Pharm 43 Beta Lactams By Tracy-Jo

Front 1

what are the Beta-lactam cmpds

Back 1

penicillin, cephalosporins, monobactams, carbapenems and beta-lactamase inhibitors (beta lactams named for unique lactam ring)

Front 2

what is structure of all penicillins

Back 2

thiazolidine ring attached to beta-lactam ring carries secondary amino group (RNH-)

Front 3

what structure of penicillin is essential for biologic activity

Back 3

6-aminopenicillanic acid

Front 4

bacterial Beta-lactamases hydrolze the beta-lactam ring resulting in

Back 4

peniciloic acid which lacks antibacterial activity

Front 5

Penicillins can be assigned to one of three groups

Back 5

penicllins (penicillin G), antistaphylococcal penicillins (nafcillin) and extended spectrum penicillins (ampicillin and antispeudomonal penicillins)

Front 6

what are penicllins most active against

Back 6

gram-positive organisms, gram-negative cocci, and non-beta-lactamase producing anaerobes

Front 7

what do penicillins have little activity against

Back 7

gram-negative rods, and they are susceptible to hydrolysis by beta-lactamases

Front 8

what are antistaphylococcal penicillins resistant to

Back 8

staphylococcal beta lactamases

Front 9

what are antistaphylococcal penicillins active against

Back 9

staphylococci and streptococci

Front 10

what are antistaphylococcal penicillins NOT active against

Back 10

enterococci, anaerobic bacteria and gram negative cocci and rods

Front 11

like penicillins extended spectrum penicillins (ampicillin..) are susceptible to

Back 11

hydrolysis by beta-lactamases

Front 12

extended spectrum penicillins (ampicillin..) are active against full spectrum of penicillin and have improved activity against

Back 12

gram negative organisms

Front 13

Most penicillins are dispensed as the _______or________salts of the free acid

Back 13

sodium or potassium

Front 14

procaine and benzathine salts or penicillin G provide repository froms for what kind of administration

Back 14

IM injection

Front 15

Penicillins inhibit bacterial growth by interfering with the ______reaction of_____-

Back 15

transpeptidation reaction of bacterial cell wall synthesis

Front 16

Penicillin binding protein (PBP) removes the terminal ____ in the process of forming a crosslink with nearby peptide

Back 16

alanine

Front 17

Beta-lactam antibiotics covalently bind to the active site of ______; this inhibits transpeptidation reation halting peptidoglycan syntehesis and cell dies

Back 17

Penicillin binding proteins (PBPs)

Front 18

Penicillins and cephalosporins only kill bacterial cells when they are actively

Back 18

growing and synthesizing cell wall

Front 19

Resistance to penicillin is one of four mechanisms

Back 19

inactivation of antibiotic by beta-lactamase, modification of target PBPs, mod of target PBPs and efflux

Front 20

what is the most common mechanism of resistance

Back 20

beta-lactamase

Front 21

carbapenems are highly resistant to hydrolysis by

Back 21

penicillinases and cephalosporinases; but are hydrolyzed by metallo-beta-lactamase and carbapenemases

Front 22

what is mechanism of methicillin resistance in staphylococci

Back 22

altered target PBPs

Front 23

MOA of penicllin

Back 23

Block cell wall synthesis by inhibiting peptidoglycan cross-linkage

Front 24

Penicillins active against penicillinase secreting bacteria

Back 24

Methicillin, nafcillin, and dicloxacillin

Front 25

Class of antibiotics that have 10% cross sensitivity with penicillins

Back 25

Cephalosporins

Front 26

Cheap wide spectrum antibiotic DOC of otitis media

Back 26

amoxicillin

Front 27

what is mechanism of pennicillin resistance in pneumococci and enterococci

Back 27

altered target PBPs

Front 28

some resistant organisms produce PBPs with low affinity for binding beta-lactam antibiotics, therefore they are not

Back 28

inhibited

Front 29

resistance due to impaired penetration of antibiotic to target PBPs occurs only in

Back 29

gram-negative species bc of their impermeable outer cell wall membrane (absent in gram +)

Front 30

beta-lactam antibiotics cross outer membrane and enter gram negative via

Back 30

outer membrane protein channels (porins)

Front 31

what is the efflux pump that some of the gram - organisms may produce

Back 31

consists of cytoplasmic and periplasmic protein components that transport some beta-lactam antibiotics from the periplasm back across the outer membrane

