Transcript ANTIMICROBIAL THERAPY

Introduction to Antimicrobial Drugs
Classification by Susceptible
Organism
–Antibacterial
–Antiviral
–Antifungal
–Antiprotozoan
–Anthelmintic
Mechanism Of Action
Inhibition of bacterial cell wall
synthesis
Inhibition of protein synthesis
Inhibition of nucleic acid synthesis
Inhibition of metabolic pathways
Disruption of cell membrane
permeability
Inhibition of viral enzymes
Direct Exam Of Tissue &
Secretions
Gram stain
Morphology
Use of special reagents, stains
Cultures
Common organisms and
identification
Diagnosis Of Infection
Signs and symptoms
fever, increased WBC, pain,
inflammation, erythema
Microscopic exam of fluids
CSF, urine, blood
Identification of organism
culture, sensitivity
Empiric Therapy
The antibiotic selected is one
that can best kill the
microorganisms known to be
the most common cause of
infection
Empiric Therapy Selection
Patient Characteristics
age, immune function, other disease
states, pregnancy, renal/hepatic
function
Site of Infection
Drug Characteristics
efficacy, side effects, tissue
penetration, cost
Prophylactic Therapy
The antibiotic given when
there is likelihood of
microorganisms being
present and used to
PREVENT infection
Antimicrobial Resistance
Production Of Druginactivating Enzymes
Mrsa
Vre
Tb
General Considerations
•
•
•
•
•
•
•
ID of the pathogen
Drug susceptibility
Drug spectrum
Drug dose
Period of time to affect the pathogen
Site of infection
Patient assessment
Agent Classification
• Narrowspectrum:
• Extendedspectrum:
• Causative agent
known through
culture
• Specific causative
agent not known
General Side Effects
• Hypersensitivity
• Toxicity to various organs:
kidney, liver, skin, bone
marrow
• Suprainfection
General Nursing Implications
• Assess results of C&S or that
culture has been done before
starting antibiotic
• Instruct client to take all
medication
• Use another type of Bc
• Monitor blood levels
– Peak
– Trough
Continued:
• MONITOR CBC (WBC and
differential)
• If severe diarrhea, instruct client to
drink buttermilk/yogurt to replace
flora
• Know difference:
– Bacteriostatic
– Bactericidal
Nursing Process
•
•
•
•
•
Assessment
Nursing Diagnosis
Planning
Intervention
Evaluation
Antibiotics Affecting The
Bacterial Cell Wall
• PENICILLINS:
– Derived from fungus
– Beta-lactam drugs
– Bactericidal
– Penicillin G: narrow spectrum
– Aminopenicillins: broad-spectrum
– Commonly destroys gram +
• Streptococcus, staphylococcus
Major Side Effects
• Most common SE are GI
• Rash on abdomen, scalp, or
arms…usually first sign of allergy
• Hematologic reactions: decreased
hemoglobin, prolonged bleeding
• NSAIDS: protein-bound/compete
• Decreased effect of BCP
Combination Products
• Clavulanic acid, tazobactam,
sulbactam
• Bind to enzyme’s active site and
allow antibiotic to reach target
site
• Augmentin,Unasyn
Cephalosporins
• Introduced in 1960’s
• Similar to penicillins, bactericidal
• 4 generations of drug, each with
different spectrum
• If allergic to penicillins, may be
allergic to cephalosporins (1-18%)
Cephalosporins
• 1st generation
– Gram +
– Skin infections
– take with food to
decrease GI upset
• 2nd generation
– gram + and gram – low cost
– broad range of
organisms
Cephalosporins
• 3rd generation
– Works best against
Gram – severe infections and
immuno-compromised
patients
– SE: bleeding, no
alcohol
– Ceftriaxone
(Rocephin)
• 4th generation
– Active against Gram
+,– highly resistant to to
destruction by betalactamases (both 3rd
and 4th)
– Vancomycin
(Vancocin)
Antibiotics Affecting Protein
Synthesis
• Aminoglycosides
• Macrolides
Aminoglycosides
• Action: severe infections
• Potential for serious AE
– ototoxicity, nephrotoxicity
• Not given orally due to their poor
absorption
• Low dose: bacteriostatic
• High dose: bactericidal
• Use primarily for Gram • Monitor peak and trough
• Gentamicin
Macrolides
• Bacteriostatic and high doses is
bactericidal
• Common AE: GI upset,
hepatotoxicity
• Interacts with warfarin,
cyclosporin, carbamazepine
• Common drugs: erythromycin,
clarithromycin, azithromycin
Tetracyclines
• Inhibit the growth of bacteria, does not
kill them
• Uses: Gram +, -, broad spectrum
• Contraindicated for use in children
under 8, pregnant or nursing women
• Major AE: GI upset, hepatotoxicity,
stained teeth, superinfections
Miscellaneous Antibiotics
• Fluoroquinolones
• Sulfonamides
Fluoroquinolones
• Very broad-spectrum antibiotic.
• Kill rather than inhibit.
• Cipro is most active against aerobic
gram - organisms.
• Not indicated for children under 18 or
pregnant women.
• Adverse effects: arthropathy, GI upset,
HA,
• Give on an empty stomach.
Sulfonamides
• Bacteriostatic
• Primarily used to treat UTI because of
high concentrations in kidneys
• Major AE: nephrotoxicity,
photosensitivity, allergic reactions
• Encourage increase fluid intake, take
on empty stomach
• Sulfamethoxazole-trimethoprm(SMZTMP)-Bactrim)
Antimycobacterials
• Used to treat or prevent TB
infection
• Used in caution with liver disease
or severe renal impairment
• AE: hepatitis, peripheral
neuropathy
• Review diet and alcohol
restrictions
Antiviral
• Acyclovir:
– Treats herpes-viruses; herpes
simplex, herpes zoster, Epstein Barr
virus, CMV
– Effective against actively replicating
viruses
– AE: N/V, anorexia, nephrotoxic
Antifungal
• Amphotercin (Fungizone)
– Wide spectrum of activity against
many fungi
– Can cause anemia, hypokalemia,
hypomagnesemia.
– AE: nephrotoxicity