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1. Guidelines for rational use of
antibiotics in surgical
prophylaxis
DR. M. LAKSHMI GAYATHRI, PHARM D
ASSISTANT PROFESSOR

2. Introduction:
 Introduction: 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.
 Need of antibiotics: antibiotics are genrally only useful for the treatment of
bacterial infectios
 Majority of the infectionsseen in general practice which are of viral origin and
in that casse antibiotics can neither treat such as a viralinfcetions nor to prevent
secondary bacterial infections in those patients

3.  Selection of antibiotics: 3 main factors are needed to be considered in the process of
selection of antibiotics.
1. based on patient
2. based on etiological agent
3. based on pharmacokinetic properties
Based on patient: several factors have to be considered in selecting an antibiotic to patient.
1. Age: very young and very old tend to be more prone to adverse effects of antibiotics
Neonates have immature liver and renal functions which affect their ability to
metabolise or excrete antibiotics
Elder patients suffer from nephrotoxicity and allergic reactions

4.  Pregnancy: antibiotics should be avoided in pregnancy and if it is necessary to use
an antibiotics , then βlactam antibiotics and erythromycin are probablythe most
safest.
 Infections: in serious infections like meningitis and incase of bacteremic shock, the
immediate institution of best available antibiotics is more preferable for the
suspected pathogen. With delayed treatment it will increase the both morbidity and
mortality.
 In less serious situation like otitis media where a spontaneous recovery is most
commonly required then a general antibiotics are adequate.

5.  Patients with hepatic or renal impairment : In case of antibiotic use in these elderly
patients with renal or hepatic impairment the dose modification should be followed.
2. Based on etiological agent: determination of etiological agent( infectious agent) which
is depends on a combination of clinical aspect as well a laboratory values. Even though the
bacteriological report is available , it indicates that best antibiotics are used for the
treatment.

6.  3. based on pharmacokinetic properties: generally physicians should have the
adequate knowledge of pharmacokinetic properties of antibiotics
 Factors affecting these properties:
>Route of administration: antibiotics vary in their ability to be absorbed
orally or to cross BBB and some of these factors will affect their route of
administration.
>Therapeutic concentration: the ability of antibiotics to achieve the
therapeutic concentrations at the site of infections is an another important
consideration…like when antibiotics used for UTI they should ideally be
concentrated in the urine.

7.  Physicians should also be aware of some drug drug interactions since
many antibiotics can interact with other non antibiotic drugs in a condition
where a minimum duration of treatment has been established.
 infections minimum duration of treatment
tuberculosis 4-6 months
endocarditis 4 weeks
pneumonia 5 days

8.  Antibiotics for surgical prophylaxis: they are used to prevent infections at the
surgical site.
 Prophylaxis is become standard for contaminated and clean contaminated surgery
and also for surgery involved in the insertion of artificial devices
 A single dose of antibiotics is usually sufficient, if the duration of the surgery is
four hours or even less and it should be given at correct time prior to surgery before
one hr or 30 min.
 Inappropriate use of antibiotics for surgical prophylaxis increases both cost and also
favour the emergence of resistance bacteria.

9.  Principles of surgical antibiotic prophylaxis: first decide if prophylaxis is
appropriate.
 choose the less expensive drug if two are of with equal antibacterial spectrum,
efficacy, toxicity, and ease of administration.
 Administer dose at right time and also for short period of time
 Avoid antibiotics which are used in the treatment of serious sepsis
 Do not use antibiotic prophylaxis to overcome poor surgical technique
 Review the protocols of prophylactic antibiotics regularly as both cost and hospital
antibiotic resistance patterns may change

10.  Indications for antibiotics in surgical prophylaxis: a classification system which ranks procedures
according to their potential risk for infectious complications has facilitated the procedures for the
study of antibiotic surgical prophylaxis.
 clean
 clean- contaminated
 contaminated
 The most widely accepted indications fro the antibiotics prophylaxis are contaminated and clean
contaminated surgery and operations involving the insertion of an artificial device.
 Less accepted for clean operations in pts with impaired host defences or for neurosurgery, heart
surgery or any ophthalmic surgeries.

12.  Choice of antibiotics: choice 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), cephalosporins are
also contraindicated, as there is a small but significant risk of cross reaction.
 Always select an antibiotics with narrowest antibacterial spectrum , to reduce the
emergence of multi resistance pathogens
 If the pt develops sever sepsis then broad spectrum antibiotics should be selected.

13.  The use of third generation cephalosporins such as ceftriaxone and cefotaxime
should 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 should be choosen as
antibiotics for surgical prophylaxis comprise a large portion of hospital pharmacy
budgets
 Commonly used surgical prophylaxis are IV first generation cephalosporins-
cephazolin or cephalothin
 IV gentamicin

14.  IV or Rectal metronidazole if anerobic infection is likely present
 Oral tinidazole
 IV flucloxacillin if methicillin suscepitible staphylococcal infection is
likely
 IV vancomycin in case of methicillin resistant staphylococcal infection

16.  Route and frequency of antibiotic administration:
 Oral and rectal antibiotics need to be given earlier to ensure adequate tissue
concentration during surgery
 Metronidazole suppositories are commonly use in bowel surgery and must be
given 2-4 hrs before surgery
 Generally topical antibiotics are not recommended with exceptions of ophthalmic
and burns surgeries

17.  Prophylactic antibiotics are usually given IV as a bolus on induction of
anesthesia t ensure adequate tissue concentration at the time of surgical incision
 IM antibiotics are less used than IV .they are typically given at the time of pre
medications so that peak tissue levels are attained at most critical time.