Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
82 Cards in this Set
- Front
- Back
|
What is the only Lincosamide?
|
Clindamycin
|
|
|
What is the mechanism of action of clindamycin (a lincosamide)?
|
BLOCKS TRANSLOCATION of peptidyl-tRNA from acceptor to donor site by binding to the 50S SUBUNIT
**Same as MOA as Macrolides! |
|
|
Is clindamycin available IV or orally?
|
BOTH: IV And Oral
|
|
|
Use of clindamycin is associated with what clinical superinfection and disease?
|
diarrhea and colitis due to C. DIFFICILE PSEUDOMEMBRANE COLITIS.
|
|
|
Is clindamycin bacteriostatic or bactericidal?
|
bacteriostatic.
|
|
|
What are the clinical uses of clindamycin?
|
gram- NEGATIVE ANAEROBIC severe infections:
-Bacteroides fragilis -combination therapy with aminoglycosides for intra-abdominal infections |
|
|
Act on 50S subunit?
|
chloramphenicol, macrolides, oxazoladinones, lincosamides, streptogramins
|
|
|
Act on 30S subunit?
|
tetracyclines; aminoglycosides; aminocyclitols
|
|
|
What is the MOA of Chloroamphenicol?
|
INHIBITS TRANSPEPTIDATION catalyzed by peptidyl transferase; peptide and donor site cannot be transferred.
|
|
|
Chloroamphenicol acts on the 50S or 30S subunit?
|
50S
|
|
|
Is Chloramphenicol bacteriostatic or bactericidal?
|
Bacteriostatic.
|
|
|
What is important about the metabolism of chloramphenicol?
|
It is metabolized and inactivated by HEPATIC GLUCURONOSYL TRANSFERASE.
|
|
|
Why isn't chloramphenicol used very much?
|
It's toxicity limits its use.
-no longer used US as broad spectrum agent -still widely used internationally |
|
|
What clinical condition does chloramphenicol cause in babies?
|
Grey Baby Syndrome.
|
|
|
What are the clinical uses for chloramphenicol?
|
Meningitis (N. meningitidis--meningoccal; Pneumococcal; H. influenzae) in beta lactam sensitive patients.
|
|
|
What are the Tetracyclines?
|
Tetracylcine, Doxycycline, demeclocycline, minocycline.
|
|
|
What is the MOA of the tetracyclines?
|
Bind to 30S subunit at a site that BLOCKS THE BINDING OF THE AMINO ACID CHARGED tRNA to the acceptor site.
|
|
|
Tetracyclines act on the 50S or 30S subunit?
|
30S subunit.
|
|
|
What affects the absorption of tetracyclines?
|
Food.
|
|
|
**Which tetracycline is the best choice for a patient with decreased renal function?**
|
Doxycycline.
|
|
|
Where are the tetracyclines metabolized?
|
Liver.
|
|
|
What kind of toxicity do you worry about with tetracyclines?
|
HEPATOXICITY! (esp. minocycline)
|
|
|
As a doctor, how would you decrease the number of toxic events associated with tetracycline use?
|
I would not use tetracyclines during pregancy, for children under the age of 8, and I would always discard unused tetracyclines.
|
|
|
Are tetracyclines bacteriostatic or bactericidal?
|
bacteriostatic
|
|
|
Tetracyclines are indicated for?
|
Mycoplasma pneumonia (but macrolides are used more); chlamydia; Rickettsia
|
|
|
Tetracycline is use for?
|
GI ulcers caused by H. pylori.
|
|
|
Doxycyline is used for?
|
Lyme Disease.
|
|
|
Tigecycline is structurally related to?
|
the tetracyclines
|
|
|
Tigecycline is indicated for?
|
MRSA; complicated intra-abdominal infections; complicated skin & skin structure infections.
|
|
|
Tigecycline is empiric therapy for?
|
severe infections
|
|
|
Does tigacycline require dosage adjustment for renal dysfunction?
|
NO.
|
|
|
How is tigacycline administered?
|
injection only.
|
|
|
What drugs are Macrolides?
|
Erythromycin, Azithromycin, Clarithromycin.
|
|
|
What is the MOA of Macrolides?
|
BLOCK TRANSLOCATION by reversible binding to 50S subunit; block formation of initiation complex.
*same MOA as Lincosamides (Clindamycin)! |
|
|
Are macrolides bacteriostatic or bactericidal?
|
Bacteriostatic
|
|
|
Do macrolides have good oral availability?
|
Yes.
|
|
|
Which of the macrolides inhibit the P450 enzyme?
|
erythromycin & clarithromycin
|
|
|
Which of the macrolides does NOT inhibit the P450 enzyme?
|
Azithromycin
|
|
|
Because erythromycin & clarithromycin inhibit the P450 enzyme which antibiotic would you not use them with?
|
Clindamycin
|
|
|
As a result of their inhibition of the P450 enzyme, erythromycin and clarithromycin are toxic to this organ?
|
Liver-->HEPATOTOXIC
|
|
|
What are the clinical uses of the macrolides?
|
MYCOPLASMA PNEUMONIAE (preferred to tetracyclines); Legionnaires; Chlamydia (azithromycine as an alternative to doxycycline for pregnant women)
|
|
|
What is a common feature amongst the bacteria that the macrolides are used to treat?
|
They have little or no cell wall!
|
|
|
Which macrolide would you use for treatment of Chlamydia?
|
Azithromycin
|
|
|
What is the the only drug classified as a Streptogramin?
|
Quinupristin-dalfopristin
|
|
|
What is the MOA of quinupristin-dalfopristan?
|
Constricts the exit channel through which the nascent peptides are extruded.
