EXAM #4: ANTIBIOTICS II Flashcards Preview

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Flashcards in EXAM #4: ANTIBIOTICS II Deck (67):
1

Describe the composition of peptidoglycan.

Peptidoglycan is composed of repeating monomers of NAM-NAG-pentapeptide

2

What is NAM?

N-acetylmuramic acid

3

What is NAG?

N-acetylglucosamine

4

What is the function of the Penicillin-Binding Proteins?

Forming peptidoglycan by creating the NAM-NAG bonds

5

What category of antibiotics inhibit the PBPs?

Beta-Lacam antibiotics

6

What drugs are part of the B-Lactam family of antibiotics?

Penecillin
Cephalosporins
Monobactams
Carbapenems

7

Are the B-Lactams bacteriostatic or bactericidal?

Bactericidal

8

What enzyme can cause drug resistance in the B-Lactams?

Beta-Lactamase, which hydrolyzes the Lactam ring that is integral to this class of antibiotics

9

List the antibiotics that fall into the PCN family.

PCN G
PCN V
Amoxicillin
Methicillin
Nafcillin
Oxacillin
Ampicillin
Piperacillin
Ticarcillin
Azlocillin

****All end in "cillin"*****

10

What are the key adverse effects seen with the PCN family of antibiotics?

Hypersensitivity

11

If a patient has a severe reaction to a PCN-type antibiotic, what should you be concerned about?

Hypersensitivity to ALL Beta-Lactam drugs, not JUST the PCNs

12

What is unique about the drug Methicillin?

This is a synthetic PCN-type drug that is RESISTANT to Beta-Lactamase

13

What PCN-type drugs are narrow spectrum?

PCN G
PCN V
Methicillin*
Nafcillin*
Oxacillin*

*Note that all three are "v. narrow spectrum" and are ALL resistant to Beta-Lactamase

14

What PCN-type drugs are broad spectrum?

Ampicillin
Amoxicillin
Piperacillin
Ticarcillin
Azlocillin

15

What is the utility of Beta-Lactamase inhibitors?

- Side-setting drug resistance mechansim
- These drugs can be CO-ADMINISTERED with PCN-type drugs

16

What is the hallmark Beta-Lactamase inhibitor?

Clavulanic acid

17

How is Clavulinc acid commonly administered?

Co-administration with Amoxicillin as AUGMENTIN

18

If a patient has a mild hypersensitivity reaction to PCN-type drugs, what family of drugs should you consider?

Cephalosporins

19

Generally, how do the Cephalosporins differ from the PCN-type drugs?

More resistant to Beta-Lactamase

20

What is the key adverse reaction to the Cephalosporins?

Hypersensitivity

21

What is the theme in terms of specificity/generation in the Cephalosporins?

- There are 4 generations - 1 is narrow (gram positive only)
- 4 is the broadest (gram positive and negative)

22

What is the theme in Cephalosporin generations and CNS penetration?

3rd and 4th generation Cephalosporins penetrate the BBB

23

What are the first generation Cephalosporins?

Cefazolin

24

What are the 2nd generations cephalosporins?

Cefotetan
Cefaclor
Cefuroxime

25

What are the 3rd generation Cephalosporins?

Ceftriaxone
Cefotaxime
Cefdinir
Cefixime

26

What is the 4th generation Cephalosporin?

Cefepime

27

What is the MOA of the monobactams?

PBP inhibitor

28

What is the only drug in the monobactam family?

Aztreonam

29

What are the important features to remember about Aztreonam?

- Gram negative ONLY
- Penetrates the BBB
- Beta-lactamase resistance

30

What is the key adverse effect seen with Aztreonam?

Mild hypersensitivity

31

What is the MOA of the Carbapenems?

PBP inhibitors

32

What is the spectrum of activity in the Carbapenems?

Both gram negative and positive

33

Generally, when are the Carbapenems used?

Life-threatening infections

34

What are the unique features of the Carbapenems?

