Flashcards in Anti-Microbials Deck (135)
What is the general goal of antimicrobial therapy in anesthesia?
Inhibit microorganisms at concentrations that are tolerated by the host.
Name two general rules of antimicrobial therapy in anesthesia.
1. For seriously ill/immunocompromised patients select bactericidal.
2. Narrow spectrum before broad spectrum or combination therapy to preserve normal flora.
When we kill a patients normal flora we introduce them to what? Why?
Super infections because the normal flora can secrete "things" that kill opportunistic bacteria.
Name 5 considerations for antimicrobials used for surgical prophylaxis.
1. Weigh the risks/benefits.
2. select cost effective broad spectrum antibiotics
3. Prophylactic antibiotics should be given no more than 1 hour before incision.
4. Usually a single dose but may be continued for 48 hours.
5. No proof that a brief course of antibiotics results in emergence of resistant organisms.
How do we select an antimicrobial? (6)
1. Identify the causative organism.
2. Efficacy depends on drug delivery to site.
3. Usually treat with a single drug
4. Route of administration
5. Duration of treatment
Name two considerations that may interfere with the efficacy of a drug to a particular site.
1. transport across the BBB varies greatly
2. More effective if infected material is removed..
Are hypersensitivity reactions dependent or independent of the dose?
Are drug toxicities dependent or independent of the dose.
Dependent (dose related)
What special considerations must be made with a parturient when determining the proper antimicrobial? (2).
1. Most antimicrobials cross the placenta and enter into maternal milk. Fetus's liver is immature and they can't metabolize or excrete that drug and could end up with toxicity. For milk mom should discard the first couple rounds.
2. Teratogenecity- the malformation of an embryo or fetus that we worry about with any drug.
What special considerations must be made with an elderly person when determining the proper antimicrobial? (4).
1. Renal impairment
2. Deceased plasma proteins
3. Reduced gastric motility and acidity
4. Increased body fat.
Killing the bacteria
Preventing the bacterium from reproducing, does not necessarily kill/damage the bacteria.
Is PCN bacteriostatic or bactericidal?
How does PCN kill the bacteria?
By interfering with the cell wall. Doesn't allow the cell wall to join correctly and interferes with an enzyme that keeps the cell wall stable.
What three organisms (did Denise mention) that PCN is effective against?
How is PCN excreted?
PCN is part of what family of antimicrobials?
What is the big difference between PCN and ampicillin?
Ampicillin has a wider range of activity including gram negative bacilli (H. influenzae and E coli)
Of the PCN class which has the highest incidence of a skin rash?
What is the main difference between amoxicillin and ampicillin?
Amoxicillin is more efficiently absorbed from the GI tract than ampicillin.
What is the most common side effect of the PCN class? What symptoms can be seen?
Rash and or fever, immediate anaphylactic reaction and rarely hemolytic anemia
How long can the hypersensitivity reaction from PCNs be delayed?
up to 24 hours.
Of all the microbials which is the most allergenic?
The PCN family.
Which class of drugs exhibits cross-sensitively with PCNs?
Are cephalosporins bactericidal or bacteriostatic?
How do cephalosporins kill the bacterium?
Inhibits cell wall synthesis.
What larger family are the cephalosporins a part of?
What kind of spectrum of action do cephalosporins exhibit?
How are cephalosporins excreted?
60% through the kidneys
40% through the bile