*50S |
|
|
Which ribosomal subunit does quinupristin-dalfopristin act on?
|
50S
|
|
|
Is quinupristin-dalfopristin available IV or orally?
|
IV only
|
|
|
Is quinupristin-dalfopristin bacteriostatic or bactericidal?
|
Bactericidal
|
|
|
quinupristin-dalfopristin is a potent inhibitor of which group of enzymes?
|
CYP3A4 enzymes
|
|
|
What is the clinical use for quinupristin-dalfopristin?
|
Reserved for treating organisms resistant to other drugs:
-Vancomycin resistant Enterococcous faecium -complicated skin/skin structure infections (MSSA) |
|
|
What is the only drug in the Oxazolidinone group?
|
Linezolid
|
|
|
What is the MOA of Linezolid
|
INHIBITS INITIATION of protein synthesis-->prevents formation of the 70S complex by binding the 50S subunit.
|
|
|
Which ribosomal subunit does Linezolid act on?
|
50S.
|
|
|
Is Linezolid Bacteriostatic or Bactericidal?
|
BOTH!!
-Bacteriostatic against Enterococci and staphylococci (*Vanco resistant E. Faecium) -Bactericidal against Streptococci |
|
|
What are the clinical uses of Linezolid?
|
-many gram-positive cocci (poor gram-neg coverage)
-reserved for treating resistant organisms -enterococci and staph (especially vanco resistant E. faecium) (bacteriostatic) -Streptococci (bactericidal) |
|
|
What kind of drug interactions can you expect with Macrolide antibiotics?
|
Expect drug interactions with other P450 metabolized drugs!!!
|
|
|
Clindamycin (a lincosamide) is used for prophylaxis of what condition?
|
Prophylaxis of endocarditis in valve disease patients who are penicillin allergic.
|
|
|
What is the Post Antibiotic Effect (PAE)?
|
Persistent suppression of bacterial growth after limited exposure to an antimicrobial agent.
|
|
|
What is the potential result of quinupristin-dalforpristin (Streptogramins) inhibiting the CYP3A4 enzymes?
|
IMPORTANT: plasma levels of the other drugs metabolized by CYP3A4 could INCREASE.
|
|
|
Linezolid is Not a substrate or inhibitor of which enzymes?
|
Not a substrate OR inhibitor of P450 enzymes!
|
|
|
Is linezolid absorbed better PO or IV?
|
BOTH! Well absorbed either PO or IV!
|
|
|
What drugs make up the Aminoglycosides?
|
Gentamycin, Streptomycin, Amikacin, and Tobramycin.
|
|
|
What is the MOA of the aminoglycosides?
|
MOA of aminoglycosides:
1-Blocks initiation complex formation 2-Causes misreading of the mRNA complex formation 3-Inhibits translocation |
|
|
Which ribosomal subunit does the aminogylcosides act on?
|
30S
|
|
|
Do aminoglycosides exhibit a post-antibiotic effect?
|
Yes.
|
|
|
In what situation would you adjust the dosage of an aminoglycoside and why?
|
In patients with DECREASED RENAL FUNCTION because glomerular filtration is major route of elimination.
|
|
|
Are aminoglycosides bacteriostatic or bactericidal?
|
Bacteriocidal.
|
|
|
With what class of antibiotics do aminoglyosides have synoergy with?
|
Beta Lactams
|
|
|
Do aminoglycosides have good or poor oral absorption?
|
Poor.
|
|
|
What effect does the poor oral absorption of aminoglycosides have on their useage?
|
They are used orally to treat GI infections just like Vancomycin is.
|
|
|
What are the aminoglycosides used for clinically?
|
serious AEROBIC gram-NEGATIVE infections:
-E. coli -Enterobacter -Klebsiella -Proteus -Pseudomonas |
|
|
What is streptomycin used for?
|
TB
|
|
|
Do aminoglycosides exhibit concentration dependent killing?
|
YES.
|
|
|
What is the only drug classified as an Aminocyclitol?
**NOT CURRENTLY IN CLINICAL USE |
Spectinomycin
|
|
|
What ribosomal subunit does spectinomycin (an aminocyclitol) act on?
**NOT CURRENTLY IN CLINICAL USE |
30S
|
|
|
What is spectinomycin used for?
**NOT CURRENTLY IN CLINICAL USE |
Alternative therapy for gonorrhea in penicillin, beta lactam or quinolone allergic patients or for resistant gonococci.
|
|
|
What is the only Cyclic Lipopeptide?
|
Daptomycin
|
|
|
What is the MOA of Daptomycin?
|
depolarized the bacterial cell membrane-->loss of membrane potential-->pottassium efflux-->cell death
|
|
|
Do not use Daptomycin for the treatment of?
|
Pneumonia
|
|
|
Daptomycin is bacteriostatic or bactericidal?
|
bactericidal
|
|
|
What is the clinical use of daptomycin?
|
complicated skin and skin structure infections caused by susceptible Gram-POSITIVE organisms (including MRSA)
|
|
|
Is daptomycin available IV or orally?
|
IV
|
