Cephalosporins Flashcards Preview

KG - Pharmacology > Cephalosporins > Flashcards

Flashcards in Cephalosporins Deck (76):
1

Name Beta-Lactams

1. penicillins
2. cephalosporins
3. monobactams
4. cardapenems

2

name other inhibitors of cell wall synthesis (NOT B-lactams)

1. vancomycin
2. phosphomycin
3. bacitracin
4. cycloserine

3

mechanism of action - cephalosporins?

activate cell wall autolytic enzymes through blocking of terminal cross-linking of peptidoglycan (will interfere w/ forming new cell walls)

4

how are cephalosporins classified?

semisynthetic cephalosporins for clinical use classified as:
1. first generation
2. second generation
3. third generation
4. fourth generation

5

re: cephalosporins, what do "R1" or "R2" mean?

- R1 = substitutions determine degree of antibacterial activity
- R2 = affects pharmacokinetic properties

6

to which group are cephalosporins related to CHEMICALLY?

- penicillins

7

what structure do cephalosporins have?

- beta lactam ring structure

8

what in cephalosportins increases resistance to beta lactamase?

7-methyl group
(similar to penicillins, but protected from degradation by beta lactamase)

9

characteristics of FIRST GEN CEPHALOSPORINS

NARROW SPECTRUM CEPHALOSPORINS
- good activity against G+ bacteria
- moderate activity against G- organisms (E coli, Kleb, Proteus)
- MOST G+ COCCI ARE SUSCEPTIBLE, MSSA! (enterococci, MRSA, S.epidermis = resistant)
- alternative for penicillin allergies
- some acid resistant
- increased b-lactamase resistance
- renal excretion
cefazolin = DOC for surgical prophylaxis

10

what is the DOC for surgical prophylaxis?

cefazolin

11

list first generation cephalosporins

CEFAZOLIN (kefzol, ancef) - IV, IM
cephalothin (keflin) - IN, IM
cephalexin (keflex) - oral

12

characteristics SECOND GEN CEPHALOSPORINS

INTERMEDIATE SPECTRUM CEPHALOSPORINS
- lower activity against G+
- somewhat INCREASED activity against G- negatives (E coli, pleb, proteus)
- NO ANTISPEUDOMONAL activity
- increased b-lactamase resistance
- some acid resistant
- mostly renal excretion

13

list second generation cephalosporins

CEFACLOR (ceclor) - oral
cefuroxime (zinacef) - IV, IM
cefprozil (cefzil) - oral

14

characteristics THIRD GEN CEPHALOSPORINS

BROAD SPECTRUM CEPHALOSPORINS
- less active against G+ cocci
- much more active against Enterobacteriaceae incl penicillinase producing strains
- some active against Pseudomonas (when combined w/ aminoglycosides)
- some acid resistant
- increased B-lactamase resistance
- most excreted by kidney

15

list third generation cephalosporins

- CEFTRIAXONE (rocephin) - neisseria
- Cefotaxime sodium (claforan)
- Cefoperazone (Cefobid) - P. aeruginosa
- Ceftazidime (fortaz)
- Cefixime (suprax) - oral

16

list third generation cephalosporins CNS PENETRATION

- CEFTRIAXONE (rocephin) - neisseria
- Cefotasime sodium (claforan)
- Cefoperazone (Cefobid) - P. aeruginosa

17

which third generation cephalosporin DOC for N. gonorrhoeae? (and contraindications?)

- CEFTRIAXONE (rocephin) - neisseria
- not for use in neonates (bilirubin displacement)

18

which third generation cephalosporin should be avoided for use in patients with hepatic insufficiency? Why?

