Cephalosporins Flashcards
How many people who have PCN allergy are allergic to Cephalosporins?
If the reaction to PCN was anaphylaxis, now what are the chances the patient will exhibit hypersensitivity to cephalosporins?
10%
90%
What do side chains at Cephalosporin R1 confer?
R2?
R1: Antibacterial spectrum activity
R2: Metabolism and Pharmacokinetic properties
What generation Cephalosporin penetrates well into CSF, especially with inflamed meninges?
3rd Generation Ceftriaxone
What is the major route of Cephalosporin excretion?
What relevance does this have on treatment?
Renal Excretion (except Ceftriaxone, Cefoperazone)
Dosage Adjustment required when patient has renal insufficiency
T/F
Following an IV infusion the fifth generation, Ceftaroline fosamil (progdrug), is rapidly converted by plasma phosphateases into active ceftaro line.
TRUE
Describe absorption of oral Cephalosporins.
In what form are oral Cephalosporins administered?
Where are these activated?
How is absorption increased?
rapid, thorough
Oral cephalosporins are available as prodrug esters and nonesterified compounds.
Prodrug esters are Hydrolyzed in the intestines to the active drug.
Food enhances absorption
Are Cephalosporins baceriocidal or bacteriostatic?
Are Cephalosporins Susceptible to some beta-lactamases?
T/F
Efficacy of a particular cephalosporin related to its affinity for PBPs.
Bacteriocidal
YES
TRUE!
What is the Mechanism of Action for Cephalosporins?
A. Bacterial cell walls form by cross-linking of different peptidoglycan strands as the third and final stage of their wall synthesis. The amino group at one end of a pentaglycine chain reacts with the peptide bond between two D-alanine residues. A peptide bond is formed between glycine and one of the D-ala residues, while the other D-ala is released. This cross-linking reaction is catalyzed by glycopeptide transpeptidase or a portionofthe penicillin-binding-proteins(PBPs).
B. The cephalosporins, like penicillin, mimic D-ala-D-ala and, therefore, are incorporated into the active site of the transpeptidase. Once bound, it forms an irreversible covalent bond with a serine of the enzyme and the cross-bridging is halted. Hence, it exhibits cidal activity since the microorganisms can not surive without a formed cell wall.
What generation cephalosporin is a great choice for various bacteria that cause meningitis?
3rd Generation Ceftriaxone
Which 2 Cephalosporins are the only to experience hepatic elimination?
Ceftriaxone
Cefoperazone
Is it okay to try Cephalosporin on a patient with non-IgE mediated hypersensitivity to penicillins?
What about in IgE mediated hypersensitivity to penicillins?
Yes
Fuck NO
What 6 adverse reactions, other than hypersensitivity, are associated with Cephalosporins?
- BLEEDING due to hypoprothrombinemia (disturbance in vitamin K dependent clotting factors by blocking the vitamin K epoxide reductase)–associated with Cephalosporins with N-methylthiotetrazole side chain (e.g. Cefamandole, Cefoperazone, Cefotetan)
- ALCOHOL, DISULFIRAM-like intolerence: Cefamandole, Cefoperazon, Cefotetan (NMTT side-chain)
- INTERSTITIAL NEPHRITIS (rare)
- DIARRHEA (due to those with biliary excretion)
- PSEUDOMEMBRANOUS COLITIS
- SERUM SICKNESS (Cefaclor 2nd-Gen in children)
What is the drug interaction cephalosporins have with Warfarin?
What is the drug interaction cephalosporins have with Probenecid?
potentiation of anticoagulant effects
Prolongs excretion in cephalosporins that have tubular secretion.
Which Cephalosporin is used for preoperative prophylaxis?
Cefazolin (Ancef)
Which Cephalosporins are the only two who can be used against anaerobes?
2 Cefomycins:
Cefotetan (cefotan)
Cefoxitin (mefoxin)
