Cephalosporins Flashcards
What is the general structure of cephalosprins?
Beta-Lactam ring
Dihydrothiazine ring - metabolism and pharmacokinetic properties
acyl side chain - antibacterial spectrum activity
Oral cephalosporins are available in what form and how are they metabolized?
Prodrug esters
Hydrolyzed in the intestine to the active drug
What is the MoA of cephalosporins?
Binds to PBPs, inhibiting crosslinking of peptidoglycan strains
Efficacy is related to affinity to PBPs
Why are cephalosporins good for meningitis?
They penetrate the CSF, especially if the meninges are inflamed
How are cephalosporins excreted? What are the exceptions?
Renal excretion
Ceftiaxone, Cefoperazone - Hepatic elimination
What are the adverse effects of cephalosporins?
Hypersensitivity reactions - rash,drug fever
Hematology - bleeding
Alcohol, disulfiram-like intolerannce
GI-Diarrhea, Pseudomembranous colitis
Renal - interstitial nephritis
Immunologic - serum sickness (Cefaclor)
What are the drug interactions associated with cephalorpsorins?
Warfarin - potentiation
Alcohol - only agents with NMTT side chain
Probenecid - prolongs excretion in CSs that have tubular secretion
What do cephalosporins generally not cover?
Enterococcus and MRSA - except ceftaroline
Chlamydia, Mycoplasma, Legionella
Listeria monocytogenes
What is Zerbaxa?
Ceftolozane/tazobactam
Cephalosporin with beta lactamase inhibitor
Approved for complicataed UTIs/pyelonephritis
What is Ayvcaz?
Ceftazidime/avibactam
3rd gen cephalosporin with BL inhibitor
What are the uses for cephalosporins?
Community acquired pneumonia
Nosocomial pneumonia
Meningitis - ceftriaxone
Skin soft tissue
Surgical prophylaxis - cefazolin
Febrile neutropenia
Endocarditis
STD (Neisseria resistant to PCNs)
What is Vabomere?
Meropenem-vaborbactam
complicated UTIs including pyelonephritis
How do carbapenems work?
Binds to PBP resulting in cidal effect
What carbapenem has the longest half life?
Ertapenem (Invanz)
Allows once daily administration
How is imipenem (Primaxin) metabolized?
Extensive renal metabolism
Cilastatin added to prevent renal metabolism
