Exam II: Antibiotics (Protein synthesis inhibitors + others) Flashcards
Erythromycin, clarithromycin, azithromycin.
Antibiotic class?
Macrolides
Name the macrolide that does not end in “mycin”.
Fidaxomicin
These two macrolides are modifications of erythromycin. What aspects of this drug have they improved?
Azithromycin and Clarithromycin
Improve oral absorption, half life, spectrum of activity and potency
Structures contain 14-member macrocyclic lactone ring.
Name antibiotic class.
Macrolides “mycin”
Three antibiotic drug classes that inhibits protein synthesis by binding to 50S ribosomal subunit.
Macrolides “mycin” except Fidaxomicin
Oxazolidinones “zolid”
Pleuromutilins “mulin”
Most antibiotics that are protein synthesis inhibitors are bactericidal or bacteriostatic? Name exceptions.
Most are bacteriostatic
except aminoglycosides “mycin or micin”
Antibiotic ending in “mycin” can be one of two types of antibiotics.
Aminoglycosides
Macrolides (3 drugs)
This class of antibiotics is first choice for community-acquired pneumonia.
Macrolides “mycin”
Erythromycin, clarithromycin, azithromycin
Can treat H.pylori, pertussis (whooping cough) certain STDs. Name the drug class.
Macrolides “mycin”
Erythromycin, clarithromycin, azithromycin
This is the only macrolide used to treat gastroparesis.
Erythromycin
This macrolide can cause dysgeusia (taste disturbances) as a side effect.
Clarithromycin
Antibiotic classes that can cause QT interval prolongation.
Macrolides “mycin”
Lipoglycopeptides “vancin”
What is Torsades de Pointes?
A possible side effect of certain antibiotics that prolong QT interval.
Ventricular arrhythmia
Two macrolides most likely to have drug-drug interactions.
Erythromycin and clarithromycin
Macrolides can interact with amiodarone. What is the possible effect? (Cardiac)
Both are QT prolonging agents
This drug is one of the first to be found to cause an increased risk for C. diff infection.
Clindamycin
These two drugs discussed so far can treat C. diff infections.
PO Vancomycin
PO Fidaxomicin
This drug inhibits protein synthesis in bacteria and can also inhibit toxin production in necrotizing infections.
Clindamycin
Why do some aminoglycosides end in “mycin” while others end in “micin”?
Derived from two different bacteria
Streptomyces - mycin
Micromonospora - micin
Mechanism of action for aminoglycosides. Are they bacteriostatic or bactericidal?
Inhibit protein synthesis by binding to 30S ribosomal subunit
Bactericidal
Aminoglycosides even have a post antibiotic effect. What does this mean?
Even when levels become undetectable, they still exert antibacterial activity
What does the MIC line represent on a graph for bactericidal antibiotics?
Minimum inhibitory concentration - varies per drug
The lowest concentration (in μg/mL) of an antibiotic that inhibits the growth of a given strain of bacteria
Time-dependent antibiotics vs concentration-dependent antibiotics.
Time-dependent antibiotics - greater effect when administered frequently. Longest duration over MIC.
Concentration-dependent antibiotic - greater effect with higher dose. Greatest peak over MIC.
Can an antibiotic be both time and concentration dependent?
Yes, an antibiotic can be both time and concentration dependent.
Antibiotics are considered broad spectrum for gram negative bacteria when they target what bacteria specifically?
Pseudomonas aeruginosa
This drug class is broad spectrum and treats gram negative bacteria Pseudomonas aeruginosa.
Aminoglycosides “mycin”
This drug class has a minimal effect on gram positive bacteria when used alone.
Aminoglycosides “mycin”
Gram positive only.
Name drug classes.
Glycopeptides “Vancomycin”
Lipopeptide “Daptomycin”
Lipoglycopeptides “vancin”
Oxazolidinones “Zolid”
Aminoglycosides are ______ - dependent bactericides.
Concentration-dependent
Nephrotoxicity and Ototoxicity (ear damage)
Name drug class. Reversible or irreversible?
Aminoglycosides
Nephrotoxicity - reversible
Ototoxicity - irreversible
What are the two dosing strategies for aminoglycosides?
- High dose over an extended period of time.
2. Small doses given more frequently
Two drug classes with narrow therapeutic index that require monitoring.
Aminoglycosides “mycin”
Glycopeptides “vancomycin”
This drug is the “workhorse” for serious gram- positive infections in hospital settings.
Glycopeptide
Vancomycin
Name the antibiotic dubbed “mississippi mud” originally due to impurities.
Glycopeptide
Vancomycin
Glycopeptide “Vancomycin” moa. Bacteriostatic or bactericidal?
Inhibits cell wall synthesis by binding to D-alanyl-D- alanine terminus of cell wall precursors
Bactericidal
Glycopeptide “Vancomycin” is a ______- dependent bactericide.
Time-dependent and concentration-dependent activity
What two antibiotics can treat VRE infections?
Linezolid
Daptomycin
What does VRE stand for referencing antibiotics?
Vancomycin- resistant enterococci
Some strains of Enterococci have become vancomycin resistant.
IV vs PO Vancomycin. Name the difference in infections these are used to treat.
IV Vancomycin - Serious gram-positive infections
PO Vancomycin - C. Diff infection
What is “Red man syndrome” and how can it be avoided?
Histamine-mediated infusion reaction, not an allergic reaction.
Limit infusion rate to avoid reaction.
Fidaxomicin is a macrolide. Does it have the same moa as the others?
Fidaxomicin - Inhibits bacterial RNA polymerase
Other Macrolides (Erythromycin, clarithromycin, azithromycin) - Inhibit protein synthesis by binding to 50S ribosomal subunit.
Which drug out of the two discussed to treat C. diff has a reduced rate of infection? Why?
Fidaxomicin
Drug possibly does a better job of preserving good bacteria in the gut
Lipopeptide “Daptomycin” moa. Bactericidal or bacteriostatic?
Binds to cell membrane and causes rapid depolarization
Bactericidal
Any antibiotic with gram positive activity has an FDA approval for what clinical use?
Skin and soft tissue infections
Why can’t Daptomycin be used to treat pneumonia?
It is inactivated by pulmonary surfactant
Daptomycin is only administered?
IV only
Compare lipoglycopeptides “vancin” to vancomycin.
Longer half-lives than vancomycin
Increased potency than vancomycin
Lipoglycopeptides “vancin” moa. Bacteriostatic or bactericidal?
Inhibits cell wall synthesis by binding to D-alanyl-D- alanine terminus of cell wall precursors - Same as Vancomycin
Bactericidal
Additional moa that Telavancin and Oritavancin but Dalbavancin does not.
Disrupt cell membrane integrity
The two lipoglycopeptides “vancin” administered as a single dose due to long half life.
Dalbavancin
Oritavancin
The only lipoglycopeptide “vancin” that can treat disorders other than skin and soft-tissue infections.
Name the disorders.
Telavancin
Hospital-acquired pneumonia,
ventilator-associated pneumonia
Bacteremia
Lipoglycopeptide “vancin” are only administered?
IV only
Oxazolidinones “zolid” moa. Bactericidal or bacteriostatic?
Inhibits protein synthesis by binding to 50S ribosomal subunit
Bacteriostatic
Oxazolidinone “zolid” most likely to interact with preserotonergic drugs.
Linezolid
Pleuromutilins “Lefamulin” moa. Bacteriostatic or bactericidal?
Inhibits protein synthesis by binding to 50S ribosomal subunit
Bactericidal or bacteriostatic
