Principals of pharmacology- medical .ppt

Copyright © 2011 Delmar, Cengage Learning. ALL RIGHTS RESERVED.
UNIT 15
Antibiotic Agents

Key Terms
• Antiseptic
• Bacteria
• Bactericidal
• Bacteriostatic
• Beta-lactamase
• Disinfectant
• Infection
• Microorganism
• Pathogen

Infectious Disease
• Viruses cause 50% of all infectious
diseases
• Infectious disease is one of the world’s top
three killers (with heart ailments and
cancer)
(continues)

Infectious Disease
• Factors for infection
– Organism in sufficient number
– Power and degree of pathogenicity
– Environmental conditions
– Portal of exit
– Mode of transmission
– Susceptible host
(continues)

Infectious Disease
• Defense mechanisms
• Body equipped with built-in defense
– Intact skin
– Secretions
– White blood cells
– Body chemicals
– Antibodies

Deadly Infection Factors
• International travel and food shipment
• Population growth
• Changes in growing and handling of food
• Poor public health infrastructure
• Immunosuppression
• Increased use of antibiotics in humans and
livestock
• Resistance to antibiotics

MRSA
• Bacteria is resistant to antibiotics
• Frequently occur in people in health care
centers with compromised immune systems
• (CA)-MRSA: usually skin infections
– 5 Cs: crowding, frequent skin-to-skin contact,
compromised skin, contaminated items, lack of
cleanliness

C. difficile
• Majority occur in health care settings
• Antibiotic resistant
• Toxins attack intestinal lining
• Treat with Flagyl or Vancocin

Escherichia coli
• Normally found in human intestine
• May cause diarrhea, hemorrhagic colitis, and
HUS
(continues)

Escherichia coli
• Contamination by
– Ground beef
– Fruits and vegetables
– Swimming pools, hot tubs
Did you know?
E. coli is the most common
cause of UTI in women.

Salmonellosis
• Infects intestines and blood
• Most recover without treatment, but some
require hospitalization
• May cause diarrhea, fever, abdominal
cramps; usually lasts 4 to 7 days
• 40,000 cases per year; 1,000 deaths per year
(continues)

Salmonellosis
• Usually foodborne
– Raw poultry
– Eggs
– Unpasteurized milk and cheese
• Infected food handlers
• May be found in animal feces
(continues)

Salmonellosis
Discussion Questions:
Why is salmonellosis more common in
summer than in winter?
What can be done to prevent infection
with E. coli or salmonellosis?

Campylobacteriosis
• Most common bacterial cause of diarrhea in
the United States
• Symptoms
– Diarrhea, may be bloody
– Cramping
– Nausea and vomiting
– Fever
(continues)

Campylobacteriosis
• Transmission
– Contaminated food, water, or milk
– Undercooked poultry
– Cross-contamination from raw to ready-to-eat food

SARS
• SARS: Severe acute respiratory syndrome
• First reported in Asia in February 2003
• 8,098 diagnosed; 744 died
• Viral infection spread through droplets
• Possibly airborne-spread
(continues)

SARS
• Symptoms
– High fever
– Headache
– Overall discomfort; body aches
– Dry cough
– Diarrhea
– Pneumonia develops in most of those infected

Streptococcus
• Group B
– Most common cause of sepsis and meningitis in
newborns
• Group A
– Found in throat and on skin
– May cause strep throat, impetigo, necrotizing fasciitis, or
streptococcal toxic shock syndrome (STSS)

Group A Streptococcus (GAS)
• Necrotizing fasciitis: “flesh-eating bacteria”
– Destroys muscle, fat, and skin
– 20% of patients die
• STSS
– Causes hypotension and organ failure
– More than 50% of patients die

Minimizing Your Risk
• Healthy diet
• Don’t smoke
• Reduce stress
• Exercise
• Adequate sleep
• Current immunizations
(continues)

Minimizing Your Risk
• Adequate fluid intake
• Positive attitude
• Good hygiene
• Don’t share food or drink with others
• Keep hands away from face

Warning!
Seek medical attention immediately
• Sudden high fever, violent chills, or confusion
• Infection seems to be spreading
• Injury becomes extremely painful or enlarges
• Redness or blistering of skin
• Pain in muscles
• Enlarged lymph nodes
• Crescendo pain in surgical incision
• High fever, vomiting, lethargy, inflammation in other
areas, or swollen areas of body after fourth day of
chickenpox
• Pregnant women with flu-like symptoms

Antibiotics
• Used to treat bacterial infections in
animals, plants, humans
• Bacteria
– Gram-positive: retains gentian violet stain
– Gram-negative: does not retain gentian violet
stain
– Acid-fast: retains stain even when treated with
acid
(continues)

Antibiotics
Discussion Questions:
How can keeping a positive attitude help prevent
infection?
If patients are no longer contagious after 24
hours of antibiotics, why must they continue to
take medication for several days?

