Antibiotics (17) Flashcards Preview

SP18: Pharm Final > Antibiotics (17) > Flashcards

Flashcards in Antibiotics (17) Deck (86):
1

Why is penicillin G not a good drug?

Not stable in stomach pH

Pen V instead

2

What are the properties of ideal antibacterials?

1. Stable in body
2. Water soluble
3. Diffusible across junctions
4. Slow excretion
5. Large therapuetic index

3

What could cause sulfonamides to cause crystalluria?

Lack of hydration

4

_________ has an effect on the choice of drug, how much drug, and drug combinations.

Resistance

5

What are the two ways in which microbes will respond to drugs?

1. Resistance
2. Secondary products of bacterial destruction (esp gram -)

6

T/F: Vancomycin is strictly a bactericidal drug.

False

Bactericidal mechanism, but due to resistance has become functionally static

7

T/F: Gram positive bacteria have a thick cell wall.

True

8

T/F: Gram positive bacteria stain dark purple.

True

Thick dark cell wall

9

T/F: Vancomycin is effective on both gram- and gram+ bacteria.

False

Only gram+

Cannot get through pores of gram-

10

T/F: Resistance of gram- bacteria to ciprofloxacin is an intrinsic method of resistance.

False

Pores are changed so it cannot enter - acquired resistance

11

T/F: Resistance of gram- bacteria to vancomycin is an intrinsic method of resistance.

True

Pores are naturally too small

12

T/F: The gold standard of testing antibiotic activity is the broth dilution assay.

True

13

T/F: MIC values increase as resistance increases.

True

14

How do penicillin and aminoglycosides use synergism to fight bacteria?

Penicillin breaks cell wall, Aminoglycoside gets in cell and does damage

15

T/F: Sulfonamids and penicillins work well together.

False

Sulfonamids stop cell from growing -> penicillin cannot work

16

T/F: Sulfonamides are bacteriocidal.

False

Bacteriostatic - stop cell growth

17

Sulfonamides act as competitive inhibitors for which enzyme?

Dihydropteroate synthase

Result is inhibition of folate (and DNA) synthesis

18

What is the spectrum for sulfonamides?

Gram+ and gram- but relatively narrow

19

What is the mechanism of resistance to sulfonamides?

targeted enzyme is altered to avoid drug

20

What are three clinical uses for sulfonamides?

1. UTI
2. P. jiroveccii in HIV/AIDS
3. Prophylaxis (burns, wounds)

21

T/F: Sulfonamides are safe for new borns (neonates).

False

Can cause kernicterus

22

What drug other than sulfonamides alters folic acid production?

Trimethoprim

Alters dihydrofolate reductase

23

T/F: Trimethoprim works downstream from sulfonamides in the production of folic acids.

True

24

T/F: Trimethoprim has a broader spectrum than sulfonamides.

True

25

What is the mechanism of resistance to trimethoprim?

More enzyme is produced

26

Trimethoprim is commonly combined with what other drug?

Sulfamethoxazole

Becomes bactericidal

27

T/F: Combo of trimethoprim and sulfamethoxazole is useful in treating MRSA and SSTIs.

True

28

T/F: Trimethoprim is extremely effective against P. aeruginosa.

False

Low MIC for many pathogens

Ineffective for P. aeruginosa

29

What is the first line for tuberculosis?

Rifampin

30

T/F: Rifampin is bactericidal.

True

31

What enzyme is inhibited by rifampin?

RNA polymerase

32

What is the resistance mechanism for rifampin?

altered binding to RNA polymerase

33

Why would you not give rifampin to a patient with HIV/AIDS?

Will induce p450 de-acetylation of other drugs

Give Rifabutin instead

34

What is the mechanism of quinolones?

DAMAGE DNA

inhibit DNA gyrase and DNA topoisomerase IV

35

T/F: Quinolones are bacteristatic.

False

Cidal

36

What is the spectrum of quinolones?

Gram -/+

37

Which quinolones are anti-pseudomonal?

Cipro and levofloxacin

38

T/F: Quinolones are second line of defense for tuberculosis.

True

Rifampin is first

39

Which antibiotic is used to treat anthrax?

Ciprofloxacin (quinolone)

40

What are the mechanisms of resistance to quinolones?

1. Mutated enzymes
2. Efflux of enzymes
3. Altered porins in cells

41

T/F: Quinolones can cause tendon ruptures and peripheral neuropathy

True

42

What is special about the third and fourth classes of quinolones?

Levofloxacin and moxifloxacin

Good against gram +/- (class 1 and 2 only gam-)

43

What drugs should be used to target respiratory bacteria (S. pneumoniae) that are resistant to penicillin?

