Antibiotics

Antibiotics nursingstudents.ning.com

Antibiotics
disrupts proteins or enzymes within a bacterium.
bacteriostatic – prevents multiplication
bactericidal – kills bacteria
Goal : to reduce the number of bacteria  immune system can deal with infection.

Culture & Sensitivity test
Identify the causative bacteria & the antibiotic which it is most sensitive

Gram- positive bacteria
cell wall retains stain or resist decolorization by alcohol
MC in respiratory & soft tissue infections
Gram – negative bacteria
cell wall loses stain or decolorized by alcohol
MC in GI & GU tract infections
Aerobic bacteria vs Anaerobic bacteria

Broad – spectrum Antibiotic
used for both gram – positive & gram negative bacteria
Narrow – spectrum antibiotics
used for either gram – positive or gram – negative bacteria
Synergistic effect  combination of antibiotics produce greater effects
ex. amoxicillin + clavulanic acid ( Augmentin)
ampicillin + sulbactam (Unasyn)
Prophylaxis  prevention of potential infection.

Antibiotic resistance
bacteria mutate that they become resistant to certain antibiotics.
common in nosocomial infections
cause: indiscriminate antibiotic use

Cross – resistance
resistance that occurs between antibacterials with similar actions.

General adverse reactions to antibacterials
allergy / hypersensitivity reactions
superinfections
organ toxicity

Classes
of
Antibiotics

Aminoglycosides

Drugs
gentamicin (Garamycin) M.C.
amikacin
neomycin
tobramycin
streptomycin
Kanamycin
“ M.C.” most common

Indications
Treatment of serious infections
Gm (-) infections {Kleb, enterobacter, E. coli. Proteus, Pseudomonas, Serratia- ( KEEPPS) }
Methicillin-resistant staph aureus (MRSA)

Action
inhibits protein synthesis of gram (–) negative bacteria (bactericidal)

Monitor for:
nausea & anorexia
ototoxicity
nephrotoxicity
neurotoxicity
BM depression & superinfections

Cephalosporins

Drug
cefaclor (Ceclor)

Indications
Treatment of respiratory
dermatological
urinary tract
middle ear infections

Action
inhibits cell wall synthesis of wide-range of bacteria (bactericidal )

Monitor for:
GI upsets & diarrhea
Pseudomembranous colitis
headache, dizziness
nephrotoxicity
superinfections & bone marrow suppression
hypersensitivity reactions

Generations
of
Cephalosporin

1st generation
Drugs
cephalexin (Keflex)
cefazolin (Zolicef)
Indication
same as gram – positive bacteria affected by Pen G & gram – negative bacteria ( Proteus mirabilis, E. coli, & Klebsiella pneumoniae) PEcK

2nd generation
Drugs
cefaclor
cefuroxime ( Zinacef)
Cefoxitin
Indications
same as 1 st gen plus Haemophilus influenzae, Enterobacter aerogenes &
Neisseria (HENPEcK)
Less effective against gram – positive bacteria

3rd generation
Drugs
ceftazidime
ceftriaxone (Rocephin)
Ceftizoxime
Indication
more potent against gram- negative bacilli as well as Serratia marcescens
(HENPEcKS)

4th generation
Drugs
cefepime
Ceftditoren
Indication
for gram – negative & gram – positive organisms including P. aeroginosa

Fluoroquinolones

Drugs
ciprofloxacin (Cipro) M.C.
levofloxacin
norfloxacin
ofloxacin
gatifloxacin

Indications
Treatment of :
respiratory infections
skin infections
urinary tract infections
eye infections
ear infections
bone & joint infections
Treatment after anthrax exposure
typhoid fever

Action
inhibit synthesis of bacterial RNA & DNA in wide spectrum of gram – negative bacteria

Monitor for:
headache, dizziness
GI upsets
BM depression  Contraindicated in children < 18 yo
risk of photosensitivity

Macrolides

Drugs
erythromycin M.C.
azithromycin (Zithromax)
clarithromycin

Indications
Treatment of respiratory, skin, urinary tract & GI infections
Good alternative if allergic to penicillins

Action
inhibit protein synthesis (bacteriostatic or bactericidal)

Monitor for:
nausea & vomiting
diarrhea
risk for pseudomonas colitis
hepatotoxicity
ototoxicty

Indications
similar to macrolides but more toxic. Treatment of serious infections.

Monitor for:
severe pseudomembranous colitis
BM depression
pain

Monobactam Antibiotic

Drug
aztreonam

Indications
Treatment of lower respiratory, skin, urinary tract, intra-abdomina & gynecological
infections caused by gram- negative bacteria including septicemia
Alternative to pxs allergic to penicillins or cephalosporins.

Action
inhibit cell wall synthesis of gram- negative enterobacteria

Monitor for:
mild GI problems
liver toxicity
pain

Penicillins & Penicillinase Resistant Antibiotics

Drugs
amoxicillin M.C.
Natural Penicillins
penicillin G
penicillin V
extended- spectrum penicillin
amoxicillin
ampicillin
penicillinase – resistant antibiotics
cloxacillin
nafcillin
oxacillin

Indications
Treatment for broad spectrum respiratory & urinary tract infections

Action
inhibit cell wall synthesis (bactericidal)

Monitor for:
GI effects
superinfections
hypersensitivity reactions

Sulfonamides

Drugs
sulfasalazine M.C.
sulfadiazine
cotrimoxazole

Indications
Treatment of rheumatoid arthritis, ulcerative colitis

Action
blocks cellular metabolism of PABA for folic acid synthesis of susceptible gram- positive & gram-negative baceria (bacteriostatic)

Monitor for:
hepatotoxicity
nephrotoxicity
Stevens- Johnson syndrome
CNS effects & BM depression

Tetracyclines

Drugs
tetracycline M.C.
doxyclcine
minocycline

Indications
Treatment of various infections, acne

Action
inhibit protein synthesis

Monitor for:
damage teeth & bones
GI effects
BM suppression, photosensitivity & superinfections
make oral contraceptives ineffective

Antituberculosis drugs

Drugs
1st line drugs
isoniazid (INH)
rifampin
ethionamide
rifapentine
2nd line drugs
ethambutol
pyrazinamide
3rd line drugs
capreomycin
cycloserine

Indication
Treatment & prophylaxis of tuberculosis

Monitor for:
discoloration of body fluids
hepatotoxicity
peripheral neuritis

Leprostatic drugs
dapsone
clofazimine
thalidomide

To Prevent Drug- resistant strains of bacteria!!!
use antibiotics cautiously
complete full course of therapy
avoid saving antibiotics for self-medication

END
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Antibiotics

by Junrill Galvez on May 15, 2008

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Antibiotics — Presentation Transcript