Kumar's Final Review - Anti-Microbials - AH Flashcards Preview

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Flashcards in Kumar's Final Review - Anti-Microbials - AH Deck (93):
1

Name the 5 major categories of Antimicrobials based on MOA

1. Folic Acid synthesis inhibitors, 2. Beta-lactam antibiotics, 3. Protein Synthesis inhibitors (30s/50s) 4. Nucleic acid synthesis inhibitors, 5. Misc. (cell wall, nucleic acid synthesis 20s, cell membrane)

2

Sulfonamides MOA?

PABA analoge: Inhibit folic acid synthesis by irreversibly blocking dihydroperoic acid

3

Metabolism for Sulfonamides?

metabolized in liver (also in lungs). Acetylation = major pathway (poor in dogs)

4

*What happens as a result of poor acetylation of sulfunamides in dogs?

*Urine precipitates = crystalluria (Tx by alkalizing the urine)

5

Which class of sulfonamides exerts local action on the GIT?

Enteric sulfonamides (not absorbed in the GIT)

6

What are some examples of enteric sulfonamides and what are they used for?

Sulfasalazine – colitis in dogs. Sulfaquinoxaline – coccidiosis in chickens. Sulfacetamide – eye (neutral pH)

7

What are the topical sulfonamides?

Silver sulfadiazine and Mafenide

8

Sulfonamide breed sensitivities ?

Dobermans → polyarthritis, fever, cutaneous eruptions, hepatitis. Duck&Dog → hypoglycemia (decreased thyroid hormone production)

9

What are potentiated sulfonamides?

Combination of sulfonamide and diaminopyrimidine

10

What is the spectrum for potentiated sulfonamides?

Broad spectrum, bacteriaCIDAL – synergisism between sulfonamides and diaminopyrimidine

11

Prep of potentiated sulfonamides has what ratio?

Sulfamethoxazole + Trimethoprim (5:1)

12

Side effect of potentiated sulfonamides in dogs?

Reversible hypothyroidism

13

Sulfonamide Immunological SE?

Heptaic necrosis, Keratoconjumctivitis Sicca

14

List 3 Diaminopyrimidines and how they are used

Primethamine – protozoa. Trimethoprim – used with sulfonamides (5 sulfa:1 trimeth). Ormethoprim – ruminants

15

Major categories of Beta-lactam antibiotics?

Penicillin, Chephalosporin, Carbapenems, Monobactam

16

Beta-lactam MOA?

Inhibits cell wall synthesis via penicillin binding protein interference – bactericidal action

17

What are the natural Penicillins?

Penicillin V/G

18

How is Penicillin V administered?

Oral (acid stable)

19

Penicillin G drugs

Benzathine and Procaine

20

How is procaine and procaine formulations administered?

Only by parenteral route, no IV (procaine → IM)

21

What is the admin route that prolongs Benzathine action?

Reposatory prep. Lasts for 7days

22

SE of Procaine?

Anaphylaxis and CNS in guinea pigs and chinchillas. Excitement in horses.

23

List the Semi-Synthetic Penicillins with good oral absorption

Oxacillin Cloxacillin and DicIoxacillin (all are acid stable)

24

List the semi-synthetic B-lactamase sensitive Penicillins

Amoxicillin and Ampicillin

25

Which B-lactamase sensitive drug is more orally bio-available?

Amoxicillin

26

Which B-lactamase sensitive drug is a prodrug?

Ampicillin

27

Spectrum of action for extended spectrum penicillins?

Anti-pseudomonal

28

How are extended spectrum penicillins administered?

Parenterally w/ B-lactamase inhibitors

29

List 5 ext. spec. penicillins

Azlocillin, Carbenicillin, Mezlocillin, Ticarcillin, Piperacillin

30

List the beta-lactamase inhibitors

Clavulanic acid, Sulbactam

31

Beta-lactamase inhibitor MOA?

Competative inhibitor of B-lactamase binding sites.

32

Where do cephalosporins accumulate?

in the extracellular fluid

33

What 1st generation cephalosporin is administered via parenteral route to small animals?

Cefazolin

34

Which Cephalosporin has the broadest spectrum of action, is most potent and is stable against B-lactamase?

Cefeprim

35

Other B-lactams that are not susceptible to B-lactamase enzyme degredation?

Carbapenems and Monobactams

36

What is the spectrum of Carbapenems?

Broad

37

List the 2 Carbapenems

Imipenem and Meropenem

38

Give the Monobactama drug and when it is used?

Aztreonam – used in patients allergic to penicillin

39

2 drug groups that are 30s protein synthesis inhibitors

Aminoglycosides and Tetracyclines

40

Name 3 drug groups that are 50s protein synthesis inhibitors

Macrolides, Lincosamides, Chloramphenical

41

Which of the protein synthesis inhibitors is bacteriaCIDAL? What are the rest?

Aminoglycosides are -CIDAL, the rest are -STATIC

42

What is the spectrum of action for aminoglycosides?

Narrow spectrum – kills G-ve Aerobic bacteria

43

List 2 Aminoglycosides

Amikacin: Broadest spectrum. Paromomycin: G-ve and G+ve, protozoans

44

Why is a single does of Aminoglycoside drugs efficacious?

