Beta-lactams II Flashcards
The cephalosporins are all natural or synthetic derivatives of ____ derived from ____ ____.
The cephalosporins are all natural or synthetic derivatives of CEPHALOTHIN derived from CEPHALOSPORIUM ACREMONIUM.
What is the mechanism of action of cephalosporins?
Inhibit cell wall synthesis at the 3rd step in peptidoglycan synthesis
Are cephalosporins bacteriocidal or bacteriostatic?
Bacteriocidal
What is the mechanism of action for carbapenems?
Inhibit cell wall synthesis at the 3rd step in peptidoglycan synthesis
What is the mechanism of action for monobactams?
Inhibit cell wall synthesis at the 3rd step in peptidoglycan synthesis
What is the mechanism of action for bacitracin?
Inhibit cell wall synthesis at the 2nd step (pyrophosphate) instead of PBP
Cephalosporins are not usually sensitive to ____, ____, or ____.
Cephalosporins are not usually sensitive to CLAVULANOIC ACID, SULBACTAM, or TAZOBACTAM.
Which group has more resistance problems, penicilllins or cephalosporins?
Penicillins - penicillinases are more common than cephalosporins.
Hypersensitivity to penicillins does not always lead to cephalosporin hypersensitivity. What does this tell us about the beta-lactam epitopes for the IgE?
The epitope is not the beta-lactam but likely a side chain.
List the 1st generation cephalosporins (3).
- Cephalexin
- Cefadroxil
- Cephapirin
How is cephalexin administered?
Orally
How is cefadroxil administered?
Orally
How is cephapirin administered?
Intramammary
List the 3rd generation cephalosporins (3).
- Cefpodoxime
- Ceftiofur
- Cefovecin
How is cefpodoxime administered?
Orally
How is ceftiofur administered?
Parenterally, intrammaray
How is cefovecin administered?
Parenterally
How is cefepime used in humans?
IV to treat Pseudomonas
Which drug has cross-reactivity with cefepime?
Cefquinome
List the 4th generation cephalosporins (2).
- Cefepime
2. Cefquinome
What is the 5th generation cephalosporin?
Ceftobiprole
What is the spectrum of 1st generation cephalosporins (cephalexin, cefadroxil, cephapirin)?
Gram (+)
What is the spectrum of 3rd generation cephalosporins (cefpodoxime, ceftiofur, cefovecin)?
Gram (+)
What is the spectrum of 4th generation cephalosporins (cefepime, cefquinome)?
Gram (-)
Which generation of cephalosporins is best at crossing the blood-brain-barrier?
3rd generation cephalosporins
True or False: Cephalosporins are well-absorbed orally.
True
The pKa of cephalosporins is 4-5, so they are ____ in the stomach.
Non-ionized
Cephalosporins are more OR less ionized in the plasma compared to penicillins?
LESS
Because cephalosporins are less ionized in the plasma than penicillins, do they have a higher or lower Vd?
Higher Vd
Are cephalosporins concentration-dependent, time-dependent, or AUC-dependent?
Time-dependent
Sustained-release formulations are available fro which cephalosporins?
- Cefovecin
2. Ceftiofur
There is also a ready-to-use formulation of ceftiofur. How does this formulation differ from the sustained-release?
The RTU formulation is NOT extended release and should NOT be administered IV.
There are no potentiators available for cephalosporins, except one exception. What is that exception?
Cefpodoxime + clavulanic acid
What is the #1 drug choice for staphylococcal pyoderma in the dog?
Cephalexin (1st generation cephalosporin)
What is Cefpodoxime used for in small animals?
Cephalexin-insensitive pyoderma
What is Cefovecin used for in the cat?
Treatment of pyoderma
What is the disadvantage to Cefovecin in the dog?
Cost - too expensive
Put the following in order of increasing cost: cephalexin, cefovecin, cefpodoxime.
Cephalexin –> cefpodoxime –> cefovecin
What is the common name for Cefpodoxime?
Simplicef
For what is Cephapirin used in the large animal?
Mastitis in dairy cattle, lactating (Today) or dry (Tomorrow)
For what is Ceftiofur used in the horse?
Streptococcal pneumonia
For what is Ceftiofur used in the pig?
Respiratory disease, including Salmonella cholerasuis
For what is Ceftiofur used in dairy cattle?
Lactating or dry mastitis
Which drug is the drug of choice for coliform mastitis?
Ceftiofur spectramast
For what is Ceftiofur used in beef cattle?
- Pneumonia
2. Foot rot
What are the 2 Carbapenems discussed?
- Imipenem
2. Meropenem
Imipenem is metabolized by renal dehydropeptidase. What inhibits this enzyme and is thus included with imipenem?
Cilastin
Are Carbapenems concentration-dependent, time-dependent, or AUC-dependent?
Time-dependent
How would you administer Carbapenems and why?
Carbapenems are very ionic and irritation so only give IM in conjunction with lidocaine or IV.
What is the drug class with the WIDEST spectrum of any antimicrobial group?
Carbapenems
Carbapenems are mostly used for what type of infections?
Septic gram (-) infections
List the potentiators for the Monobactams.
There are none
What is the spectrum of the Monobactams?
Gram (-) aerobes
What is the spectrum of Bacitracin?
Gram (+) aerobes
How would you administer Bacitracin?
Topically, enterically, or orally (DO NOT INJECT AS THIS IS A NEPHROTOXIN)
For what is Bacitracin used in the pig?
Swine dysentery (Brachyspira)
For what is Bacitracin used in poultry?
Coccidiosis