Introduction to Prophylaxis and Empirical uses of Antibiotics

1. .
Haroon RASHID
Doctor of pharmacist
Rehman medical institute

2. Anti microbial agents
An antimicrobial is an agent that
kills microorganisms or inhibits their growth.
Antibiotic = a chemical that is produced by one
microorganism and has the ability to harm other
microbes.
For example, antibacterial are used
against bacteria and anti-fungal are used
against fungi.

3. Classification of Antimicrobial
 Antibacterial …..
 Antifungal
 Antiviral
 Antiprotozoal
 Non-pharmaceutical………….
A wide range
of chemical and natural compounds are used
as antimicrobials. Organic acids are used
widely as antimicrobials in food products,
e.g. lactic acid, citric acid, acetic acid, and
their salts, either as ingredients, or as
disinfectants.

4. Antibiotic prophylaxis
 The use of antimicrobial medicines to prevent infection is
known as antimicrobial prophylaxis.
 Antibiotic prophylaxis refers to the prevention
of infection complications using antimicrobial therapy -
 Example
surgical procedures can introduce bacteria and
other microbes in the blood (causing bacteremia), which
can colonize and infect different parts of the body.
 Antibiotics can be effective in reducing the occurrence of
such infections. Patients should be selected for
prophylaxis if the medical condition or the surgical
procedure is associated with a considerable risk of
infection

5. Prophylactic antibiotics
 Prophylaxis with antibiotics has
decreased the high incidence of
wound infection after head and neck
operations that involve incisions
through oral or pharyngeal mucosa.
 Prophylactic administration of
antibiotics can decrease postoperative
morbidity, shorten hospitalization, and
reduce overall costs attributable to
infections.

6. Prophylactic antibiotics
 Many antibiotics require a single dose
given within 30 minutes of skin
incision to provide adequate tissue
concentration throughout the
operation.
 Additional doses during the procedure
are advisable if surgery is prolonged
(i. e, >4 h), major blood loss occurs, or
an antimicrobial with a short half-life is
used

7. Aims of antibiotics prophylaxis
 The aim of prophylaxis is to augment
host defense mechanisms at the time of
bacterial invasion,.
 Prophylaxis is an attempt to attack
organisms before they have a chance to
induce infection.
 Previous surgery (i. e, scarring) and
radiation injury decrease host defenses.
 Likewise, certain medical conditions,
such as diabetes mellitus or HIV,
predispose the patient to infection
because of diminished host response.

8. Choosing an antibiotic for
prophylaxis
Choosing an antibiotic for prophylaxis is
multi-factorial and should be based on
the following:
 Type of operation
 Kinetics and toxicity of the drugs
 Microbiologic characteristics of the
operative site
 Antibiotic sensitivities specific to the
particular hospital environment

9. Choosing an antibiotic for
prophylaxis
 The regimen chosen should be
compatible with findings from the
hospital's infection control wound
surveillance report. (warda)
 This regimen is particularly important
in hospitals with high incidence of
infection with methicillin-resistant
organisms (e.g., S aurous [MRSA], S
epidermidis [MRSE]) or with newly
Vancomycin-resistant organisms
(VRSA).

10. ADMINISTRATION OF
INTRAVENOUS
PROPHYLACTIC ANTIBIOTICS
Prophylaxis should be started preoperatively in
most circumstances
ideally within 30 minutes of the induction of
anesthesia.
Antibiotic prophylaxis should be administered
immediately before or during a procedure.
Prophylactic antibiotics should be administered
intravenously.
The single dose of antibiotic for prophylactic
use is, in most circumstances, the same as
would be used therapeutically.

11. .
An additional dose of prophylactic agent
is not indicated in adults, unless there
is blood loss of up to 1500 ml during
surgery-

12. Duration of Preoperative
Antibiotic Use
 1. Prophylactic preoperative antibiotics
should be started prior to skin incision for
maximal benefit.
 2. There is no advantage to continuation of
preoperative antibiotics beyond 24 to 48
hours postoperatively has ever been
demonstrated.
 Other indications: young women with
recurrent • urinary tract infection, prophylaxis
against type A influenza with
amantadine,lifelong prophylaxis of individuals
who have had severe Endocarditus.

13. Exception
The possible exception to this is
metronidazole;
 because metronidazole may enter
abscess spaces better than other
antibiotics.
 its prolonged use has been associated
with less severe postoperative
infections in one study.

14. Disadvantages
 It promotes antibiotic resistance and
contributes to super infection.
 Antibiotic use is also costly and
associated with allergic reactions,
toxic reactions, and adverse effects

15. Empherical therapy
 A medical treatment not derived from
scientific method but derived from
practical experience or observations,
survey or common use.
 Relay on or derived from observation
or experiment (empirical result that
support the hypothesis)
 In the medical term we can say that
when a treatment is started before a
diagnosis is conformed.

16. Empiric therapy
 Empiric therapy prior to completion of
lab tests: • it may be necessary to
begin treatment in patients with
serious infections BEFORE the lab
results.
Take samples for culture PRIOR TO
INITIATION of treatment.

17. Empherical therapy
 Empherical therapy mostly based on
experience.
 It should be begun on the basis of a
clinical educated guess in the absence
of complete or perfect information.
 Empherical therapy is most often used
when antibiotic are given to a person
before the specific bacterium causing
infection is known.

18. Empherical therapy
 For example choosing antibiotics
using clinical consideration
e g : the history and physical
examinations
Suppose you a middle ear infection
caused by a strain of hemophillus
influenza that is susceptible to sulpha-
and penicillin (rare)
Doctor after listening and examining
you and concluded that you have

19. Empherical therapy
 Rather than waiting 2-3 days to find
out what but this is and what it
respond to, and doctor may give you
amoxicillin because he know that they
are 99% effective in this clinical
setting.

20. .
THANKS