Antibacterials Flashcards Preview

Pharmacology Block 3 > Antibacterials > Flashcards

Flashcards in Antibacterials Deck (77):
1

B-lactams MOA:

Inhibit PBPs, which catalyze cell wall crosslinks. Competitive and irreversible.

2

B-lactams MOR:

1. B-lactamase (most prevalent).
2. Altered PBP (MRSA).

3

B-lactams SEs:

Allergic reactions: Anaphylaxis, rash.
Diarrhea, enterocolitis.
Seizures (rare).

4

Penicillin G and V:

-GM+ anaerobes (B-lactamase negative Strep).
-Syphilis
-Neisseria meningitidis (behind Ceftriaxone).

5

Oxacillin:

-B-lactamase-producing staphylococci.
-MSSA

6

Amoxicillin:

-B-lactamase-negative GM+ (Streptococcus, listeria).
-GM- (Haemophilus)
-First-line treatment for otitis media.

7

Ampicillin:

-Same as amoxicillin, plus treats meningitis (Neisseria, Listeria), GI infections.

8

Ticarcillin:

-Broad GM- effectiveness, including pseudomonas aeruginosa.
-Often used with a B-lactamase inhibitor to hit anaerobes.

9

Piperacillin:

-Broad GM- effectiveness, including pseudomonas and klebsiella (ticarcillin-resistant)
-Often used with a B-lactamase inhibitor.

10

2 B-lactamase inhibitors:

1. Clavulanic acid.
2. Tazobactam

11

Cephalosporins spectrum of activity:

1st generation: best for GM+
2nd generation: more GM- activity.
3rd generation: best for GM -

12

Cefazolin:

-1G
-GM+
-Surgical prophylaxis against skin flora.

13

Cephalexin:

-1G
-Oral form of Cefazolin.

14

Cefuroxime:

-Only 2nd gen to penetrate CSF.
-Best of 2nd gen against Haemophilus.

15

Cefoxitin:

-2G
-Cefuroxime plus added benefits against anaerobes such as Bacteroides.

16

Ceftriaxone:

-3G
-1st line against gonorrhea, meningitis (Neisseria).

17

Ceftazidime:

-3G
-Active against Pseudomonas.

18

Cefepime:

-4G
-Similar spectrum to Ceftazidime, except more resistant to type I B-lactamases.
-Empirical treatment of serious inpatient infections.

19

Imipenem use and side effects:

-Broad-spectrum.
-Resistant to many B-lactamases, including ESBLs.
-Not effective against MRSA.
-Give with cilastatin, a renal peptidase inhibitor.
-Use if mixed or ill-defined infection, those not responsive to other drugs.
Side effects: Hypersensitivity, seizures, dizziness, confusion, GI effects.

20

Aztreonam:

-Used against GM- aerobic rods.
-Resistant to many B-lactamases.
-Can be used in those with known hypersensitivities to penicillins.
Side effects: seizures, GI effects, anaphylaxis, transient EKG changes.

21

Vancomycin MOA:

MOA: Inhibits cell-wall synthesis: by interfering with cross-linking and elongation of the peptidoglycan chains.

22

Vancomycin uses:

GM+ ONLY.
-First line against HA-MRSA.
-Severe C diff infections (behind metronidazole).

23

Vancomycin SEs:

-“Red neck” syndrome.
-Nephrotoxicity.
-Phlebitis.
-Ototoxicity.

24

Fosfomycin MOA:

Inactivates enolpyruvyl transferase, an early stage cell wall synthesis enzyme.

25

Fosfomycin uses:

-Uncomplicated UTIs caused by E. coli, enterococcus.

26

Bacitracin MOA:

Interferes with lipid carrier that exports early cell wall components through the cell membrane.

27

Bacitracin uses:

Topical agent against GM+

28

Polymyxins MOA:

Cationic detergents that bind LPS in the outer membrane of GM-

29

Polymyxin B:

Topical agent against GM-, pseudomonas.

30

Daptomycin MOA:

Binds to bacterial cytoplasmic membrane, causing rapid membrane depolarization.

31

Daptomycin uses:

-Complicated skin infections (Staph. Aureus, streptococcus, enterococcus).

32

Quinolones MOA & MOR:

MOA: Inhibits bacterial DNA gyrase, thus interfering with replication and repair.

MOR: 1. Altered DNA gyrase.
2. Decreased permeability.
3. Combo of the two.

33

Quinolones misc:

AUC killers.

34

Quinolones SEs and contraindications:

-Contraindicated in those with seizure disorders, pregnancy, children.
-EKG irregularities.
-Athropathy, tendon rupture.

35

Name the quinolones:

1. Norfloxacin
2. Ciprofloxacin
3. Moxifloxacin

36

Norfloxacin:

UTIs (achieve therapeutic concentrations only in the UG region).

37

Ciprofloxacin:

UTIs, infectious diarrhea, skin infections, bone and joint infections, chlamydia.

38

Moxifloxacin:

-Better GM+ spectrum than most quinolones.
-Respiratory infections (NOT strep throat).
-CA pneumonia, bacterial bronchitis.

39

Nitrofurantoin MOA, use, SEs:

MOA: Nitroreductase enzyme converts drug to reactive compounds which can damage DNA.

Use: Lower UTIs.

SEs: -Peripheral neuropathy.
-Pulmonary fibrosis in elderly.
-GI upset.