Classification of Antibiotics
• Broad-spectrum
– Many kinds of microorganisms
• Narrow-spectrum
– Limited types of microorganisms
• Extended-spectrum
– Covers Pseudomonas, Enterobacter, and Proteus species

Administration of Antibiotics
• Check for allergies; note in red
• Culture and sensitivity should be performed
BEFORE starting antibiotics
Discussion Question:
Why would you not perform a C&S after
antibiotics have been administered?

Effective Antibiotics
• Must be harmless to blood, liver, bone
marrow, and kidneys
• Low possibility of toxicity
• Effective against invading microorganism
• Must be more beneficial than harmful

Adverse Reactions to Antibiotics
• Hypersensitivity
• Organ toxicity
• Superinfection
• Antibiotic overuse
– Results in drug-resistant strains of bacteria

Antibiotic Resistance
• Use of antibiotics for viral infections
increases antibiotic resistance
• Antibiotics are overprescribed
• Hand washing and avoiding close
contact with others limits spread of viral
infections

Broad-Spectrum Antibiotics
• Penicillins
• Cephalosporins
• Carbapenems
• Tetracyclines
• Aminoglycosides
• Macrolides

Penicillins
• Special considerations
– Take on empty stomach
– Take with 8 oz water
– Do not take with soft drinks, fruit juice, or wine
– Administration with erythromycin or tetracycline may
diminish effectiveness

Cephalosporins
– Take on full or empty stomach
– May be crushed or mixed with food
– May cause false urine sugar test results
– Avoid alcohol consumption
(continues)

Cephalosporins
Warning!
Cephalosporins may interact with alcohol, causing an
Antabuse-like reaction
• Flushing or syncope
• Chest pain and palpitations
• Arrhythmias and tachycardia
• Hypotension

Carbapenems
• Contraindications
– Known hypersensitivity to same class of drugs
– Patients with demonstrated anaphylactic
reactions to beta-lactams

Tetracyclines
– Children under 8 years of age
– Pregnancy or lactation
– Renal or liver impairment
(continues)

Tetracyclines
• Special Considerations
– Permanent discoloration of deciduous teeth
– Take on empty stomach with 8 oz water
– Do not take with dairy products, calcium, antacids, or iron

Aminoglycosides
– Labyrinthine disease
– Myasthenia gravis
– Pregnancy or lactation
– Cautious use in renal impairment, elderly, infants, or
children
(continues)

Aminoglycosides
– Can cause permanent damage to acoustic nerve
– Observe for ototoxicity or nephrotoxicity
– Drink plenty of liquids to reduce development of
nephrotoxicity

Macrolides
• Ketolides
– Telithromycin
• Erythromycin
• Azithromycin
• Carithromycin
(continues)

Macrolides
Warning!
Grapefruit juice decreases the speed at which the body breaks down
certain medications. Drinking grapefruit juice can increase the effects and
side effects of these drugs.
Erythromycin can decrease the effectiveness of combination-type birth
control pills.

Other Antibiotics
• Fluoroquinolones
• Monobactams
• Oxazolidinones
• Streptogramins
Warning!
Fluoroquinolones are associated with increased risk of tendonitis and tendon
rupture. This risk is further increased for those older than 60; in kidney,
heart, and lung transplant recipients; and with use of concomitant steroid
therapy.

Antiseptics and Disinfectants
• Antiseptics
– Used on skin and body tissues
– Prevent or inhibit microorganism growth
– Bacteriostatic actions
• Disinfectants
– Used on objects and surfaces
– Kill vegetative forms of microorganisms
– Bactericidal action
(continues)

Antiseptics and Disinfectants
 Effectiveness depends on
– Strength and temperature of solution
– Time of exposure
– Ionization rate of substance

Bleach
 Recommended by OSHA more than any other
disinfectant in medical and dental practices
 Replace solution every 2 to 3 days
 Inactivate HIV with 10% solution
 Decontaminate surfaces with 1% solution

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