- Cefoperazone (Cefobid) - P. aeruginosa
- metabolized by liver

19

characteristics FOUR GEN CEPHALOSPORINS

- comparable to 3rd gen
- more resistant to some B-lactamase
- ANTIPSEUDOMONAL
- BETTER G+ coverage
- renal excretion
- BROADEST COVERAGE: enterobacteriaceae, MSSA, pseudomonas
- empirical therapy, particularly when resistance to B-lactamases are anticipated

20

list fourth generation cephalosporins

Cefepime (maxipime) - IV
- best overall coverage of cephalosporins (esp for G+ w/ resistance to B-lactamase)

21

characteristics of "UNNAMED" GEN CEPHALOSPORINS

- FDA approved 2010
- NO ANTIPSEUDOMONAL ACTIVITY
- activity against G+ and G-, approved for CABP
- renal excretion
- MRSA & VRSA COVERAGE - ONLY BETA LACTAM ACTIVE AGAINST MRSA

22

list "unnamed" generation cephalosporins

- ceftaroline fosamil (teflaro) - IV
(can bind to PBP2A w/ high affinity that other beta lactams can't bind to)

23

DOC moraxella catarrhalis?

second or third gen cephalosporin

24

DOC neisseria gonorrhoeae?

- ceftriaxone
- cefixime

25

DOC E. coli, Klebsiella, Proteus?

first or second generation cephalosporin

26

DOC Salmonella?

third generation cephalosporin

27

DOC penicillin resistant Strep pneum?

ceftriaxone

28

DOC Borrelia burgdorferi? (lyme dz)

ceftrioxone (late disease)

29

toxicity of cephalosporins?

- fairly safe
- SUPERINFECTIONS (enterococci, G- bacilli, pseudomembranous colitis or candida)
- disulfiram-like run after alcohol consumption
- ALLERGY (10% cross sensitivity w/ PCN), rash, urticaria, fever, eosinophilia
- direct & indirect positive Coombs test
- GI --> anorexia, nausea, vomiting, diarrhea
- DOSE DEPENDENT RENAL TUBULAR NECROSIS (synergistic nephrotoxicity w/ aminoglycosides)

30

characteristics of monobactams

- drugs w/ monocyclic b-lactam ring
- relatively resistant to b-lactamases
- ACTIVE ONLY AGAINST AEROBIC G-RODS (incl pseudomonas, serratia, klebsielle, proteus)
- no activity against G+ or anaerobes
- parenteral admin
- few side effects (phlebitis, skin rash, abnormal liver function)
- no cross sensitivity w/ other b-lactams (good for PCN allergic)

31

list of monobactams

Aztreonam (Azactam) = only monobactam

32

list of carbapenems

- imipenem; cilastatin (primaxin)
- meropenem (merrem)
- ertapenem (invanz)

33

characteristics of IMIPENEM & MEROPENEM (carbapenems)

- given IV
- broad spectrum activity (incl anaerobes, G+, G-
- stable against B-lactamases
- pseudomonas may develop resistance quickly so use w/ aminoglycosides recommended

34

which carbapenem is the DOC for B-lactamase producing Enterobacter infections?

Imipenem or Meropenem

35

Which carbapenem can cause seizures in high levels?

IMIPENEM - use cautiously w/ patients in renal failure, brain lesions, head trauma, hx of CNS disorders (ie: seizures)

*MEROPENEM less likely to cause seizures

36

"__________ is rapidly inactivated by renal tubule dihydropepdidases and must be given w/ ________, a dihydropeptidase inhibitor."

"IMIPENEM is rapidly inactivated by renal tubule dihydropepdidases and must be given w/ CILASTATIN, a dihydropeptidase inhibitor."

*MEROPENEM is not activated by dihydropeptidases and does NOT need cilastatin!

37

characteristics of Ertapenem (carbapenem)

- highly stable against B-lactamases
- activity against wide variety of G+, G- and anaerobic microorganisms, particularly Enterobacteriaceae
- less active against Pseudomonas (should not be used)
- IV, IM admin - 95% protein binding, renal elimination

38

mechanism of VANCOMYCIN

prevents transpeptidation of peptidoglycan chain, binds to terminal D-ala-D-ala

39

when to use Vancomycin?

- against penicillin and MRSA infections
- to treat G+ infections in PCN allergic pts (parenteral) (effective only G+)
- to treat super infections of Staph, Clostridium dificil (even though first choice = METRONIDAZOL)

40

what is DOC for clostridium dificil?

metronidazol (vancomycin not first choice)

41

why is vancomycin drug of last resort for MRSA?

VRE - emergence of vancomycin resistant Enterococci and need for alternative MRSA treatment

42

adverse effects of vancomycin?