40

Rifampin MOA:

Inhibitor of RNAP, thereby inhibiting RNA synthesis.

41

Rifampin uses:

-Primarily for treatment of pulmonary TB.
-Prophylaxis of meningococcal meningitis, haemophilus influenza.
-Part of combination therapy for leprosy.

42

Rifampin SEs:

-Orange urine, tears, sweat.
-Strongly induces CYP3A.

43

Fidaxomicin uses:

-3rd line for C diff (behind metronidazole, vancomycin).
-Only hits clostridium, so useful for allowing patient to restore normal gut flora.
-Less recurrence of C diff than vanco and metronidazole.

44

Fidaxomicin MOA:

Inhibitor of RNAP, thereby inhibiting RNA synthesis.

45

Metronidazole uses:

-C diff enterocolitis.
-Combination therapy for H. pylori.
-Gardnerella vaginalis.

46

Metronidazole MOA:

Anaerobes reduce the nitro group, resulting product disrupts DNA.

47

Metronidazole SEs:

-Long-term treatment: leukopenia, neutropenia.
-Bacterial and fungal superinfections (Candida).

48

Aminoglycosides MOA:

Transported into bacteria by an energy-requiring aerobic process. Binds to several ribosomal sites, stopping initiation, causes premature release of ribosome from mRNA, and mRNA misreading.

49

Aminoglycosides uses:

-More effective against GM- than GM+, but when using against GM+, use with quinolone or cell wall inhibitor.
-Use only against serious infections because of toxicity.

50

Aminoglycosides misc:

-Concentration-dependent killing.
--Post-antibiotic effect: sustained activity for several hours after aminoglycoside concentration has dropped below effective levels. Allows for less frequent dosing.
--Do not mix B-lactams with aminoglycosides in vitro – will inactivate the drug.

51

Name the aminoglycosides:

1. Gentamicin
2. Tobramicin
3. Amikacin (most broad spec)

52

Name the tetracyclines:

1. Minocycline
2. Doxycycline

53

Tetracyclines MOA:

Blocks protein synthesis by binding to the 30S ribosomal subunit, preventing attachment of aminoacyl-tRNA to the acceptor site.

54

Tetracyclines MOR:

1. Efflux pumps.
Cross-resistance.

55

Tetracyclines uses:

-Preferred agents for rickettsia, chlamydia, Mycoplasma, Ureaplasma, Borrelia.
-Ca++ inhibits absorption.

56

Tigecycline MOA:

Same as the tetracyclines, but binds additional sites on ribosomes.

57

Tigecycline uses:

-Used against many GM+, including MRSA.
-A few GM-, but NOT pseudomonas.

58

Chloramphenicol MOA:

Blocks protein synthesis: Inteferes with binding of aminoacyl-tRNA to 50S subunit, and inhibits peptide bond formation.

59

Chloramphenicol uses:

Broad spec – only use in serious cases.
-Alternative agent for meningitis, brain abscesses.

60

Chloramphenicol SEs:

-Bone marrow depression, can progress to a fatal aplastic anemia.
-Grey baby syndrome.
-Optic neuritis.

61

Macrolides MOA:

Block protein synthesis by binding to the 50S ribosomal subunit, blocking the translocation step.

62

Macrolides SEs:

-Increases risk of arrhythmias and cardiac arrest (QT prolongation).

63

Erythromycin uses:

-Enhances GI motility.
-Primarily against GM+ (Staph and Strep)
-Also against Chlamydia, mycoplasma, bordetella, campylobacter.
-Interferes with CYP3A metabolism of other drugs.

64

Clarithromycin:

-Better kinetics than erythromycin (less frequent dosing).
-Less GI motility.
-Somewhat wider spectrum.
-Uses are same as erythromycin
-Also part of combination therapy for H pylori.
-Also used for MAC treatment, prophylaxis.

65

Azithromycin:

-Respiratory infections.
- Gonorrhea (ceftriaxone + azithromycin or doxycycline).

66

Clindamycin MOA:

Same as macrolides, but not a macrolide.

67

Clindamycin uses:

-Inhibits most GM+ cocci, and many anaerobes, incl. Bacteroides fragilis.
-Suppresses bacterial toxin production (Strep and Staph).

68

Linezolid MOA:

Blocks protein synthesis by binding to the 50S ribosomal subunit, interfering with the formation of 70S initiation complex.

69

Linezolid uses:

-1st line against CA-MRSA.
-VRE
-Staph
-Strep

70

Linezolid SEs:

-Bone marrow depression.
-Non-selective inhibitor of MAO (avoid foods with tyramine).

71

Sulfonamides MOA:

Inhibit folate synthesis in bacteria by competitive inhibition of dihydropteroate synthase.

72

Sulfonamides SEs:

-Renal damage from crystalluria.
-Inhibit CYP2C9 – potentiates action of other drugs (Warfarin).

73

TMP/SMX:

UTIs, bacillary dysentery, typhoid fever.

74

Silver sulfadiazine:

Use on burn wounds.

75

Trimethoprim uses:

Given in conjunction with sulfamethoxazole – combined effects are bactericidal.
Used for UTIs, URIs and otitis media.
-Also for Pneumocystis jiroveci.

76

Trimethoprim MOA:

Inhibit folate synthesis in bacteria by competitively inhibiting dihydrofolate reductase.

77

Trimethoprim SEs:

Bone marrow suppression.