Front 32

what antistaphylococcal penicillin is not suitable for oral administration

Back 32

nafcillin (GI absorption is erratic)

Front 33

what penicillins are acid-stable and relatively well absorbed

Back 33

ampicillin, dicloxacillin, amoxicillin

Front 34

absorption of most oral penicillins is impaired by food except

Back 34

amoxicillin

Front 35

at what percentage does protein binding of penicillins become clinically relevant

Back 35

95%

Front 36

what formulation of a single dose of penicillin can treat beta-hemolytic strep infection for 10 days

Back 36

benzathine penicillin IM 1.2 million units (serum levels 0.02 mcg/ml for 10 days; after 3 wks still high enough to prevent)

Front 37

penicillin is excreted rapidly by kidneys 10% in glomerular filtration and 90% by

Back 37

tubular secretion

Front 38

what is normal half life of penicillin

Back 38

30 minutes (renal failure 10 hrs)

Front 39

what is half life of ampicillin and extended spectrum penicillins

Back 39

1hr

Front 40

dose must be adjusted according to renal fxn with 1/4 to 1/3 normal does if ___________ is 10 ml/min or less

Back 40

creatinine clearance

Front 41

how is nafcillin cleared from the body

Back 41

primarily biliary excretion

Front 42

how are oxacillin, dicloxacillin and cloxacillin eliminated

Back 42

kidney and biliary (no dosage adjustment is reqd in renal failure)

Front 43

most penicillins should not be given with food becuz

Back 43

binds to food proteins and acid inactivation

Front 44

what can be given to raise blood levels of penicillin

Back 44

probenecid - impairs renal tubular secretion of weak acids such as beta-lactam compounds

Front 45

what is drug of choice for infections by strepto, meningo, entero, penicillin-susc pneumococci, non-beta lact staph, treponema pallidum, clostridium, actinomyces…

Back 45

pencillin G

Front 46

what drug is often replaced by amoxicillin because of its poor bioavailability, frequent dosing and narrow spectrum

Back 46

Penicillin V

Front 47

a single IM injection of ________ is effective for beta hemolytic strep pharyngitis for prevention

Back 47

benzathine penicillin 1.2 million units given IM every 3-4 wks for prevention

Front 48

what is dosing of benzathine Penicillin G is effective in treating syphilis

Back 48

2.4 mill units IM once/week 1-3 weeks

Front 49

Penicillins resistant to staph beta lactamase (methicillin, nafcillin and isoxazolyl pens) are

Back 49

semisynthetic pens indicated for infection by beta lactamase producing staph (some streptococci and pneumococcis are also susceptible)

Front 50

what organisms are resistant to methicillin, naficllin and isoxazolyl pens

Back 50

listeria, enterococci and methicillin resistant strains of staph

Front 51

what is suitable for treatment of mild to moderate localized staph

Back 51

isoxazolyl pen such as oxacillin, cloxacilln or dicloxacillin (0.25-0.5g orally every 4-6 hrs); acid stable and reasonable bioavail; food interferes

Front 52

what is given for serious systemic staphy infections

Back 52

oxacillin or nafcillin 8-12 g/d by intermittent IV infusion 1-2 g/every 4-6hrs

Front 53

what are the extended spectrum penicillins

Back 53

aminopenicillins, carboxypenicillins, ureidopenicillins; greater activity against gram negs bc can better penetrate outer memb

Front 54

like Penicillin G, ____________penicillins are inactivated by betat-lactamases

Back 54

extended spectrum

Front 55

what drugs are given to treat UTIs, sinusitis, otitis and LRIs (extended spectrum)

Back 55

aminopenicillins - amoxicillin and ampicillin

Front 56

what are the prefferred beta-lactam antibiotics for treating infections suspected by pen-resistant pneumococci

Back 56

ampicillin and amoxicillin

Front 57

which aminopenicillin is effective for shigellosis

Back 57

ampicillin

Front 58

treatment with this drug is controversial for salmonella gastroenteritis as ti may prolong the carrier state

Back 58

ampicillin

Front 59

ampicillin at 4-12 g/d IV is useful for treating the followin serious infections

Back 59

pen-susceptible organisms, anerobes, enterococci, listeria and beta-lactamase neg strain of gram neg cocil and bacilli as E coli and salmonella

Front 60

what strains are emerging resistant to ampicillin due to altered PBPs

Back 60

are generally susceptible but some non-beta lactamase producing strains of H influenzae

