Walters- Cephalosporins Flashcards
what are cephalosporins made up of?
beta-lactam + dihydrothiazine ring with side chains
what is the main mechanism of cephalosporins?
same as PCNs - inhibit transpeptidase and inhibit cell wall synthesis and cause cell lysis
what is the advantage of a cephalosporin over PCNs?
they are resistant to many PCNases (beta-lactamases)
what do the first generation of cephalosporins resist?
Staph PCNase
what are 3 first generation drugs of cephalosporins?
Cefazolin, Cephalexin, and Cefadroxil
what are the second generation of cephalosporins used against?
less gram positive and more gram negative (than first) - cover PEck and H.influenza and some neisseria (HNPEcK)
what generation is Cefaclor in and when is it used?
2nd generation and orally every 8 hours (associated with serum sickness)
what generation is Cefuroxime in and how is it administered?
2nd - oral = ceftin and IV/IM = Zinacef
what generation is Cefoxitin in and what is it active against?
2nd - Bacteroides fragilis (IV/IM)
what generation is Cefotetan in and what does it do?
2nd - methylthiotetrazole side-chain antagonizes vit K = hypoprothrombinemia (must supplement with vit K)
What coverage do the 3rd generation cephalosporins have?
they have much less gram positive but more gram negative
what generation is Ceftriaxone in and what does it do?
3rd - 85-90% protein bound and easily displaces bilirubin from albumin (do not use if less than 3 months old unless its for gonorrhoeae conjunctivitis)
what does Ceftriaxone have good activity against?
meningitis (strep pneumoniae and N. meningitidis)
what is the FDA warning for Ceftriaxone?
do not use with Ca2+ containing products in patients less than 28 days old - may precipitate in kidneys/lungs and give Rxs sequentially (flush IV between Rxs)
what can Ceftriaxone cause in children?
sludge (pseudolithiasis) - nausea, anorexia, epigastric distress, colic = reversible when discontinued
what generation is Cefotaxime in and how is it used?
3rd - IV/IM, parent and metabolite active and increases the spectrum
what generation is Ceftazidime in and what can it cause?
3rd - neurologic SE e.g. myoclonus, EEG changes with increased risk if epileptic; disorientation
what generation are Cefpodoxime and Cefdinir in are what are they used for?
3rd - oral use (Cefdinir is excreted mostly unchanged = binds Fe and reddens infants faces in infants fed high Fe formula)
what generation is Cefepime in and what does it do?
4th - (IV/IM) for gram - rods resistant to 3rd generation, good for CNS penetration
what are the side effects for Cefepime? and how is it excreted?
neurological - disorientation, myoclonus, EEG changes, mostly renal excretion
what generation is Cefditoren and what happens to the drug during absorption?
4th - pro-Rx = hydrolyzed by esterases during absorption, which activates the drug.
what drug is considered an advanced generation cephalosporin?
Ceftaroline = IV proRx used for community acquired bacterial pneumonia and complicated skin and skin structure infections including MRSA
what are the general side effects of cephalosporins?
hypersensitivity = risk of cross-allergy with PCN (greatest with 1st), nephrotoxicity and risk of immune-mediated hemolytic anemia