Has biphasic penetration via concentration dependent passive diffusion via porin channels. → post antibiotic effect

45

How are aminoglycocides administered?

Parenterally – 100% BA. Not given orally due to low BA

46

Where in the body do aminoglycosides tend to bind?

Inner ear and renal cortex

47

Vd of Aminoglycosides?

Extracellular. Vd is increased in lean/ cachectic animals

48

Aminoglycoside toxicity?

Nephrotoxic to cortex (excretion without metabolism) Ototoxicity – reversible. Neuromuscular Blockade

49

Which tetracycline is best absorbed in the GIT (orally)

Doxycycline

50

Are natural Tetracyclines metabolized?

No

51

List the natural Tetracyclines

Tetracycline, Chlortetracyclin, Oxytetracycline

52

How is Oxy administered?

Oral or parenteral

53

List the semi-Synthetic Tetracyclines

Minocycline, Doxycycline

54

How is minocycline metabolized?

Oxidation

55

Where is Doxy absorbed and why?

Lipid soluble (80-90% protein binding) → large intestine → is excreted in bile

56

What animal does Doxy kill?

Fatal in horses due to alterations to GIT flora

57

Adverse reactions of Chloramphenicol?

affects mammalian ribosome → reversible BM suppression, inhibition of mammalian mitochondrial synthesis.

58

What should you never give with Chloramphenicol?

Macrolides

59

Vd of Chloramphenicol?

Wide volume of distribution: eye, CNS, heart, lung, prostate, salivary glands, liver& spleen. Crosses the placental barrier and is in milk.

60

How is Chloramphenicol metabolized?

Glucoronidation – (cats = slow)

61

Why might you go to jail for administering chloramphenicol?

If you give it to food animals

62

While Chloramphenicol in food animals will land you in jail, what derivatives can be given to FA?

Thiamphenicol or Florfenicol

63

MOA of Florfenicol?

Inhibits peptidyl transferase enzyme

64

What is florfenicol more resistant to?

Bacterial resistance

65

Microlide Drugs (5)

Erythromycin, Tylosin, Tilmicosin, Tiamulin, Azithromycin

66

What is Erythromycin used to Tx?

Campylobacter jejuni in dogs

67

Which Macrolide Is fatal to horses but can be used to Tx mycoplasma?

Tylosin

68

What Macrolide treats respiratory infections due to high conc in lung tissues?

Tilmicosin

69

What is a SE of Tilmicosin?

Cardiotoxic if given via IV

70

Tiamulin is used to treat what?

Pinkeye, Mycoplasma

71

Which microlide has PAE?

Azithromycin

72

What do you not combine with Lincosamides?

Macrolides

73

MOA of Clindamycin?

Blocks translocation process of bacterial protein synthesis

74

What is Clindamycin used to Tx?

G-ve anaerobes and T. gondii

75

SE of lincomycin?

Enterocolitis in rabbits, horses and ruminats = fatal

76

MOA of Flouroquinolones?

DNA synthesis inhibition via Topoisomerase II

77

SE of flouroquinolones in the CNS?

Excitement (GABA) – don't give to animals with seziers

78

Flouroquinolones Adverse Effects

CNS excitement via GABA → don't give to animals with seizures. Arthropathy from chelation of MG. Retinal degeneration in cats. Accumulates in phagocytic cells.

79

Flouroquinolone drug?

Enrofloxacin → Tx pyoderma, ehrlichiosis

80

MOA of metronidazole?

DNA inhibition – is reduced by oxidoreductase enzyme in mitochondria → impairs bacterial DNA structure → cidal

81

Metronidazole metabolism?

Ocidoreductase enzyme

82

Metronidazole treats what microbes?

protozoans and anaerobes

83

MOA of rifampin?

Inhibits DNA dependent RNA synthesis

84

Why do you combine Rifampin with other drugs?

Susceptible to bacterial resistance. Add other drugs to avoid resistance

85

Which Antimicrobial drugs should not be used in Food producing animals?

Chloramphenicol –> aplastic anemia. Metronidazole → carcinogenic. Nitrofuran → furazolidone carcinogenic. Vancomycin

86

What antimicrobial is a growth promoter and prophylaxis in swine?

Carabadox (suppresses aldosterone production)

87

Drug used to Tx UTI in acidic urine?

Methnamine (do not give with sulfonamides)

88

Polymyxin B MOA?

Cationic, binds to phopholipids and disrupts cell membrane

89

What is given to sterilize the bowel before surgery?

Polymyxin B. Is also a topical

90

What antimicrobials are associated with aplastic anemia?

Sulfonamides and Chloramphenicols

91

Which antimicrobials reach the CNS/Brain

Chloramphenicol, Clindamycin, Metronidazole, Pot. Sulfonamides, Cephalosporin

92

Which antimicrobials are narrow spectrum?

Beta lactams, Aminoglycosides, polymyxins

93

Which antimicrobials are bacteriostatic?

Sulfonamides, Diaminopyrimidines, tetracyclines, Chloramphenicol, Macrolides and Lincosamides