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introduction.ppt
1. Younas Masih
RN, Post RN BSc.N
(Lecturer )
New Life College Of Nursing Karachi
11/7/2014 1
Antimicrobial medications
2. Objectives
By the end the unit students will be able to:
1. Discuss and review common terms and concepts
related to antimicrobial therapy.
2.Discuss mechanism of action and indication of using
antimicrobial therapy.
3. State appropriate nursing implications for a client
receiving antimicrobial drugs.
4. Discuss general principles and consideration related
to antimicrobial therapy.
5. Calculate the drug dosage for oral and parental
antimicrobial drugs.
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Antimicrobial medications
3. Terms
Antimicrobial agent
It is a chemical substance derived from a biological
source or produced by chemical synthesis that kills or
inhibits the growth of microorganisms.
Before antimicrobials, large number of people died
from common illnesses
Now many illnesses easily treated with antimicrobials
However, many antimicrobial drugs are becoming less
useful.
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Antimicrobial medications
5. Antibiotics
Antibiotic
It is a chemical substance produced by a
microorganism that inhibits the growth of or kills other
microorganisms.
Or
A chemical substance derivable from a microorganism
or produced by chemical synthesis that kills or inhibits
microorganisms and cures infections.
1. Bacteriostatic: inhibit growth of microorganisms
2. Bactericidal: Kill microorganisms
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Antimicrobial medications
6. Sources of Antibacterial Agents
Natural - mainly fungal sources(The original
antibiotics were derived from fungal sources. These
can be referred to as “natural” antibiotics) e.g.
Benzylpenicillin and Gentamicin are natural
antibiotics
Semi-synthetic - chemically-altered natural
compound (developed to decrease toxicity and
increase effectiveness). E.g . Ampicillin and
Amikacin are semi-synthetic antibiotics
Synthetic - chemically designed in the
lab(bacteria are not exposed to the compounds
until they are released. They are also designed to
have even greater effectiveness and less toxicity).
E.g. Moxifloxacin and Norfloxacin are synthetic
antibiotics
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Antimicrobial medications
7. Mechanisms of action of
Antibacterial Drugs
1. Inhibit cell wall synthesis
2. Inhibit protein synthesis
3. Inhibit nucleic acid synthesis
4. Injury to plasma membrane
5. Inhibit synthesis of essential metabolites
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Antimicrobial medications
8. Mechanisms of Action
-Antibiotics operate by inhibiting crucial life
sustaining processes in the organism: the synthesis of
cell wall material the synthesis of DNA, RNA,
ribosomes and proteins.
Target
The target of the antibiotic should be selective to
minimize toxicity…but all antibiotics are toxic to some
degree!
Harm the bacteria, not the host
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Antimicrobial medications
10. Staining and Identification
Gram Staining
In this procedure bacteria are washed with a
decolorizing solution after being dyed with crystal
violet. On adding a counterstain such as safranin or
fuchsine after washing,
Gram-negative bacteria are stained red or pink
Gram-positive bacteria retain their crystal violet dye.
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Antimicrobial medications
12. Spectrum of Activity
Antimicrobial medications vary with respect to the
range of microorganisms they kill or inhibit
Narrow-spectrum antimicrobial (Some kill only
limited range) :
Broad-spectrum antimicrobial (While others kill
wide range of microorganisms)
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Antimicrobial medications
13. Adverse Effects
1. Allergic Reactions: some people develop
hypersensitivities to antimicrobials
2. Toxic Effects: some antimicrobials toxic at high
concentrations or cause adverse effects
3. Suppression of normal flora: when normal flora
killed, other pathogens may be able to grow to high
numbers
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Antimicrobial medications
14. Selection of the appropriate
antibiotic
It depends upon
knowledge of organism’s natural resistance
pharmacological properties of the antibiotic toxicity,
binding,
distribution, absorption achievable levels in blood,
urine
previous experience with same species
nature of patients underlying pathology
patient’s immune status
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Antimicrobial medications
15. Ideal Antibacterial
Selective target – target unique
Bactericidal – kills
Narrow spectrum – does not kill normal flora
High therapeutic index – ratio of toxic level to
therapeutic level
Few adverse reactions – toxicity, allergy
Various routes of administration – IV, IM, oral
Good absorption
Good distribution to site of infection
Emergence of resistance is slow
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Antimicrobial medications
16. Effects of Combining Drugs
1. Combinations are sometimes used to fight
infections
2. Synergistic: action of one drug enhances the
activity of another or vice versa.
3. Antagonistic: activity of one drug interferes with
the action of another.
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Antimicrobial medications