Cephalosporins Gen 1-4 Flashcards Preview

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Flashcards in Cephalosporins Gen 1-4 Deck (59)
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1
Q

What is different between the structure of cephalosporins and the structure of penicllins?

A

cephalosporins have 6-membered ring attached to beta lactam (house w/ basement and garage), while penicllins have a 5-membered ring attached to the beta lactam ring (house w/ garage)

2
Q

What organism are cephalosporins inherently active against that immediately attracted attention?

A

MSSA

3
Q

Which cephalosporin is the parent compound of all modern cephalosporins?

A

Cephalosporin C

4
Q

Side group at the ___ and ___ positions can be manipulated in cephalosporins.

A

3, 7

5
Q

The N-methylthiotetrazole side chain is abbreviated as the…

A

NMTT chain

6
Q

What does the NMTT chain block?

A

production of prothrombin (needed for clotting)

7
Q

Cephalosporins with the NMTT side chain + alcohol results in the ________ reaction (so named because of an anti-alcoholic drug that caused intense nausea/vomiting when it came in contact with alcohol).

A

antabuse

8
Q

When did the 1st generation cephalosporins come out?

A

late 1950s

9
Q

Which company held the patent on Cefazolin (1st gen parenteral) and Cephalexin (1st gen oral)

A

Eli Lilly

10
Q

Which three cephalosporins have oxyimino side chains in the 7 position, and what generation are they part of?

A

cefotaxime (parenteral), ceftriaxone (parenteral), ceftazidime (anti-pseudomonal, parenteral); 3rd generation

11
Q

What does the oxyimino side chain hydrolyze?

A

extended-spectrum beta lactamases (to a point)

12
Q

Which three cephalosporins cross the blood-brain barrier and so can be used to treat meningitis?

A

cefotaxime (3rd gen parenteral), ceftriaxone (3rd gen parenteral), ceftazidime (3rd gen parenteral, anti-pseudomonal)

13
Q

Which common cephalosporin has an NMTT side chain in the 3 position and is therefore subject to the antabuse reaction and prothrombin inhibition?

A

cefpodoxime (3rd gen oral)

14
Q

What is the only monobactam?

A

aztreonam

15
Q

What differentiates a monobactam from the other beta lactams?

A

it has no side chains (just a beta lactam ring)

16
Q

What are the four carbapenems?

A

imipenem, meropenem, ertapenem, doripenem

17
Q

What are the two components of imipenem?

A

thienamycin, cilastatin

18
Q

The 7-alpha-methoxy side chain gives cephalosporins…

A

anaerobic activity, AmpC (beta lactamase) hydrolysis ability

19
Q

What is the most widely used of all the cephalosporins today?

A

cefazolin

20
Q

What are the four first generation parenteral cephalosporins? Which is still popular today?

A

cefazolin, cephalothin (keflin), cephapirin (cephadyl), cephradine (velocef); cefazolin still popular

21
Q

What are three first generation oral cephalosporins; which is still popular?

A

cephalexin (keflex), cephradine (velocef), cefadroxil (duracef); cephalexin still popular

22
Q

What organisms do first generation cephalosporins have good activity against?

A

MSSA, streptococci

23
Q

What organisms do first generation cephalosporins have moderate activity against?

A

Escherichia coli, Klebsiella pneumoniae, proteus mirabilis (some enteric GNRs)

24
Q

What organisms do first generation cephalosporins have poor activity against?

A

enterococci, anaerobes, MRSA, pseudomonas

25
Q

Why is cephalothin (1st gen parenteral) not good for prophylactic treatment, even though it has the best anti-staphylococcal activity?

A

it has a very short half-life (about 30 minutes)

26
Q

Which 1st generation cephalosporin has the longest half-life (about 2 hours)?

A

cefazolin

27
Q

Do any of the 1st generation cephalosporins enter the cerebral spinal fluid?

A

no

28
Q

What is the likelihood of cross-reactivity between penicillin allergies and 1st generation cephalosporins?

A

3-5%

29
Q

What are the six second generation parenteral cephalosporins? Which are still popular today?

A

cefamandole (mandol), cefoxitin (mefoxin), cefuroxime (ceftin), cefotetan (cefotan), cefonicid (monocid), cefmetazole (zefazone); cefoxitin, cefuroxime, cefotetan still popular

30
Q

What are the four second generation oral cephalosporins? Which are still popular today?

A

cefaclor (ceclor), cefuroxime axetil, cefprozil (cefzil), lorcarbacef (lorabid); cefuroxime still popular

31
Q

Which of the second generation cephalosporins are Cefamycins? What differentiates cefamycins from the other 2nd gen cephalosporins?

