Cephalosporins are a class of ____________.
cephalosporins are _________ to penicillins.
Cephalosporins are _____________ compared to many bacterial B-lactamases
Cephalosporins have a ____________ of activity.
What is a potential problem with cephalosporins?
strains that express extended-spectrum B-lactamasees can hydrolyze most cephalosporins
Chephalosporins not active against?
- L monocytogenes
What is the nucelus of cephalosporins?
- 7-aminocephalosporanic acid
- (closely resembles nucleus of penicillins)
The intrinsic antimicrobial activity of natural cephalosporins is ________, but adding an R group yields hundreds of ________ compounds with _____________.
- potent compounds
- low toxicity
What was the first synthetic cephalosporin?
Cephalosporin Mechanism of action?
- same mode of action as other B-lactam antibiotics
- less susceptible to penicillinases
- disrupt synthesis of peptidoglycan layer of bacterial cell wall.
First generation Cephalosporins active against ______________ and not generally active against ____________
- gram+ cocci(pneumococci,streptococci,staphylococci)
- methicillin-resistant strains of staphylococci (new compounds developed for this though)
What are the 1st gen oral cephalosporins?
cephalexin, cephradine, cefadroxil
After oral doses of 500mg of 1st gen serum levels are
After oral dose of 1st gen urine conc are usually __________ but in tissue they are variable and generally __________ than in serum
Excretion of 1st gen oral cephalosporins is done by
- glomerular filtration
- tubular secretion (drugs that block this (probenecid) may increase serum levels)
What is the only 1st gen ceph for parenteral use still in use? and whats its dose?
- for adults 0.5-2g IV q 8 hr
- (excretion by kidney and dose adjustments required for renal impaired)
What is the indication for 1st gen oral cephalosporins? What are they not indicated for?
- streptococcal infections (cellulitis and soft tissue abscess)
not used for serious systemic infection
What is the indications for cefazolin (parenteral 1st gen)? what is it not used for?
- Drug of choice for surgical prophylaxis
- staphylococcal or streptococccal infection for people who have pen allergy
- alternate for antistaphylococcal penicillin if pt allergic to pen
not for meningitis cuz it doesn't penetrate CNS
What are the 2nd generation cephalosporins?
- Structurally related cephamycins, cefoxitin, cefmetazole, cefotetan have activity against anaerobes
What are 2nd gen ceph active against? and not active against?
- active against organisms inhibited by 1st generation drugs
- greater gram neg spectrum
- more resistant to B-lactamase
Not active against enterococci or P. aeruginosa