Abx overview Flashcards
Which of the four MOAs of antibacterials do we use the most?
inhibition of DNA synthesis and integrity
List the 3 inhibitors of cell wall synthesis
- Beta-Lactams: PCN
- Cephalosphorins
- Glycopeptides: Vancomycin
List the 4 inhibitors of translation of transcription
- Tetracyclines: Doxycycline
- Macrolides: Z-pack
- Clindamycin
- Oxazolidinones: Linezolid
List the 3 inhibition of DNA synthesis and integrity/inhibitors of folate synthesis and function
- Sulfonamides
- Trimethoprim
- Quinolones
Mechanism of bactericidal
Ability to kill
-Inhibition of cell wall synthesis
List the time-dependent abx
- Beta-Lactams: PCN
2. Vancomycin
List the concentration-dependent abx
- Aminoglycosides
2. Quinolones
Bacteriostatic mechanism
Inhibition of protein synthesis
-Slow the microorganism down
List the bacteriostatic abx
- Tetracyclines: Doxycycline
- Macrolides
- Sulfonamides
What do we have to use in immunocompromised pt’s?
Bactericidal
What would be a appropriate combination for empiric therapy?
two bactericidals
Postantibiotic effect
Persistent suppression of bacterial growth after limited exposure (1-2 hrs) to an antimicrobial agent
Abx contraindicated in renal impairment
- Sulfonamide (long-acting)
- Tetracyclines
- Nitrofurantoin
Dosage adjustment needed in hepatic impairment
- Z-Pack
2. Clindamycin
List penicillinase-susceptible abx (narrow spectrum)
Penicillin VK
List penicillinase-resistant abx
Nafcillin: S. aureus
List a wider spectrum abx that is +/- penicillinase
Amoxicillin
What additional microorganisms are covered by Amoxicillin, but not by PCN?
Gram negatives: H.influenza
How is PCN cleared?
Renally
What PCN are biliary cleared?
Ampicillin
Nafcillin
PCN adverse side effects
- Hypersensitivity rxs: angioedema
2. Maculopapular rash: Ampicllin
What organisms do narrow spectrum PCN cover?
- Streptococcal infections
2. Staphyloccocal infections
What organisms do wider spectrum PCN cover?
Greater activity vs. gram (-) bacteria
What cephalosporin crosses the blood brain barrier and are used for CNS infections?
3rd generation: Ceftriaxone
-Treat meningitis
What generation has partial cross-reactivity with PCN?
First generation: Cephalexin
What cephalosporin is not given to newborns and why?
Ceftriaxone (Rocephen)
-Cleared by biliary tract, newborns don’t have this ability yet
First generation cephalosporin name and clinical use
Cephalexin:
- Skin
- Soft tissue
- UTI
Second generation cephalosporin name and clinical use
Cefuroxime:
More active against:
1. S. pneumoniae
2. H. Influenza
What cephalosporin has remained susceptible to Gonorrhea since the Vietnam War?
Ceftriaxone
Fourth generation clinical use
Pseudomonas coverage
Fifth generation clinical use
- Community acquired pneumonia
2. MRSA
What monobactam has no cross-allerginicity with beta-lactams?
Aztreonam
What is the go to drug for MRSA and PRSP strains?
Vancomycin
How would you administer Vancomycin for systemic infections?
Parenteral
What is effective against C. diff and how is it administered?
Vancomycin
ORALLY!!!!!
Red neck or red man syndrome
erythematous rash on face and upper body from giving the vancomycin infusion too quickly
Daptomycin gram positive activity
- Endocarditis
- Sepsis
- MSSA and MRSA coverage
Daptomycin off-tabled use?
- Osteomyelitis
2. Prosthetic joint infections
Daptomycin unique toxicity?
Myopathy
-Monitor creatinine pho shop-kinase (CPK) weekly
Tetracycline (Doxycycline) MOA
- Inhibits bacterial protein synthesis
- Binds 30s subunits of transcription/translation
- Bacteriostatic
Tetracycline (Doxycycline) activity spectrum
- Chlamydial
- Mycoplasma: “walking pneumonia”
- Rickettsiae
- Spirochetes (Lyme disease)
Why don’t we want to give Tetracycline (Doxycycline) to a child under 8 y.o. or a child developing in pregnancy?
Deposits in developing bones and teeth
What does Brubaker recommend you take with Tetracycline (Doxycycline)? Why?
Cola: Natural anti-emetic effect
A unique adverse side effect of Tetracycline (Doxycycline)?
Photosensitivity- Wear sunblock
Macrolides MOA
- Inhibit bacterial protein synthesis
2. Bacteriostatic
Why do Macrolides cause diarrhea?
Prokinetic effect= Increases GI motility
Erythroymycin (Z-pack) side effects
- QT prolongation
- CYP450 inhibition (not azithromycin)
- Resistance gaining
Macrolides activity spectrum
- Community acquired pneumonia
- Pertussis
- Diptheria
- Chlamydial
What abx has the highest INCIDENCE of C.diff?
Clindamycin (lincosamides)
What has the highest PREVALENCE of C. diff?
Amoxicillin
Cephalosporins
What is unique about Clindamycin (lincosamides)
Anaerobic infections=diaphragm up
What can cause dose-related anemia (aplastic anemia) requiring a bone transplant?
Chloramphenicol
Chloramphenicol activity spectrum
- Tx of serious infections due to organisms resistant to less toxic abx
- Active against Vancomycin-resistant enterococci (VRE) **
Gray baby syndrome
Adverse rxn of Chloramphenicol
- Circulatory collapse
- Cyanosis
- Acidosis
What abx causes Serotonin Syndrome with SSRIs?
Oxazolidinone (Linezolid)
Often with dosage adjustment
Oxazolidinone (Linezolid) activity spectrum
- MRSA
- PRSP
- VRE strains
What is a great example of empirical abx therapy drug combo?
Aminoglycosides + Beta-Lactams
List the aminoglycosides
- Gentamycin
2. Tobamyccin
aminoglycosides ADE’s
- Ototoxicity (irreversible)
- Neuromuscular blockade**
- Nephrotoxicity (reversible)
Who do we give high dose folic acid to?
Spinal tubal defects
“Sequential blockade” in Sulfonamides with Trimethoprim
Combination is bactericidal
-Synergistic inhibition of folic acid synthesis
What is the dosing based on in TMP-SMZ?
trimethoprim component
TMP-SMZ (Bactrim) Acitivity spectrum
- UTI
2. MSSA or MRSA (skin/soft tissue infections)
What stage of pregnancy should TMP/SMX be avoided?
Frist trimester
-This is when the spinal tube is forming
List the Quinolones and uses of each
- Ciprofloxacin- UTIs
2. Levofloxacin- “respiratory”
In what neuromuscular disease should quinolones be avoided?
MYASTHENIA GRAVIS and Neuromuscular blockers before surgery
Other ADE’s of Quinolones (many, she hates this drug)
- CNS effects**
- Achilles tendinitis**
- Neuromuscular-blocking activity
What does an antibiogram provide?
- Info about local resistance patterns
2. Can be used to determine empiric tx options