.Most importantly, the antibiotic should
be active against the bacteria most likely to cause an
infection . Most postoperative infections are due to the
patient's own bacterial flora. Prophylaxis does not need
to cover all bacterial species found in the patient's flora,
as some species are either not particularly pathogenic
or are low in numbers or both.

21. • It is important to select an antibiotic with the
narrowest antibacterial spectrum required, to
reduce the emergence of multi-resistant
pathogens and also because broad spectrum
antibiotics may be required later if the patient
develops serious sepsis. The use of 'third
generation' cephalosporins such as ceftriaxone
and cefotaxime should therefore be avoided in
surgical prophylaxis. Often several antibiotics are
equal in terms of antibacterial spectrum, efficacy,
toxicity, and ease of administration. If so, the least
expensive drug should be chosen, as antibiotics
for surgical prophylaxis comprise a large portion
of hospital pharmacy budgets.

22. Commonly used surgical prophylactic antibiotics
include:
• intravenous 'first generation' cephalosporins -
cephazolin or cephalothin
• intravenous gentamicin
• intravenous or rectal metronidazole (if anaerobic
infection is likely)
• oral tinidazole (if anaerobic infection is likely)
• intravenous flucloxacillin (if methicillin-susceptible
staphylococcal infection is likely)
• intravenous vancomycin (if methicillin-resistant
staphylococcal infection is likely).

23. Parenteral 'second generation' cephalosporins
such as cefotetan have improved anaerobic and
aerobic Gram-negative cover compared to first
generation cephalosporins. They are sometimes
used as a more convenient, but more expensive,
alternative to the combination of metronidazole
plus either first generation cephalosporin or
gentamicin for abdominal surgical prophylaxis.The
bacterial flora in some hospitalised patients may
include multi-resistant bacteria such as
methicillin-resistant staphylococci. An assessment
then needs to be made for each surgical
procedure about whether or not prophylaxis with
parenteral vancomycin is indicated.

24. ROUTE AND TIMING OF ANTIBIOTIC
ADMINISTRATION
 It is critical to ask the patient about beta-lactam allergy
prior to anaesthesia to minimise the risk of anaphylaxis
under anaesthesia. A test dose of antibiotic is not
necessary before surgery if the patient denies
antibiotic allergy.Prophylactic antibiotics are usually
given intravenously as a bolus on induction of
anaesthesia to ensure adequate tissue concentrations
at the time of surgical incision. This timing of dosing is
particularly important for most beta-lactams which
have relatively short half-lives. Vancomycin has to be
infused over one hour so it must be started earlier so
the infusion finishes just before induction.

25. Intramuscular antibiotics are less commonly
used than intravenous antibiotics. They are
typically given at the time of pre-medication so
that peak tissue levels are attained at the most
critical time, the time of surgical incision. Oral
or rectal antibiotics need to be given earlier to
ensure adequate tissue concentrations during
surgery. Metronidazole suppositories are
commonly used in bowel surgery and must be
given 2-4 hours before it begins. Topical
antibiotics are not recommended, with the
exceptions of ophthalmic or burns surgery.

26. USE OF ANTIBIOTICS IN SURGICAL
PATIENTS
Bacterial contamination of a surgical wound is
more likely to arise from the patient’s own
flora; however, the surgeon and the surgical
environment (including instruments) are also
possible sources. Many of the rituals of
surgical preparation are directed at reducing
the potential for bacterial contamination of
the open wound. Such rituals include:

27. 1. Preparation of the patient by clipping fur around
the surgical site and using antiseptic washes to
remove oil, organic debris and to reduce the
numbers of transient and resident bacteria.
2. The use of dedicated surgical attire for the
surgeon (including scrubs, hats, mask), and
similar decontamination of the surgeon’s hands
using antiseptic washes and surgical gloves.

28. 3. Sterilisation of instruments.
4. Utilising drapes and other barriers to isolate
the surgical wound from the unprepared areas
of the animal and surgical table.

29. • In human surgery, such routines are universally
accepted as a minimum standard of care in the
operating theatre. However, there is good
evidence that the veterinary profession in the UK
has a low level of implementation of such
accepted practices. In a recent survey of first-
opinion practices, sterile surgical gloves were
utilised in just 37.5% of practices, with gowns,
masks and facemasks being worn in just 14.3%,
12.5% and 10.7% of practices, respectively.In a
separate study, practices were evaluated on their
use of different skin preparation techniques.

30. • This study found that 79% of practices were
unaware of the concentration of scrub
preparation being used, or the contact time
necessary between the antiseptic and skin during
surgical preparation. In some cases, the
concentration of antiseptic being used may
actually have been too low to be effective at
killing bacteria. Twelve percent of practices used
chlorhexidine gluconate and povidone–iodine
together to prepare the skin; however, these two
agents are incompatible and the combination
effectively provides limited or no skin asepsis.

31. CAUSES OF NON-RESPONSIVENESS 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

32. REFERENCE
• TEXTBOOK FOR CLINICAL PHARMACY BY
G .PARTHASARATHI
MILAP. C. NAHATA
• TEXTBOOK OF PHARMACOTHERAPEUTICS BY
ROGER WALKER