A

cefoxitin, cefotetan, cefmetazole; cefamycins have anaerobic coverage (moderate activity against B. fragilis although resistance increasing)

32
Q

Which organisms do second generation cephalosporins have good activity against?

A

Haemophilus influenzae, Neisseria, some enteric GNRs

33
Q

Which organisms do second generation cephalosporins have moderate activity against?

A

MSSA, streptococci, anaerobes (only for cefamycins)

34
Q

Which organisms do second generation cephalosporins have poor activity against?

A

enterococci, MRSA, pseudomonas

35
Q

What is the difference in organism coverage between the first and second generation cephalosporins?

A

2nd generation has more gram-negative coverage (because of enhanced beta lactamase stability) but less gram-positive coverage than 1st generation

36
Q

Which two second generation cephalosporins are approved for use against H. influenzae, Strep pneumonia, and Moraxella catarrhalis?

A

cefamandole, cefuroxime

37
Q

Which second generation cephalosporins have an NMTT side chain?

A

cefmetazole, cefotetan, cefamandole

38
Q

Which of the second generation cephalosporins is designed to be dosed once daily because of its extended half life (about 3.5-4 hours)?

A

cefonicid

39
Q

What is the first cephalosporin that was able to enter the cerebral spinal fluid? Is it still used today?

A

cefuroxime; not really used today because too many treatment failures

40
Q

What does INR stand for and what does it refer to?

A

International normalized ratio, refers to clotting time

41
Q

When might you be worried about giving a patient a cephalosporin?

A

if they have a true allergy to penicillin (anaphylaxis, hives, etc.)

42
Q

What differentiates third generation cephalosporins from second generation cephalosporins?

A

3rd generation have enhanced beta lactamase stability, increased ability to penetrate gram-negative cell walls (even poorer gram-positive activity than 2nd)

43
Q

What are the three subgroups of 3rd generation cephalosporins (parenteral)?

A

enterobacteriaceae activity, enterobacteriaceae plus anti-pseudomonal activity, enterobacteriaceae plus antianaerobic activity

44
Q

What are the two 3rd generation parenteral cephalosporins in the enterobacteriaceae activity group?

A

cefotaxime (claforan), ceftriaxone (rocephin)

45
Q

What is the 3rd generation parenteral cephalosporin in the enterobacteriaceae plus anti-pseudomonal activity group?

A

ceftazidime (ceftaz)

46
Q

What is the 3rd generation parenteral cephalosporin in the enterobacteriaceae plus antianaerobic activity group?

A

ceftizoxime (cefizox)

47
Q

What was the first cephalosporin to have anti-pseudomonal coverage?

A

ceftazidime

48
Q

Which 3rd generation cephalosporins are approved for treating gram-negative meningitis?

A

ceftriaxone, cefotaxime

49
Q

Why is ceftizoxime not good for prophylactic treatment even though it has anaerobic coverage?

A

it has very poor gram-positive coverage

50
Q

What are the four oral 3rd generation cephalosporins?

A

cefixime (suprax), cefpodoxime (vantin), cefditoren (spectracef), cefdinir (omnicef)

51
Q

Oral 3rd generation cephalosporins have been highly associated with what?

A

diarrhea from C. difficile

52
Q

Before the 3rd generation cephalosporins (which had gram-negative coverage), what drugs had to be used for treating gram negative infections that had toxic side effects (including deafness, tinnitus, reversible kidney damage, etc.)?

A

aminoglycosides

53
Q

What is the 4th generation cephalosporin?

A

cefepime (maxipime)

54
Q

Which cephalosporin is a zwitterion (dipolar molecule with improved gram-negative cell wall penetration)?

A

cefepime

55
Q

What characteristic other than improved cell wall penetration makes cefepime (4th gen) effective against gram-negative organisms?

A

it is a poor inducer of beta lactamases

56
Q

What organisms does cefepime (4th gen) have good activity against?

A

enterobacteriaceae, pseudomonas aeruginosa, haemophilus influenzae, neisseria gonorrhea, neisseria meningitidis, gram-postiive organisms

57
Q

What organisms does cefepime (4th gen) have poor (or no) activity against?

A

anaerobes, bacteroides fragilis, MRSA (no activity), enterococci (no activity)

58
Q

Can cefepime (4th gen) cross the blood-brain barrier?

A

yes

59
Q

The 4th generation cephalosporin was primarily intended to treat what?

A

hospital-acquired infections, meningitis