Lesson 10: Cephalosporins and Cephamycins

cephalosporin c

cephalosporins are developed from?

cephalosporium acremonium

cephalosporins are isolated from what fungus?

streptomyces

cephamycins are cephalosporin related drugs derived from what spp?

beta-lactam ring

cephalosporin and cephamycins are structurally related to benzylpenicillin. what do they have in common?

beta-lactamase

unlike penicillins, cephalosporins are resistant to this enzyme produced by staph

ph

cephalosporins discovered before 1975 used to be spelled with?

f

cephalosporins discovered after 1975 are spelled with?

generation

cephalosporins are often classified by?

• separated based on the chronology of their development, in vitro potency, and spectrum of activity

2nd, 3rd

wc cephalosporin generations have peculiarities in their spectrum?

1st gen

gen introduced in human med in the 60s and 70s

• broad-spectrum (affects g+)

penicillinase-producing staphylococci

1st gen cephalosporin affects most g+ bacteria including

e. coli, salmonella, proteus, klebsiella, shigella

g- bacteria the 1st gen cephalosporin affects (espks)

streptococcus faecalis, pseudomonas

1st gen cephalosporin is inactive against wc bacteria?

2nd gen

gen of cephalosporin introduced in the 70s

• have increased g- spectrum

g-

2nd generation cephalosporin are more resistant to (G+/G-) beta-lactamase

klebsiella, proteus, providencia, enterobacter

g- strains of bacteria the 2nd gen of cephalosporin affects (kppe)

g+, penicillinase-producing staphylococci

2nd gen cephalosporin have some decreased activity against (G+/G-) bacteria, most noticeable w ________-_______ _______

cefoxitin

specific 2nd gen cephalosporin wc has increased activity against anaerobes

pseudomonas

2nd gen cephalosporin are all inactive against what bacteria?

3rd gen

gen of cephalosporin introduced in the early 80s

• primarily w the g- spectrum

• greatly enhanced resistance to g- beta-lactamase

• decreased activity against g+ cocci

3rd gen

this gen of cephalosporin have some activity against pseudomonas, but activity varies among compounds

4th gen

this gen of cephalosporin has increased stability from hydrolysis by beta-lactamases

cefepime

example of a 4th gen cephalosporin

cephalosporins

used to be considered “second-line” antibiotics, but are now used as first choice in many infxns

klebsiella

cephalosporins are the drug of choice against what bacteria?

cephalosporinase

some bacteria produce this beta-lactamase wc can inactivate both cephalosporins and penicillin

penicillinase, beta-lactamase

cephalosporins are resistant to ________, but vary in their susceptibility to ____-_________

1st, 2nd

gens wc are adequately absorbed when administered orally

parenterally

except the 1st and 2nd gens, how should the other cephalosporins be administered?

intramuscular

all cephalosporins are absorbed when administered in what way?

extracellular fluid, pericardial fluid, pleural fluid, bile, infected bones

where are cephalosporins distributed?

csf

in the absence of acute inflammation, cephalosporins do not reach useful levels in the?

cefuroxime, moxalactam, cefotaxime, ceftizoxime

cephalosporins wc penetrate into the csf in sufficient concentrations to treat meningitis

glomerular filtration, tubular secretion

most cephalosporin are excreted unchanged in the urine by what processes?

cephalothin, cephapirin, cefotaxime

cephalosporins metabolized in the liver thru deacetylation

cefoperazone, moxalactam

cephalosporins excreted primarily in the bile

false

TRUE OR FALSE: cephalosporins have high incidence of adverse reactions

hypersensitivity reactions

most common adverse reaction of cephalosporins

renal toxicity

adverse reaction wc manifests as renal tubular necrosis

cephaloridine

most nephrotoxic of the cephalosporins

cephalothin

renal toxicity is also well documented on this cephalosporin, wc is toxic at high doses or in px w renal failure

aminoglycosides, diuretic furosemide

nephrotoxicity of cephalosporins may be enhanced w concurrent use of what drugs?

gi disturbances, local irritation, pain from iv, thrombophlebitis from iv, drug fever, non-specific lymphadenopathy, bone marrow depression

other toxicities of cephalosporins

1st gen

gen of cephalosporin most used in vetmed and is the least expensive

bone infections (osteomyelitis)

1st gen cephalosporins are often used to treat what infxn?

1st gen

gen of cephalosporin used prophylactically in surgery especially for prosthesis implants

cefadroxil, cephalexin, cephaglycin, cephradin

1st gen oral ceph

cephaloridine, cephalothin, cephapirin

1st gen parenteral ceph

2nd gen

gen of cephalosporin used extensively in vetmed

• used primarily to treat klebsiella infxns and some other resistant g- infxns

cefaclor, cefuroxime

2nd gen oral ceph

cefuroxime, ceforanide, cefoxitin

2nd gen parenteral ceph

3rd gen

gen of cephalosporin rarely used in vetmed and are very expensive

ceftriaxone, ceftazidime, cefmenoxime, cefixime

3rd gen oral ceph

cefotaxime, cefoperazone, moxalactam, ceftiofur, ceftizoxime

3rd gen parenteral ceph

moxalactam

an oxa-beta-lactam (replaces sulfur), slightly more active against pseudomonas than other 3rd gen, except cefoperazone

moxalactam

the best of the 3rd gen cephalosporins against anaerobes, about equal w cefoxitin

cephamycin

is cefoxitin a cephalosporin or cephamycin?

cefoperazone

the most active cephalosporin against pseudomonas

antipseudomonal penicillin, aminoglycosides

cefoperazone may be the most active cephalosporin against pseudomonas, but what are the primary drugs of choice for this bacteria?

bleeding problems

what adverse reaction has been noted w the use of cefoperazone?

4th gen

gen of cephalosporin used in the tx of infxns due to g- bacilli resistant to 3rd gen cephalosporins