What you really need to know for ABX Flashcards
MOA of Beta Lactams
Bind to PCN binding protein, cell wall synthesis inhibitor
MOA of Fluoroquinolones
Inhibit DNA synthesis through competitive binding
“unzips the genes”
MOA of Tetracyclines
Irreversibly binds to 30s ribosomal unit which inhibits protein synthesis
MOA of Cephalosporins
Bind to PCN binding protein. Cell wall synthesis inhibitor
MOA of Macrolides
Binds to the 50s ribosomal subunit targeting 23S ribosomal RNA…. inhibits protein synthesis
MOA of Aminoglucosides
Irreversibly binds to 30s ribosomal subunit causing misreading of mRNA cell wall damage
MOA of Carbapenems/Monobactams
Bind to PCN binding protein, cell wall synthesis inhibitor
Which class covers Gram positive, but has increasingly more Gram negative coverage with each newer generation?
Cephalosporins
Which class covers Gram negative, including pseudomonas?
Aminoglucosides
What is the ABX of choice for ESBL’s?
carbapenems
T/F: Beta Lactams cover primarily Gram Positive?
True
What do carbapenems/monobactams cover?
Most aerobic/anaerobic gram pos/neg including pseudomonas
What do macrolides primarily cover?
Respiratory organisms
What do tetracyclines cover?
A lot of gram pos/neg
T/F: Fluoroquinolones cover primarily Gram Positive?
False; gram neg
Which classes are bactericidal?
- Beta lactams 2. Cephalosporins 3. Carbapenem/Monobactams 4. Fluoroquinolones 5. Aminoglucosides
Which classes are bacteriostatic?
- Macrolides 2. Tetracyclines
Which classes are safe for renally impaired patients?
- Macrolides 2. Tetracyclines 3. Aminoglucosides
Examples of Beta lactams?
- PCN 2. Ampicillin 3. Amoxicillin 4. Piperacillin
What is the most frequently used class of ABX?
Cephlapsorins
How do cephlasporins compare to PCN’s?
Same MOA as PCN (bacteriocidial), but Less suspectible to beta lactamase than PCN’s
Examples of Cephalosporins?
1st gen: cefazolin
2nd gen: cefoxitin
3rd gen: Ceftriaxone and ceftazidime
4th gen: Cefepime
5th gen: Ceftaroline
With cephlasporins, you get better gram ___ with lower gens and better gram ___ with higher gens
positive
negative
When should Cefazolin be redosed?
- Redose Q4hrs (2 half-lives)
- If EBL >1.5L
How does 2nd gen cephs compare to 1st gen?
Less gram +, more gram -
add in h.influenza, enterobacter, and Neisseria
Good safety profile and hypersensitivy
Used alot for respiratory infections
Which generation cephlasporins are assoc. with CBC abnormalities?
1st gen
Which generation cephlasporins are used for respiratory infections/community acquired PNA?
2nd gen, specfically Cefuroxime (Ceftin)
Which generation cephalosporins crosses the blood brain barrier?
3rd gen: ceftriaxone and ceftazidime
Hence, these are good for meningitis
Which generation cephalosporin covers MRSA?
5th gen: Ceftaroline
Which 3rd gen cephlasporin has 50% renal elimination and significant biliary excreiton?
Cefotaxime (Claforan)
Which 3rd gen cephlasporin can cause diarrhea, biliary sludging, and precpipiate with calcium?
Ceftriaxone (Rocephin)
What electrolyte abnormality is assoc. with 3rd gen PCN’s (timentin and zosyn)?
Hypokalemia
ticarcillin is also associated with hypernatremia in the elderly
Which generation cephlasporins increase bleeding time?
3rd gen
What are two important points that Emily talked about withn Ceftazidime (Fortaz)?
most gram negative with good Pseudomonal coverage; less gram positive and anaerobic than other 3rd gens.