3rd and 4th generation quinolones (levo and moxifloxacin)

44

T/F: Levofloxacin is not cleared by the kidney and is low in the urine.

False

Moxifloxacin

45

_________ is primarily used for treating anaerobic bacteria.

Metronidazole

46

What is the mechanism of action of metronidazole?

Reduced to metabolites that will alter DNA function

Bactericidal

47

What is the mechanism of resistance to metronidazole?

Drug will not be reduced to metabolites

48

What are some toxic effects of metronidazole?

1. Metalic taste
2. Nausea and vomiting (disulfiram effect)
3. Central neurotoxicity

49

What will be the negative effect of drinking alcohol with metronidazole?

Disulfiram effect will result in vomiting/nausea

50

*Which type of bacteria will not be effected by cell wall inhibitors?

Mycoplasma

51

How does cycloserine inhibit cell wall synthesis?

Inhibits L-ala -> D-ala

52

How does vancomycin inhibit cell wall synthesis?

Inhibits peptidoglycan synthase

53

What are four cell wall inhibitors?

1. Bacitracin
2. Cycloserine
3. Fosfomycin (UTIs)
4. Vancomycin

54

How will the cells eventually die from cell wall inhibitors?

Cell wall will not keep growing, pressure in cell will build up -> osmotic lysis

55

T/F: Penicillins will normally cross the BBB?

False

Will during meningitis because cells are inflamed

56

How do penecillins work?

They mimic D-ala-D-ala, so penicillin binding proteins bind penicillin instead of the proper amino acids -> disrupt cell wall crosslinking

57

What is Beta-lactamase?

A resistance factor to penicillin

Will cleave beta-lactan ring turning penicillin into benzylpenicilloic acid

58

Which two drugs damage the cell membranes of bacteria?

Polymyxins and Daptomycin

59

Which cell membrane damaging drug has a rapid action and is concentration dependent?

Daptomycin

60

*T/F: Polymyxins are effective against Gram+ only.

False

Polymyxens = gram-

Daptomycin = gram+

61

Which drug can be used against multi-drug resistant pseudomonal infections via IV?

Polymyxins

Esp against Acinetobacter

62

T/F: Resistance to polymyxins is very common.

False

63

T/F: Daptomycin is often used to treat lung infections.

False

It will inactivate surfactant

64

T/F: Daptomycin will have a post antibiotic effect.

True

65

What are the four major mechanisms of resistance to Beta-Lactams (penecillin)?

1. Beta-lactamases
2. Altered PBPs (MRSA)
3. Altered porins (gram-)
4. Increased efflux (gram-)

66

T/F: The majority of protein synthesis inhibitors are bacteriostatic.

True

Aminoglycosides are cidal

67

T/F: Drugs used to inhibit bacterial protein synthesis will bind to 40s and 60s subunits.

False

50s (most) and 30s (tetracyclines)

68

T/F: Aminoglycosides are mainly effective against gram- bacteria.

True

69

What is the major resistance mechanism for aminoglycosides?

Transferase enzymes in bacteria change the drugs structure

70

Which drug is often used against endocarditis?

Aminoglycosides

Mostly gram-, some gram+

71

T/F: Kanamycin is a commonly used aminoglycoside.

False

It has developed resistance so others are used

72

T/F: Aminoglycosides are concentration-dependent drugs with post-antibiotic effects.

True

73

What four drugs are concentration-dependent and will therefore have post-Antibiotic effects?

1. Aminoglycosides
2. Quinolones
3. Daptomycin
4. Metronidazole

74

What three drugs are time-dependent?

1. Beta lactams
2. Vancomycin
3. Quinolones

75

T/F: Many beta-lactams will begin with Cep- or Ceph-.

True

76

Which types of drugs end in -floxacin?

Quinolones

77

Cell wall inhibitors would not work against mycoplasma. What agent would be effective?

Tetracyclines

78

T/F: Tetracyclines have a broad spectrum.

True

79

Gray baby syndrome is due to high concentrations of which drug?

Chloamphenicol

80

What is the prototype macrolide?

Ezythromycin

81

T/F: Macrolides are bactericidal.

False

static

82

What types of infection are most often fought with macrolides (erythromycin)?

Respiratory infections (C. pneumoniae)

83

T/F: Ketolides (telithromycin) is a commonly used drug.

False

Liver toxicity

84

_________ is a protein synthesis inhibitor often used for anaerobic infection of penecillin resistant bacteria.

Clindomycin

85

What is a negative of Clindomycin?

Can become susceptible to C. dif -> Pseudomembranous colitis

86

T/F: Taken alone, Linezolid is effective against vanco resistant bacteria and MRSA.

True

Linezolid (static) alone

Quinupristin/dalfopristin (cidal) together