Front 61

ampicillin is not active against

Back 61

klebsiella, enterobacter psuedomonas aeruginosa, citrobacter, serratia, indole proteus sp, and other gram - aerobes common in nosicomal infections

Front 62

although carbenicillin is obsolete, a carbenicillin indanyl sodium can be used to treat

Back 62

UTIs - but there are more active better tolerated alternatives

Front 63

ticarcillin is less active than ampicilliin against

Back 63

enterococci

Front 64

antipseudomonal pen is used in combo with aminoglycoside or fluoroquinolone for pseudomonal infections outside the

Back 64

urinary tract

Front 65

ampicillin, amoxicillin, ticarcillin and piperacillin available in combo with beta lactamase inhibitors

Back 65

clavulanic acid, sulbactum or tazobactam - extends activity of these pens to include beta lactamase producing strains of S. aureus as well as some gram - bacteria.

Front 66

most of the serious adverse effects of penicillin are due to

Back 66

hypersensitivity; antigenic determinants are degradation products of pens, penicilloic acid and products of alkaline hydrolysis bound to host protein

Front 67

allergic rxns to pen include

Back 67

anaphylaxis, uticaria, feer, joint swelling, pruritu, resp embarrassment, skin rashes

Front 68

large doses of pen given orally may lead to

Back 68

GI upset, N/V/D

Front 69

what penicillins can cause skin rashes that are not allergic in nature

Back 69

ampicillin and amoxicillin

Front 70

_______are similar to pens but more stable to many beta lactamases there4 have a broader spectrum of activity

Back 70

Cephalosporins

Front 71

what organisms are becoming a problem in hydrolyzing most cephalosporins

Back 71

Ecoli and klebsiella; methicillin resistant strains of staph

Front 72

cephalosporins are not active against

Back 72

enterococci and L. monocytogenes

Front 73

first generation cephalos include

Back 73

cefadroxil, cefazolin, cephalexin, cephalothin, cephapirin and cephradine

Front 74

first generation cephalos very active against

Back 74

gram + cocci, such as pneumococci, streptococci and staph

Front 75

anaerobic cocci (peptococcus, peptostreptococcus..) are usually sensitvite to ____________but bacteroides fragilis is not

Back 75

first gen cephalosporins

Front 76

which is the only first gen parenteral cephalo still in use

Back 76

cefazolin

Front 77

oral cephalosporins should not be relied on in serious systemic infections, may be used for treatment of

Back 77

UTI, staph/strep infections like cellulitis or soft tissue abcess

Front 78

what cephalosporin is drug of choice for surgical prophylaxis

Back 78

cefazolin (does not penetrate CNS and thus not used in meningitis)

Front 79

what is an alternative to antistaph penicillin for patients allergic to pen

Back 79

cefazolin

Front 80

what are the members of the second generation of cephalosporins

Back 80

cefaclor, cefamandole, cefonicid, cefuroxime, cefprozil, loracarbef, ceforanide (related cephamycins - cefoxitin, cefmetazole, and cefotetan)

Front 81

cephamycins - cefoxitin, cefmetazole, and cefotetan have activity against

Back 81

anaerobes

Front 82

second generation cephalosporins have activity against orgs inhibited by 1st gen plus

Back 82

extended gram - coverage

Front 83

as with first generation, no second gens are active against

Back 83

enterococci or P. aeruginosa

Front 84

of the second generations given orally, all but cefuroxime should be used against

Back 84

penicillin resistant pneumococci

Front 85

which 2nd gen is more susceptible to beta-lactamase hydrolysis compared with other agents and thus usefulness diminished

Back 85

cefaclor

Front 86

oral 2nd gen cephalosporins active against beta lactamase producing

Back 86

H influenzae or moraxella catarrhalis; used to treat sinusitis, otitis, LRI

Front 87

bc of activity against anaerobes cefoxitin, cefotetan or cefmetazole can used to treat

Back 87

peritonitis or diverticulitis

Front 88

what should not be used to treat meningitis altho it crosses blood brain barrier

Back 88

cefuroxime - less effective than ceftriaxone or cefotaxime (3rd gens)

Front 89

third generation cephalosporins include

Back 89

cefoperazone, cefotaxime, ceftazidime, ceftizomxime, ceftraixone, cefixime, cefpodoxime, cefdinir..

Front 90

what is special about 3rd gen cephalo

Back 90

expanded gram - coverage and some are able to cross blood brain barrier