- Resistant to Beta-Lactamase
- Susceptible to Carbamenemase

35

List the drugs that fall into the Carbapenem family.

Doripenem
Imipenen
Entapenem
Meropenem

36

What are the key side effects seen with the Carbapenems?

GI disturbances

37

What family of antibiotics does Vancomycin fall into?

Glycopeptide antibiotic

38

What is the MOA of Vancomycin?

- Prevents elongation of the peptidoglycan cell wall
- Binds to the pentapeptide and sterically inhibits pentapeptide linkage
- Specific target is the D-ala/ D-ala

****Note it is NOT binding to the PBP but IS still a Beta-Lactam antibiotic

39

What is Vancomycin commonly used to treat?

Gram + bacteria e.g. MRSA

40

What should you remember about Vancomycin and the CNS?

- Poor CNS penetration
- However, still a good first choice to treat meningitis

41

What is the key adverse effect seen with Vancomycin?

Red Man Syndrome
- Flushing
- Red neck

42

What is the MOA of Bacitracin?

Blocks incorporation of amino acids and nucleic acids into the cell wall of the bacteria

*****Inhibits the building of the building blocks that are used to create the cell wall*****

43

What is the specificity of Bacitracin?

Both gram positive and negative

44

What is unique about Bacitrain?

Commonly included in TOPICAL preparations (OTC)

45

What type of drug is Fosfomycin?

Cell wall synthesis inhibitor

*Similar to Bacitracin*

46

What is the specific MOA of Fosfomycin?

Prevents the synthesis of UDP-NAM--disaccharide (a component of peptidoglycan)

47

What is Fosfomycin commonly used to treat?

UTIs

48

What is the general MOA of protein synthesis inhibitor antibiotics?

Bind and inhibit the bacterial ribosome--70S

49

In general, are the protein synthesis inhibitors bactericidal or bacteriostatic?

Bacteriostatic

50

What are the two subunits of the bacterial ribosome?

50S and 30S

51

Review the steps of protein synthesis.

1) charged tRNA binds to the A site of the ribosome
2) Peptide bond formation between amino acid in A site and growing chain
3) Newly uncharged tRNA exits
4) Longer amino acid chain translocates into the P site

52

What class of antibiotics are the Aminoglycosides?

Protein synthesis inhibitors

53

List the aminoglycosides?

Streptomycin
Gentamicin
Kanamycin
Amikacin
Tobramycin
Neomycin

54

How are aminoglycoside antibiotics commonly used?

In combination with Beta-Lactams for SERIOUS gram negative infections

55

What part of the bacterial ribosome is inhibited by the aminoglyocisdes?

30S subunit by preventing the tRNA molecules from entering the A site

56

What are the key adverse effects associated with the Aminoglycosides?

1) Nephrotoxicity
2) Ototoxicity

57

How do the Aminoglycosides differ from the general pattern of the protein synthesis inhibitors?

Generally BACTERICIDAL

58

What antibiotic class are the Macrolides?

Protein synthesis inhibitors

59

List the Macrolides.

Erythromycin
Clarithromycin
Azithromycin

60

What is the target of the Macrolides?

50S subunit--disrupts the translocation of the growing amino acid chain from the A site to the P site to allow for a new amino acid to enter

61

What are the key side effects associated with the Macrolides?

GI disturbances

62

How do the Macrolides alter GI physiology?

Motilin receptor agonists

63

What class of antibiotic are the Tetracyclines?

Protein synthesis inhibitors

64

What subunit of the bacterial ribosome do the Tetracycline block?

30S

65

What is the specific MOA of the Tetracyclines?

The drug blocks the A site of the ribosome to prevent the charged tRNA from entering

66

What nutrient interaction do you need to remember about the Tetracyclines?

- Binds Ca++
- Will result in GROWTH of calcified tissue

*Don't use in growing kids or pregnant women

67

What are two additional adverse effects that need to be remembered about the Tetracyclines?

1) Disrupt the normal flora (more than the other drugs)
2) Cause photosensitivity

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