When would you use 4th gen ceph ABX like Cefepime (Maxipime)?
ESBL’s, Pseudomonas and Enterobacteriaceae that are resistant to 3rd gen cephs
Which generation cephalosporin covers pseudomonas?
3rd gen: Ceftriaxone and ceftazadime
ceftazadime = “taz”manian devil which kills everything
What med when added to a 3rd gen ceph gives you significant gram negative coverage and would be good for ESBL’s?
avibactam (Avycaz)
Avycaz is ceftazidime/avibactam added together.
Which drug has the second highest chance of causing C Diff?
Cefazolin
T/F: Cefazolin covers MRSA
False
Examples of Carbapenems?
“penems” 1. Imipenem (cilastatin) 2. Meropenem 3. Erapenem
What patients are carbapenems contraindicated in?
Pts with seizure disorder or head injury at increased risk of seizure
Which carbapenem has the lowest risk of seizures? Which has the highest?
lowest = Ertapenem (Invanz)
highest = Imipenem/Cilastatin (Primaxin)
What two non-ABX meds greatly increase the risk of seizures in combo with Imipenem/Cilastatin (Primaxin)?
Ultram and Wellbutrin
How is monobactam different from carbapenems?
Same MOA as carbapenems, but no seizure risk
Ex.Aztreonam (Azactam)
Examples of Monobactam?
Aztreonam
MOA of Vanco
Inhibits peptidoglycan formation; disrupts cell wall synthesis; bactericidal
Is Vanco concentration or time dependent?
Concentration
dose to trough levels
Does Vanco cover gram negative?
No, gram postive only.
So you wont get E.Coli coverage
Do get MRSA coverage
Vanco is ____ eliminated
Renally
What are the 4 major adverse effects of Vanco?
Red man syndrome
Nephrotoxocicty
Ototoxicity
TTP
With vanco, is red-man syndrome a true allergic reaction?
No, its infusion rate related. Once you slow down the infusion rate (no more than 1g/hr), it should decrease
can treat with anti-histamines if really bothering the pts
What is a good alternative to vancomycin?
Linezolid
Esp for VRE and MRSA, covers “blind spots” that vanco has
MOA of Linezolid (Zyvox)
Bacteriostatic
Per Emily, know that it slows down/inhibits ribosomal formation of 50S subunit and that it is NOT a cell wall synthase inhibitor
What are the adverse effects with Linezolid (Zyvox)?
Myelosuppression (anemia, leukopenia, pancytopenia, thrombocytopenia (very often))
Will see drops in CBC values
Linezolid (Zyvox) has potential drug interaction with ___, so hold ____ meds because of the risk of _____ syndrome
MAO’s inhibitors
Antidepressant
serotonin syndrome (looks like MH)
What is drug of choice for legionnaires?
Erythromycin
Which macrolide has the most GI toxicity side effects?
Erthromycin
Examples of Macrolides?
“Mycins”
- Azithromycin 2. Biaxin 3. Erthromycin
What is drug of choice for bacterial GI infections?
Ciprofloxacin
Examples of fluorquinolones?
- Ciprofloxacin 2. Levofloxacin 3. Ofloxacin 4. Moxifloxacin 5. Delafloxacin
Which fluoroquinolone can treat MRSA?
Delafloxacin
Which fluorquinolone does not have risk of QT prolongation or photosensitivity?
Delafloxacin
Examples of Tetracyclines?
- Doxycycline 2. Tigecycline
Examples of Aminoglucosides?
- Amikacin 2. Gentamicin
Can Gentamicin be used for gram positive organisms?
Yes; but must be used with cell wall destructive agent as well.
Adverse effects of Beta lactams?
- N/V/D for all of them. Newest gen (ticaricillin and piperacillin) 1. prolong bleeding time 2. hypokalemia
Adverse effects of cephalosporins?
N/V/D
Which cephalosporin produces biliary sludging?
Ceftriaxone