- can cause thrombophlebitis on IV injection
- OTOTOXIC
- NEPHROTOXIC
- "red man syndrome" = flushing from histamine release

43

mechanism of FOSFOMYCIN (monurol)

inhibits cell wall synthesis at one of first steps in synthesis of peptidoglycan analog of phosphoenolpyruvate (prevents NAG to NAM reduction), structurally unrelated to other drugs

44

characteristics of fosfomycin

- active against both G+ and G-
- oral, excreted by kidney
- used for uncomplicated lower UTIs in women
- combo of fosfomycin & B-lactam, amino glycoside or fluoroquinolone may be synergistic

45

mechanism of BACITRACIN?

interferes w/ final dephosphorylation step in phospholipid carrier cycle, can't transport NAG-NAM across inner membrane

46

characteristics of bacitracin

- parenteral (rare) and topical polypeptide antibiotic
- active against G+ bacteria
- commonly used in combo w/ neomycin & polymyxins, which are active against G- bacteria
- parenteral bacitracin used rarely due to risk of NEPHROTOXICITY
- usually used to prevent superficial skin/eye infections following minor injuries

47

mechanism of CYCLOSERINE (seromycin)?

inhibits D-ala from being incorporated into peptidoglycan pentapeptide

48

characteristics of cycloserine

- second line, broad spectrum antibiotic used in treatment of active pulmonary and extra pulmonary TB & UTIs
- can be bacteriosteric or bactericidal

49

adverse effects of cycloserine

- involve CNS (headache, depression, psychosis)

50

what is used to treat moraxella catarrhalis? (G- cocci, aerobic)

TMP-SMZ, cephalosporin (2nd or 3rd gen)

51

what is used to treat neisseria gonorrhoeae? (G- cocci, aerobic)

ceftriaxone or cefpodoxime

52

what is used to treat neisseria meningitidis? (G- cocci, aerobic)

Pen G

53

what is used to treat Enterovacter, Citrobacter, Serratia? (Gram - rods, aerobic)

TMP-SMZ, quinolone, carbapenem

54

what is used to treat shigella? (Gram - rods, aerobic)

quinolone

55

what is used to treat salmonella? (Gram - rods, aerobic)

TMP-SMZ, quinolone, cepholosporin (3rd gen)

56

what is used to treat brucella species? (Gram - rods, aerobic)

doxycycline + rifampin or aminoglycosides

57

what is used to treat helicobacter pylori? (Gram - rods, aerobic)

bismuth + metronidazole + tetracycline or amoxicillin

58

what is used to treat psuedomonas? (Gram - rods, aerobic)

antipseudomonal penicillin + aminoglycoside

59

what is used to treat stenotrophomonas maltophilia? (Gram - rods, aerobic)

TMP-SMZ

60

what is used to treat legionella species?

azithromycin + rifampin or quinolone + rifampin

61

what is used to treat Strep pneum? (Gram + cocci)

PCN

62

what is used to treat Strep pyogenes? (Gram + cocci)

PCN, clindamycin

63

what is used to treat Strep agalactiae? (Gram + cocci)

PCN (+ aminoglycoside?)

64

what is used to treat viridans strep? (Gram + cocci)

PCN

65

what is used to treat Staph aureus, B-lactamase neg? (Gram + cocci)

PCN

66

what is used to treat Staph aureus, B-lactamase pos? (Gram + cocci)

PCN resistant PCN

67

what is used to treat methicillin resistant? (Gram + cocci)

vancomycin

68

what is used to treat Enterococcus species? (Gram + cocci)

PCN + aminoglycoside

69

what is used to treat Bacillus species, non-anthracis? (Gram + rod, aerobic)

vancomycin

70

what is used to treat listeria? (Gram + rod, aerobic)

Ampicillin (+ aminoglycoside?)

71

what is used to treat Nocardia species? (Gram + rod, aerobic)

Sulfadiazine, TMP-SMZ

72

What is used to treat Borrelia recurrentis? (Spirochetes)

doxycycline

73

what is used to treat borrelia burgdorferi (early)? (Spirochetes)

doxycycline, amoxicillin

74

what is used to treat borrelia burgdorferi (late)? (Spirochetes)

Ceftriaxone

75

what is used to treat Leptospira species? (Spirochetes)

PCN

76

what is used to treat Treponema? (Spirochetes)

PCN