Antimicrobial Therapy Flashcards
The ability of a drug to injure a target cell or target organism without injuring other cells or organisms that are in close contact with the target.
Selective Toxicity
Antibiotics work one of three ways. What are they:
- ) disruption of the bacterial cell wall (bactericidal)
- ) Inhibition conversion of an enzyme unique to the bacteria.
- ) disruption of protein synthesis in bacterial ribosomes (bacteriostatic)
Bactericidal:
Agent that kills bacteria.
Bacteriostatic:
Agent that inhibits bacterial growth and replication.
What class of drugs are considered bactericidal?
Penicillins, Cephalosporins, and glycopeptide
What class of drugs are considered bacteriostatic?
Tetracyclines, Marcolides, Aminoglycosides, Sulfonamides, Fluoroquinolones, Metronidazole.
This is the process of choosing an antibiotic without identifying the infectious organism.
Empiric Therapy
Narrow spectrum:
Have a narrow focus. More specific to the type of bacteria.
Broad Spectrum:
Not specific for a bug but can kill what is suspected. Effective against a wide range of bacteria.
Steps for “matching the drug to the bug?”
- ) perform a culture
- ) broad spectrum
- ) get your results
- ) narrow spectrum
Prophylactic Therapy:
Antibiotics are given when patients are scheduled for procedures in which there is a strong possibility of microorganism presence.
Guidelines for prophylactic therapy:
Give 30 - 60 minutes before surgery time/ before incision time.
Penicillin’s weaken the cell wall. Examples of these drugs include:
Ampicillin and Amoxicillin
Penicillin drugs end in :
-cillin
Mechanism of action of Penicillins:
Bactericidal. Kill gram + and gram - bacteria by inhibiting bacterial cell wall synthesis (weakens cell wall).
Uses of Penicillins:
Drug of choice for syphilis, meningitis, and streptococcus pneumonia.
Newer and stronger versions of Penicillins:
Augmentin and Zosyn
Adverse effects of Penicillins:
- most common cause of drug allergy.
- minor rash to full blown anaphylaxis
- caution use with renal dysfunction patients
- can increase risk for bleeding
What drug should not be given with Penicillins?
Aminoglycoside (Gentamicin)
What drug enhances the effects of Penicillin?
Probenecid (drug for gout)
If patient has a mild allergic reaction to Penicillin what other Bactericidal drug can we give them?
Cephalosporin (ex: Ancef) orally
If patient has a severe allergic reaction to Penicillin what do we as the nurse consider?
That the patient is also allergic to cephalosporin as well.
If patient has a severe allergic reaction to Penicillin what med do we give to them instead?
- vancomycin
- erythromycin
- clindamycin
Cephalosporins start with:
+cef, +ceph
Cephalosporins Mechanism of action:
Bactericidal. Interfere with bacterial cell wall synthesis.
There are five generations of Cephalosporin drugs now available. What do the generations indicate?
The higher the generation, the more resistant (stronger) against beta lactamases produced by bacteria.
Drug examples of Cephalosporins include:
Cefazolin and Ceftriaxone
Cephalosporins uses:
Active against gram + and gram - and some anaerobic bacteria.
Side effects of Cephalosporins:
Mild diarrhea, abdominal cramps, rash, pruritis, redness and edema. Interferes with vitamin K so increase risk for bleeding.
What should you not use while taking Cephalosporins?
Do not use alcohol (causes Disulfiram reaction)
Drug example of Glycopeptide:
Vancomycin
Vancomycin mechanism of action:
Inhibits cell wall synthesis (bacterial cell lysis and death)
Vancomycin uses:
Narrow spectrum; active only against gram + bacteria. Used for pseudomembranous colitis caused by C diff and MRSA infections
Adverse effects of Vancomycin:
Renal failure.
Ototoxicity.
Thrombophlebitis.
Red man syndrome
Bacteriostatic drugs that inhibit protein synthesis include:
Tetracyclines and Macrolides
Tetracycline drugs end in what?
-cycline
Macrolide drugs end in what?
-mycin
Tetracyclines mechanism of action:
inhibits microbial protein synthesis.
Uses for Tetracyclines?
Lyme disease H. pylori Chlamydia Mycoplasma pneumonia Rocky mountain fever acne control
What medication class is an alternative agent for gonorrhea and syphilis?
Tetracycline
Adverse effects of Tetracyclines?
- GI irritation (give with food)
- Can cause yellowing /browning of teeth in kids.
- can lead to superinfections (C difficile and candida albicans)
- Photosensitivity
Tetracycline drug interactions:
- should not be taken with calcium or magnesium.
- reduces the effectiveness of bactericidal antibiotics
- increases BUN and may lead to renal toxicity
Patient education of Tetracycline:
- Pregnant women should not take this medication.
- med should not be taken with meals that have calcium or magnesium.
- can cause yellowing/browning of developing teeth in kids.
Macrolides mechanism of action:
Broad spectrum Bacteriostatic but may be bactericidal in high enough concentrations.
Uses for Macrolides:
- Upper and lower respiratory infections.
- skin and soft tissue infections
- syphilis
- Lyme disease
- gonorrhea
- Chlamydia
- Legionella
Macrolides adverse effects:
- GI effects but can be reduced by taking with meals.
- QT prolongation and sudden death
Macrolides drug interactions :
-Increase plasma levels of Theophylline , Tegretol, and Warfarin (coumadin).
